2014年

作者：来源：时间：2015-07-01 字体<　大　中　小　>

Intrinsic optical torque of cylindrical vector beams on Rayleigh absorptive spherical particles

Li, Manman1, 2; Yan, Shaohui1; Yao, Baoli1; Lei, Ming1; Yang, Yanlong1; Min, Junwei1; Dan, Dan1 Source: Journal of the Optical Society of America A: Optics and Image Science, and Vision, v 31, n 8, p 1710-1715, August 1, 2014

; ISSN: 10847529, E-ISSN: 15208532; DOI: 10.1364/JOSAA.31.001710Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: The intrinsic optical torque of a focused cylindrical vector beam on a Rayleigh absorptive spherical particle is calculated via the corrected dipole approximation. Numerical results show that, for the radially polarized input field, the torque is distributed in the focal plane strictly along the azimuthal direction anywhere except at the focus. This shows a completely different property from what is observed in the focusing of a circularly polarized beam, where a strong axial torque component arises. For other cylindrically polarized input fields, the torque tends to align itself along the radial direction, as the polarization angle (the angle between the electric vector and the radial direction) changes from 0° to 90°. When limited to considering the torque at the equilibrium position, we find that only for those input fields with polarization angles larger than 50°, the particle experiences a nonzero torque at its equilibrium position. This is verified by showing quantitatively the effects of the polarization angle on the magnitude and orientation of the torque at the equilibrium position. © 2014 Optical Society of America. (28 refs.)Main Heading: TorqueControlled terms: PolarizationUncontrolled terms: Azimuthal direction - Circularly polarized beam - Cylindrical vector beam - Cylindrically polarized - Dipole approximation - Equilibrium positions - Polarization angle - Radially polarizedClassification Code: 421 Strength of Building Materials; Mechanical Properties - 711.1 Electromagnetic Waves in Different Media

Database: Compendex

Performance of diode-pumped continuous wave tunable and passively Q-switched Nd,Mg:LiTaO<inf>3</inf> laser

Feng, T.1; Li, T.1; Zhao, S.1; Li, Q.2; Yang, K.1; Zhao, J.1; Qiao, W.1; Hang, Y.3; Zhang, P.3; Wang, Y.4; Xu, J.2 Source: Optics Communications, v 325, p 92-94, August 30, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.03.088;

Publisher: ElsevierAuthor affiliation: 1 School of Information Science and Engineering, Shandong University, Jinan, Shandong 250100, China2 Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China3 Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800, China4 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The lasing characteristics of Nd,Mg:LiTaO<inf>3</inf> crystal is demonstrated in this paper. The continuous wave laser spectra can be tuned from 1079.8 nm to 1083.1 nm and 1089.6 nm to 1093.2 nm. By employing a single-walled carbon nanotube (SWCNT) as saturable absorber (SA), the shortest pulse duration of 380 ns under repetition rate of 103 kHz is obtained, corresponding to a single pulse energy of 3.2 μJ. © 2014 Elsevier B.V. (21 refs.)Main Heading: Q switchingControlled terms: Continuous wave lasers - Q switched lasers - Saturable absorbers - Single-walled carbon nanotubes (SWCN) - Solid state lasersUncontrolled terms: Continuous Wave - Lasing characteristics - Non-linear optical material - Passively Q-switched - Pulse durations - Repetition rate - Single pulse energy - Singlewalled carbon nanotube (SWCNT)Classification Code: 744 Lasers - 761 Nanotechnology

Database: Compendex

Coded aperture spectral data restoration based on two-step iterative shrinkage/threshold

Li, Yun1, 2; Hu, Bing-Liang1; Wang, Shuang1; Li, Ran1; Shi, Da-Lian1, 2 Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, v 34, n 3, p 847-850, March 2014; Language: Chinese

; ISSN: 10000593; DOI: 10.3964/j.issn.1000-0593(2014)03-0847-04;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710068, China2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Coded aperture imaging spectrometer based on the concept of compressed sensing can acquire the spectral diagram of object. Coded aperture spectral data restoration reconstructs three-dimensional data cube from two-dimensional coded image. The two-step iterative shrinkage/thresholding algorithms were derived from the iterative shrinkage threshold algorithm and weighted iterative shrinkage algorithm. Recovering coded aperture spectral data using the two-step iterative shrinkage/thresholding algorithms obtained the three-dimensional spectral data cube successfully. (13 refs.)Main Heading: Iterative methodsControlled terms: Algorithms - Compressed sensing - Restoration - Shrinkage - Signal reconstruction - Three dimensionalUncontrolled terms: Coded aperture imaging - Coded apertures - Iterative Shrinkage algorithms - Iterative shrinkages - Spectral data - Three-dimensional data - Threshold algorithms - Two-step iterative shrinkagesClassification Code: 402 Buildings and Towers - 409 Civil Engineering, General - 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 921 Mathematics - 921.6 Numerical Methods - 951 Materials Science

Database: Compendex

Experimental studies of multiple pulses in a passively ytterbium-doped fiber laser based on graphene-oxide saturable absorber

Huang, Shi-Sheng1; Wang, Yong-Gang2; Li, Hui-Quan1; Lin, Rong-Yong1; Yan, Pei-Guang1 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 8, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.084202; Article number: 084202;

Publisher: Science PressAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The different multiple pulse phenomena are experimentally studied in a passively mode-locked ytterbium-doped fiber laser based on graphene-oxide saturable absorber (GOSA) with net normal dispersion cavity. At the same pump power with different polarization orientations, we observe the multiple pulse phenomena, including harmonic mode-locking of rectangular pulses, dissipative solitons, quasi-harmonic mode-locking, periodical peak modulation, multipulse bunches, multipulse cluster, and chaotic multipulse. The inserted 2 nm narrow bandwidth filter is important for limiting the gain bandwidth and shaping pulses. Adjusting the polarization controller is equivalent to changing the gain in the laser cavity, which is the main reason for the formation of different multiple pulses states. This is the first time that different multiple pulses states have been observed in an-normal-dispersion Yb-doped fiber laser with graphene-oxide saturable absorber. These results could extend the understanding of multiple pulse dynamics in GOSA mode-locked fiber lasers. © 2014 Chinese Physical Society. (27 refs.)Main Heading: Optical pumpingControlled terms: Fiber lasers - Graphene - Locks (fasteners) - Passive mode locking - Polarization - Pulse shaping - Saturable absorbers - Solitons - YtterbiumUncontrolled terms: All normal dispersions - Graphene-oxide - Multiple pulse - Passively mode-locked - Polarization controllers - Polarization orientation - Yb-doped fiber lasers - Ytterbium-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 713.4 Pulse Circuits - 741.1 Light/Optics - 741.1.2 Fiber Optics - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 931.3 Atomic and Molecular Physics

Database: Compendex

Contrast enhancement-based forensics in digital images

Cao, Gang1, 2; Zhao, Yao1, 3; Ni, Rongrong1, 4; Li, Xuelong5 Source: IEEE Transactions on Information Forensics and Security, v 9, n 3, p 515-525, March 2014

; ISSN: 15566013; DOI: 10.1109/TIFS.2014.2300937; Article number: 6714577;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Institute of Information Science, Beijing Jiaotong University, Beijing 100044, China2 School of Computer Science, Communication University of China, Beijing 100024, China3 State Key Laboratory of Rail Traffic Control and Safety, Beijing 100044, China4 Beijing Key Laboratory of Advanced Information Science and Network Technology, Beijing 100044, China5 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: As a retouching manipulation, contrast enhancement is typically used to adjust the global brightness and contrast of digital images. Malicious users may also perform contrast enhancement locally for creating a realistic composite image. As such it is significant to detect contrast enhancement blindly for verifying the originality and authenticity of the digital images. In this paper, we propose two novel algorithms to detect the contrast enhancement involved manipulations in digital images. First, we focus on the detection of global contrast enhancement applied to the previously JPEG-compressed images, which are widespread in real applications. The histogram peak/gap artifacts incurred by the JPEG compression and pixel value mappings are analyzed theoretically, and distinguished by identifying the zero-height gap fingerprints. Second, we propose to identify the composite image created by enforcing contrast adjustment on either one or both source regions. The positions of detected blockwise peak/gap bins are clustered for recognizing the contrast enhancement mappings applied to different source regions. The consistency between regional artifacts is checked for discovering the image forgeries and locating the composition boundary. Extensive experiments have verified the effectiveness and efficacy of the proposed techniques. © 2005-2012 IEEE. (26 refs.)Main Heading: Image processingControlled terms: Algorithms - Computer visionUncontrolled terms: Composite images - Contrast adjustment - Contrast Enhancement - Digital forensic - Global contrasts - Image forgery - JPEG compression - Real applicationsClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 741.2 Vision - 921 Mathematics

Database: Compendex

From heuristic optimization to dictionary learning: A review and comprehensive comparison of image denoising algorithms

Shao, Ling1; Yan, Ruomei2; Li, Xuelong3; Liu, Yan4 Source: IEEE Transactions on Cybernetics, v 44, n 7, p 1001-1013, July 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2278548; Article number: 6587769;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China4 Department of Computing, University of Hong Kong Polytechnic, Hung Hom, Kowloon, Hong Kong

Abstract: Image denoising is a well explored topic in the field of image processing. In the past several decades, the progress made in image denoising has benefited from the improved modeling of natural images. In this paper, we introduce a new taxonomy based on image representations for a better understanding of state-of-the-art image denoising techniques. Within each category, several representative algorithms are selected for evaluation and comparison. The experimental results are discussed and analyzed to determine the overall advantages and disadvantages of each category. In general, the nonlocal methods within each category produce better denoising results than local ones. In addition, methods based on overcomplete representations using learned dictionaries perform better than others. The comprehensive study in this paper would serve as a good reference and stimulate new research ideas in image denoising. © 2013 IEEE. (77 refs.)Main Heading: Image denoisingControlled terms: Adaptive filtering - Algorithms - Image processing - SurveyingUncontrolled terms: Dictionary learning - evaluation - Sparse coding - Spatial domains - Transform domainClassification Code: 405.3 Surveying - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 731.1 Control Systems - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Hybrid adaptive robust controller on inertial Gyro LOS platform

Luo, Cui Hua1, 2, 3; Ma, Cai Wen2; Li, Yan2 Source: Applied Mechanics and Materials, v 513-517, p 2910-2913, 2014, Applied Science, Materials Science and Information Technologies in Industry

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350125; DOI: 10.4028/www.scientific.net/AMM.513-517.2910; Conference: 2014 International Conference on Advances in Materials Science and Information Technologies in Industry, AMSITI 2014, January 11, 2014 - January 12, 2014; Sponsor: Engineering Village; INTIEA; ISI Proceedings; Scientific.Net; Trans Tech Publications inc.;

Publisher: Trans Tech PublicationsAuthor affiliation: 1 Dept. Electrical and Information Engineering, Southwest University for Nationalities, Chengdu, 610041, China2 Dept. Opt-electronicTracking and Measurement Technology, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, 710119, China3 University of Chinese Academy of Sciences, Beijing, 100038, China

Abstract: This paper was presented one new modified controller scheme for inertial gyro control system. Based on Narendra's hybrid adaptive law, the modified algorithm was variable metric that took use of parameter matrix Γ<inf>k</inf> to obtain two updating laws in turn online. The key modified contents were: 1) the output y(t)was passed by one low-pass filter, 2) the parameter was updating in term of one proper initial Γ0 and the measurable values. The objective of the proposed new adaptive robust control schemes was to achieve fast convergence of parameter updating, and promise good robust stability of control system during tracking, reduce the tracking error at start-time with filtered output. © (2014) Trans Tech Publications, Switzerland. (7 refs.)Main Heading: Information technologyControlled terms: Control systems - Gyroscopes - Materials science - Robust control - Robustness (control systems)Uncontrolled terms: Adaptive Control - Adaptive robust control - Adaptive robust controllers - Asymptotical stability - Fast convergence - Modified algorithms - Parameter matrices - Robust stabilityClassification Code: 731 Automatic Control Principles and Applications - 731.1 Control Systems - 903 Information Science - 943.1 Mechanical Instruments - 951 Materials Science

Database: Compendex

GaAs film for photon-enhanced thermionic emission solar harvesters

Tang, Weidong1, 2; Yang, Wenzheng3; Yang, Yang1, 2; Sun, Chuandong3; Cai, Zhipeng1, 2 Source: Materials Science in Semiconductor Processing, v 25, p 143-147, September 2014

; ISSN: 13698001; DOI: 10.1016/j.mssp.2013.10.009;

Publisher: Elsevier LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China3 Key Laboratory of Ultrafast Photoelectric Diagnostics Technology, Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China

Abstract: A novel concept for solar electricity generation named photon-enhanced thermionic emission (PETE) was recently proposed for harvesting solar photonic and thermionic energies simultaneously. Comparative investigations showed that the conversion efficiency of PETE can theoretically exceed 40%. In this paper, an electric field-assisted PETE experiment was carried out to demonstrate the possibility of using GaAs epitaxial films in PETE solar devices. The solar photonic and thermionic effects were simulated by a red light-emitting diode array and a heat resistor, respectively. Surface electron affinity was decreased by an electric field instead of Cs/Cs-O coating. The experimental results agreed with calculated values, and a distinct enhancement was observed in the thermionic emission produced by photoexcitation compared with thermionic field emission produced by an illuminated sample and the sample emission obtained in the dark. © 2013 Elsevier Ltd. (15 refs.)Main Heading: Thermionic emissionControlled terms: Electric fields - Field emission - Gallium arsenide - Light emitting diodes - Photons - Semiconducting galliumUncontrolled terms: Calculated values - GaAs films - PETE - Sample emission - Solar electricity - Thermionic effects - Thermionic energies - Thermionic field emissionClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 712.1.1 Single Element Semiconducting Materials - 712.2 Thermionic Materials - 741.1 Light/Optics - 804 Chemical Products Generally - 932 High Energy Physics; Nuclear Physics; Plasma Physics

Database: Compendex

A full aperture backscattering light diagnostic system installed on the Shenguang-III prototype laser facility

Xu, Tao1; Mei, Yu1; Wei, Huiyue1; Peng, Xiaoshi1; Wang, Feng1; Yang, Dong1; Liu, Shenye1; Yan, Yadong2 Source: Plasma Science and Technology, v 16, n 6, p 567-570, June 2014

; ISSN: 10090630; DOI: 10.1088/1009-0630/16/6/05;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China2 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 721000, China

Abstract: A full aperture backscattering light diagnostic system (FABLDS) implemented on the Shen Guang-III Prototype Laser Facility is described in the paper. FABLDS measures both stimulated brillouin scattering (SBS) and stimulated Raman scattering (SRS) with a series of optical detectors. Energy sensors record the integrated energy, and streak cameras coupled with spectrometers measure the temporal spectrum of the backscattering light. This paper provides an overview of the FABLDS and detailed descriptions of the optical path. Special components, including off-axis parabolic mirror, spatial filter and optical light filters, are incorporated along the beam path for purifying the scattering light. Several hohlraum targets were employed, including C<inf>5</inf>H<inf>12</inf> gas-filled targets and empty targets in the experiments. Results presented in the paper indicate that the fraction of backscatter light has been obviously shrinked when the laser is smoothed by continuous phase plates (CPP). (15 refs.)Main Heading: LightControlled terms: Backscattering - Detectors - Mirrors - Stimulated Brillouin scatteringUncontrolled terms: Backscattering light - CPP - Hohlraum targets - ICF - Off-axis parabolic mirrorsClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 914 Safety Engineering

Database: Compendex

Study on spatial measurement accuracy of standard laser sourcenear-field parameters

Duan, Yaxuan1, 2; Chen, Yongquan1; Li, Kun1; Zhao, Jianke1; Long, Jiangbo1; Gao, Limin1 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 3, March 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.0308003; Article number: 0308003;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi, 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: In order to study on the spatial measurement accuracy of standard laser source near-field parameters, the theoretical model of near-field intensity distribution of standard laser source is established. The surface response non-uniformity correction program of the scientific grade CCD and calculation algorithm of laser near field is proposed. Using corrected scientific grade CCD and two-dimensional scanning device, the 50 mm × 50 mm soft-stop images of 1053 nm standard laser source are obtained by S-shaped scanning and capturing. The near-field image of standard laser source is got by the sub-aperture image mosaic. The test results of near-field intensity distribution are accordance with the theoretical results. The main difference between them is the high frequency components mainly caused by the roughness of off-axis parabolic mirror and random noise of the scientific grade CCD. The analysis of near-field parameters test results is that the uncertainty of modulation is 0.08 (k=2), and the uncertainty of contrast is 0.01 (k=2). The near-field measurement confidence of laser measurement system of National Science and Engineering is improved by the study results. (15 refs.)Main Heading: Parameter estimationControlled terms: Lasers - Measurements - Modulation - Uncertainty analysisUncontrolled terms: Contrast - High frequency components - Laser measurement systems - Near-field - Nonuniformity correction - Off-axis parabolic mirrors - Two-dimensional scanning - UncertaintyClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 731.1 Control Systems - 744.1 Lasers, General - 922.1 Probability Theory - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Irregular image adaptive focusing system for diffraction grating

Wang, Wei1; Li, Dong-Jian1; Li, Hong-Guang1; Wang, Zheng-Zhou1; Cao, Shi-Kang1 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 4, p 822-828, April 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142204.0822;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The characteristics of faculae for a larger diameter diffraction grating were analyzed, and different problems and their processing methods in self-adaptive auto-focusing of irregular images for the diffraction grating were discussed. A group of methods to control the auto-focusing of the irregular facula of the diffraction grating were proposed and a self-adaptive auto-focusing device were developed to achieve the offline detection of sampling distance and sampling angle for the diffraction grating. By optimizing threshold theory, the image was divided into two parts, facula area and background. On the basis of the mathematical morphology theory, the facula area, major and minor axis lengths and image center were calculated. Then, the adaptive focusing methods were implemented by analyzing the corresponding relationship between image center position and leveling motor, the lengths of major and minor axes and the axial motor. Finally, focusing iteration and centroid search were performed by combining the area minimization with the golden section algorithm. Test results show that the standard deviation of sampling distance is 412.5 μm and that of sampling angle is 10.35″, which meets the requirements for sampling distance and sampling angle less than 1000 μm and 30″, respectively. This device is characterized by simple structure, high reliability, strong anti-interference ability, and has been applied in a large aperture diffraction grating comprehensive diagnosis platform. (15 refs.)Main Heading: Diffraction gratingsControlled terms: Diffraction - Focusing - Image segmentation - Iterative methods - Mathematical morphology - Phase structureUncontrolled terms: Adaptive focusing - Golden section algorithm - Irregular image - Mathematical morphology theories - Minor axis lengths - Optimal threshold - Simple structures - Standard deviationClassification Code: 741.1 Light/Optics - 741.3 Optical Devices and Systems - 921 Mathematics - 921.6 Numerical Methods - 933 Solid State Physics

Database: Compendex

Double optical path automatic positioning system of Shenguang III facility diagnostic instrument platform

Wang, Wei1; He, Junhua1; Zhang, Min1; Wei, Mingzhi1; Yan, Yadong1; Wang, Wei1; Wang, Zhengzhou1; Yang, Zhenghua2; Yang, Pin2 Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams, v 26, n 7, July 2014; Language: Chinese

; ISSN: 10014322; DOI: 10.11884/HPLPB201426.072003; Article number: 072003;

Publisher: Editorial Office of High Power Laser and Particle BeamsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Research Center of Laser Fusion, CAEP, P.O. Box 919-988, Mianyang 621900, China

Abstract: The platform which is used to carry diagnostic instruments on Shenguang facility requires high positioning accuracy and working stability, and can aim at the target with reliability. A double optical path automatic adjusting and aiming system is designed, its position accuracy is 20 μm. It employs a double optical image system and a 3-DOF motion component. In this system, visual servo technology is used to realize the automatic aiming. Automatic positioning test indicates that pointing accuracy is 11 μm in x direction, 12 μm in y direction and radical positioning accuracy is 14 μm. Laser shot test with X-ray framing camera shows that the automatic aiming system can satisfy the projects requirement. (13 refs.)Main Heading: Visual servoingControlled terms: Geometrical opticsUncontrolled terms: 3-DOF motions - Automatic aiming - Automatic positioning systems - Double optical paths - Instrument platforms - Positioning accuracy - Working stabilities - X-ray framing cameraClassification Code: 731 Automatic Control Principles and Applications - 732 Control Devices - 741.1 Light/Optics

Database: Compendex

Joint embedding learning and sparse regression: A framework for unsupervised feature selection

Hou, Chenping1; Nie, Feiping2; Li, Xuelong3; Yi, Dongyun1; Wu, Yi1 Source: IEEE Transactions on Cybernetics, v 44, n 6, p 793-804, June 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2272642; Article number: 6565365;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Department of Mathematics and Systems Science, National University of Defense Technology, Changsha, Hunan 410073, China2 Department of Computer Science and Engineering, University of Texas, Arlington, TX 76019, United States3 State Key Laboratory of Transient Optics and Photonics, Center for Optical Imagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, Shaanxi, China

Abstract: Feature selection has aroused considerable research interests during the last few decades. Traditional learning-based feature selection methods separate embedding learning and feature ranking. In this paper, we propose a novel unsupervised feature selection framework, termed as the joint embedding learning and sparse regression (JELSR), in which the embedding learning and sparse regression are jointly performed. Specifically, the proposed JELSR joins embedding learning with sparse regression to perform feature selection. To show the effectiveness of the proposed framework, we also provide a method using the weight via local linear approximation and adding the &ell;<inf>2,1</inf>-norm regularization, and design an effective algorithm to solve the corresponding optimization problem. Furthermore, we also conduct some insightful discussion on the proposed feature selection approach, including the convergence analysis, computational complexity, and parameter determination. In all, the proposed framework not only provides a new perspective to view traditional methods but also evokes some other deep researches for feature selection. Compared with traditional unsupervised feature selection methods, our approach could integrate the merits of embedding learning and sparse regression. Promising experimental results on different kinds of data sets, including image, voice data and biological data, have validated the effectiveness of our proposed algorithm. © 2013 IEEE. (45 refs.)Main Heading: Regression analysisControlled terms: Approximation algorithms - Bioinformatics - Feature extraction - Optimization - Pattern recognitionUncontrolled terms: Effective algorithms - Embedding learning - Feature selection methods - Local linear approximation - Optimization problems - Parameter determination - Sparse regression - Unsupervised feature selectionClassification Code: 716 Telecommunication; Radar, Radio and Television - 903 Information Science - 921 Mathematics - 921.5 Optimization Techniques - 922.2 Mathematical Statistics

Database: Compendex

Two different output states from an all-normal dispersion yetterbium-doped fiber laser using graphene-oxide as a saturable absorber

Huang, S.S.1; Wang, Y.G.2; Yan, P.G.1; Zhang, G.L.1; Zhao, J.Q.1; Li, H.Q.1; Lin, R.Y.1 Source: Laser Physics, v 24, n 6, June 2014

; ISSN: 1054660X, E-ISSN: 15556611; DOI: 10.1088/1054-660X/24/6/065108; Article number: 065108;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, College of Electronic Science and Technology, Shenzhen University, Shenzhen, GUANGDONG 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We have experimentally obtained two different applied output states from an all-normal dispersion yetterbium-doped fiber laser using graphene-oxide as a saturable absorber without additional components (like tunable filter, dispersion compensation), including the wavelength-switched mode-locking operation, and the dissipative soliton resonance (DSR) operation with high energy square pulses. These two experimental phenomena indicate that the graphene-oxide saturable absorber can be successfully used to realize different mode-locking states in a fiber laser by system-parameter management. The yetterbium-doped fiber laser in all-normal dispersion with flexible outputs can meet different application needs. © 2014 Astro Ltd. (25 refs.)Main Heading: Dispersion (waves)Controlled terms: Dispersions - Fiber lasers - Graphene - Locks (fasteners) - Saturable absorbers - SolitonsUncontrolled terms: Dissipative solitons - graphene-oxide - Passive mode-locking - Wavelength-switched - Yb-doped fiber lasersClassification Code: 601.3 Mechanisms - 711.1 Electromagnetic Waves in Different Media - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 931.3 Atomic and Molecular Physics - 951 Materials Science

Database: Compendex

Mode locked fiber laser based on single-walled carbon nanotube in heavy water

Yu, Zhenhua1; Wang, Yonggang2; Tian, Jinrong1; Dou, Zhiyuan1; Li, Kexuan1; Song, Yanrong1 Source: IEEE Photonics Technology Letters, v 26, n 18, p 1829-1831, September 15, 2014

; ISSN: 10411135; DOI: 10.1109/LPT.2014.2336873; Article number: 6851927;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Institute of Information Photonics Technology, College of Applied Sciences, Beijing University of Technology, Beijing, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Carbon nanotubes in heavy water (deuteroxide, D<inf>2</inf>O) dispersion was fabricated and used as a saturable absorber for mode locking in a fiber laser. Such liquid absorber has the virtues of good optical transparency, high heat dissipation, and high damage threshold. A passively mode locked fiber laser with it was demonstrated. The pulsewidth is 306 fs with the maximum average output power of 20 mW. The center of the wavelength is 1560 nm with 15.2-nm spectral width. © 1989-2012 IEEE. (20 refs.)Main Heading: Fiber lasersControlled terms: Erbium - Heavy water - Locks (fasteners) - Passive mode locking - Saturable absorbers - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Average output power - Damage threshold - Mode-locked laser - Optical transparency - Passively mode-locked fiber lasers - Pulsewidths - Spectral widthsClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Statistical quantization for similarity search

Wang, Qi1; Zhu, Guokang2; Yuan, Yuan2 Source: Computer Vision and Image Understanding, v 124, p 22-30, July 2014

; ISSN: 10773142, E-ISSN: 1090235X; DOI: 10.1016/j.cviu.2014.03.002;

Publisher: Academic Press Inc.Author affiliation: 1 Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Approximate nearest neighbor search has attracted much attention recently, which allows for fast query with a predictable sacrifice in search quality. Among the related works, k-means quantizers are possibly the most adaptive methods, and have shown the superiority on search accuracy than the others. However, a common problem shared by the traditional quantizers is that during the out-of-sample extension process, the naive strategy considers only the similarities in Euclidean space without taking into account the statistical and geometrical properties of the data. To cope with this problem, in this paper a novel approach is proposed by formulating a generalized likelihood ratio analysis. In particular, the proposed method takes a physically meaningful discrimination on the affiliations of the new samples with respect to the obtained Voronoi cells. This discrimination essentially imposes the measure of statistical consistency on out-of-sample extension. The experimental studies on two large data sets show that the proposed method is more effective than the benchmark algorithms. © 2014 Elsevier Inc. All rights reserved. (42 refs.)Main Heading: Image retrievalControlled terms: Artificial intelligence - Binary codes - Computer vision - Geometry - Learning systemsUncontrolled terms: Approximate Nearest Neighbor Search - Generalized likelihood ratio - Geometrical property - Hashing - Out-of-sample extension - Quantization - Similarity search - Statistical consistenciesClassification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 741.2 Vision - 921 Mathematics

Database: Compendex

CMOS compatible nonlinear optics based on Hydex

Caspani, Lucia1; Pasquazi, Alessia1, 2; Peccianti, Marco1, 2; Reimer, Christian1; Clerici, Matteo1, 3; Ferrera, Marcello1, 3; Razzari, Luca1; Duchesne, David1; Little, Brent E.4; Chu, Sai T.5; Moss, David J.1, 6; Morandotti, R.1 Source: 2014 OptoElectronics and Communication Conference, OECC 2014 and Australian Conference on Optical Fibre Technology, ACOFT 2014, p 398-400, 2014, 2014 OptoElectronics and Communication Conference, OECC 2014 and Australian Conference on Optical Fibre Technology, ACOFT 2014; ISBN-13: 9781922107213; Article number: 6888122; Conference: 19th OptoElectronics and Communications Conference, OECC 2014 and the 39th Australian Conference on Optical Fibre Technology, ACOFT 2014, July 6, 2014 - July 10, 2014; Sponsor: The University of Melbourne;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes, QC J3X 1S2, Canada2 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, United Kingdom3 School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom4 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, China5 City University of Hong Kong, Department of Physics and Material Science, Tat Chee Avenue, Hong Kong, Hong Kong6 School of Electrical and Computer Engineering, RMIT University, Melbourne, VIC 3001, Australia

Abstract: We review our work on ultrafast laser sources and frequency generation in high-index doped silica (Hydex®) integrated structures. © 2014 Engineers Australia. (13 refs.)Main Heading: Optoelectronic devicesControlled terms: Nonlinear optics - Optical communication - Optical fibers - Ultrafast lasersUncontrolled terms: CMOS Compatible - Doped silicas - Frequency generation - High-index - Integrated structureClassification Code: 717.1 Optical Communication Systems - 717.2 Optical Communication Equipment - 741 Light, Optics and Optical Devices - 744.1 Lasers, General

Database: Compendex

Conversion efficiency of photon enhanced thermionic emission solar converters with exponential doping GaAs cathodes

Tang, Wei-Dong1, 2; Yang, Wen-Zheng1; Yang, Yang1, 2; Sun, Chuan-Dong1; Cai, Zhi-Peng1, 2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 6, June 2014

; ISSN: 10044213; DOI: 10.3788/gzxb20144306.0625002; Article number: 0625002;

Abstract: Photon-enhanced thermionic emission solar energy converter is a new highly efficient solar energy utilization technologies. An exponential doping GaAs material was presented as the cathode of photon-enhanced thermionic emission solar converter. The conversion efficiencies of the photon-enhanced thermionic emission solar devices with exponential doping GaAs were theoretically analyzed by using the energy-balance and diffusion-drift-emission models. The results show that exponential doping GaAs prominently enhances photon-enhanced thermionic emission conversion, and the efficiency of photon-enhanced thermionic emission solar converters with exponential doping GaAs cathodes is a monotonically increasing function of sun concentration and a monotonically decreasing function of cathode surface recombination velocities. The efficiency of the converter can reach 30% at a flux concentration larger than 200 suns and surface recombination velocities maintained at fewer than 104 cm/s. (20 refs.)Main Heading: CathodesControlled terms: Conversion efficiency - Energy utilization - Gallium arsenide - Photons - Semiconducting gallium - Solar energy - Thermionic emissionUncontrolled terms: Decreasing functions - Energy converters - Flux concentration - GaAs - Increasing functions - PETE - Solar converters - Surface recombination velocitiesClassification Code: 525.3 Energy Utilization - 525.5 Energy Conversion Issues - 615.2 Solar Power - 704.1 Electric Components - 712.1.1 Single Element Semiconducting Materials - 712.2 Thermionic Materials - 741.1 Light/Optics - 804 Chemical Products Generally

Database: Compendex

Expanded-core waveguides written by femtosecond laser irradiation in bulk optical glasses

Liu, Xin1, 2; Zhang, Wenfu1; Zhao, Wei1; Stoian, Razvan3; Cheng, Guanghua1 Source: Optics Express, v 22, n 23, p 28771-28782, November 17, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.028771;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 Laboratoire Hubert Curien, Université de Lyon, Université Jean Monnet, Saint Etienne, France

Abstract: Expanded-core structures based on layered increased index (type I) waveguiding traces are fabricated by ultrafast laser photoinscription in bulk optical glasses, with examples for fused silica and chalcogenide glasses. The expanded-core waveguides can serve for large-mode-area guiding concepts and their feasibility is experimentally investigated. A parametric study of the geometry, number of traces and index contrast indicates the possibility to design guided modes characteristics as exemplified in fused silica. A specific arrangement consisting of 8 traces of guiding layers with 6μm separation exhibit single-mode transport properties with mode field area of &sim;805μm2. The condition of single mode operation is also discussed in the frame of the dispersion relation of light guiding in periodical dielectric structures. The supported supermode of expanded-core structures can be controlled by careful design of the refractive index change, the number of guiding layers and the thickness of the interlayers. Inspection of the propagation characteristics shows equally low loss features. A Y-branching splitter based on expanded-core concept conserving single mode characteristics is fabricated. The optical design is equally successfully tested in chalcogenide Gallium Lanthanum Sulfide glass. Ultrafast laser inscribed expanded-core waveguiding provides therefore an interesting path of fabricating large mode area waveguides usable in near infrared and mid-infrared region beneficial for applications requiring high power or large mode dimensions. (31 refs.)Main Heading: Fused silicaControlled terms: Chalcogenides - Dispersions - Glass - Infrared devices - Optical design - Optical glass - Refractive index - Ultrafast lasers - WaveguidesUncontrolled terms: Dielectric structure - Dispersion relations - Expanded-core waveguides - Gallium lanthanum sulfides - Mid-infrared regions - Propagation characteristics - Refractive index changes - Single mode operationClassification Code: 714.3 Waveguides - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 812.3 Glass - 951 Materials Science

Database: Compendex

Facial skin beautification using adaptive region-aware masks

Liang, Lingyu1; Jin, Lianwen1; Li, Xuelong2 Source: IEEE Transactions on Cybernetics, v 44, n 12, p 2600-2612, December 1, 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2014.2311033; Article number: 2311033;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou, China2 Center for Optical Imagery Analysis and Learning (OPTIMAL), Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: In this paper, we propose a unified facial beautification framework with respect to skin homogeneity, lighting, and color. A novel region-aware mask is constructed for skin manipulation, which can automatically select the edited regions with great precision. Inspired by the state-of-the-art edit propagation techniques, we present an adaptive edge-preserving energy minimization model with a spatially variant parameter and a high-dimensional guided feature space for mask generation. Using region-aware masks, our method facilitates more flexible and accurate facial skin enhancement while the complex manipulations are simplified considerably. In our beautification framework, a portrait is decomposed into smoothness, lighting, and color layers by an edge-preserving operator. Next, facial landmarks and significant features are extracted as input constraints for mask generation. After three region-aware masks have been obtained, a user can perform facial beautification simply by adjusting the skin parameters. Furthermore, the combinations of parameters can be optimized automatically, depending on the data priors and psychological knowledge. We performed both qualitative and quantitative evaluation for our method using faces with different genders, races, ages, poses, and backgrounds from various databases. The experimental results demonstrate that our technique is superior to previous methods and comparable to commercial systems, for example, PicTreat, Portrait+, and Portraiture. (63 refs.)Main Heading: LightingUncontrolled terms: Edge-preserving smoothing - Edit propagation - Face beautification - Facial attractiveness - Image editingClassification Code: 707 Illuminating Engineering

Database: Compendex

Design of magnetic focusing femtosecond streak tube with prepositive traveling wave deflector

Wang, Qiangqiang1, 3; Tian, Jinshou1; Ding, Yongkun2; Wen, Wenlong1; Liu, Rong1, 3; Lu, Yu1; Xu, Xiangyan1; Cao, Xibin1; Wang, Xing1; Wang, Junfeng1 Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams, v 26, n 3, March 2014; Language: Chinese

; ISSN: 10014322; DOI: 10.3788/HPLPB201426.034005; Article number: 034005;

Publisher: Editorial Office of High Power Laser and Particle BeamsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Research Center of Laser Fusion, CAEP, P. O. Box 919-988, Mianyang 621900, China3 Graduate University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: A 265 mm long magnetic focusing femtosecond streak tube with a prepositive traveling wave deflector was theoretically designed. The initial parameters of the electrons emitted both from an ideal point and a slit on the surface of the photoelectric cathode were sampled with Monte Carlo method. The trajectory of the electrons were followed in the CST particle studio, after which the distribution of the electrons on the best image plane and the transit time of the electrons were statistically analyzed. To evaluate the characteristics of the streak tube, this paper also calculated the modulation transform function. The results show that the diameter of the effective area on the photoelectric cathode reaches up to 6 mm, while the amplification rate turns to be 2.4~2.5. By conservative estimates, the time resolution is expected to reach 245 fs. (11 refs.)Main Heading: Streak camerasControlled terms: Cathodes - Electrons - Focusing - Monte Carlo methods - PhotoelectricityUncontrolled terms: Focusing length - Spatial resolution - Streak tubes - Time resolution - Traveling waveClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 704.1 Electric Components - 711.1 Electromagnetic Waves in Different Media - 741.1 Light/Optics - 742.2 Photographic Equipment - 922.2 Mathematical Statistics

Database: Compendex

Local coordinate concept factorization for image representation

Liu, Haifeng1; Yang, Zheng1; Yang, Ji1; Wu, Zhaohui1; Li, Xuelong2 Source: IEEE Transactions on Neural Networks and Learning Systems, v 25, n 6, p 1071-1082, June 2014

; ISSN: 2162237X, E-ISSN: 21622388; DOI: 10.1109/TNNLS.2013.2286093; Article number: 6650088;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Computer Science, Zhejiang University, Hangzhou, Zhejiang 310058, China2 Center for OPTical IMagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Learning sparse representation of high-dimensional data is a state-of-the-art method for modeling data. Matrix factorization-based techniques, such as nonnegative matrix factorization and concept factorization (CF), have shown great advantages in this area, especially useful for image representation. Both of them are linear learning problems and lead to a sparse representation of the images. However, the sparsity obtained by these methods does not always satisfy locality conditions. For example, the learned new basis vectors may be relatively far away from the original data. Thus, we may not be able to achieve the optimal performance when using the new representation for other learning tasks, such as classification and clustering. In this paper, we introduce a locality constraint into the traditional CF. By requiring the concepts (basis vectors) to be as close to the original data points as possible, each datum can be represented by a linear combination of only a few basis concepts. Thus, our method is able to achieve sparsity and locality simultaneously. We analyze the complexity of our novel algorithm and demonstrate the effectiveness in comparison with the state-of-the-art approaches through a set of evaluations based on real-world applications. © 2012 IEEE. (41 refs.)Main Heading: FactorizationControlled terms: Algorithms - Matrix algebraUncontrolled terms: Classification and clustering - Data representations - Dimensionality reduction - Image clustering - Matrix factorizations - Nonnegative matrix factorization - State-of-the-art approach - State-of-the-art methodsClassification Code: 921 Mathematics - 921.1 Algebra

Database: Compendex

2.85 μm fluorescence of Ho-doped water-free fluorotellurite glasses

He, Jianli1, 2; Zhou, Zhiguang1; Zhan, Huan1, 2; Zhang, Aidong1; Lin, Aoxiang1 Source: Journal of Luminescence, v 145, p 507-511, 2014

; ISSN: 00222313; DOI: 10.1016/j.jlumin.2013.08.020;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xian 710119, China2 Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049, China

Abstract: Holmium doped fluorotellurite glasses with composition of xHo <inf>2</inf>O<inf>3</inf> (wt%)+60TeO<inf>2</inf>-30ZnF<inf>2</inf>-10NaF (mol%) (xHo-TZNF60, x=0.50-1.50) were synthesized by physical and chemical dehydration technique (PCDH) and characterized as candidates of fiber laser glasses. Intense 2.85 μm fluorescence (Ho3+: 5I <inf>6</inf>&rarr5I<inf>7</inf>) was observed experimentally when excited at 1163 nm. It is attributed to low phonon energy of fluoride component and water-free characteristic (α<inf>OH</inf>=0.027 cm-1). Ho-TZNF glass possess a large simulated emission cross-section of 1.51×10-20 cm2, a long fluorescence lifetime of ~0.81 ms (1/e time of the initial part of non-exponential decay curve) and a broad transparent window of 2.1-4.2 μm. Among all the compositions of glass samples, 1.00Ho-TZNF60 is the optimized one, and thus is proposed to be the most potential material for 3.0 μm fiber laser. © 2013 Elsevier B.V. (25 refs.)Main Heading: GlassControlled terms: Fiber lasers - Fiber optics - Fluorescence - Infrared radiationUncontrolled terms: Fluorescence lifetimes - Fluoro-tellurite glass - Glass samples - Low phonon energies - Nonexponential decays - Potential materials - Rare earth doped materials - Simulated emissionClassification Code: 741.1 Light/Optics - 741.1.2 Fiber Optics - 812.3 Glass

Database: Compendex

Locality and similarity preserving embedding for feature selection

Fang, Xiaozhao1; Xu, Yong1, 2; Li, Xuelong3; Fan, Zizhu1; Liu, Hong4; Chen, Yan5 Source: Neurocomputing, v 128, p 304-315, March 27, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.08.040;

Publisher: ElsevierAuthor affiliation: 1 Bio-Computing Research Center, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, Guangdong, China2 Key Laboratory of Network Oriented Intelligent Computation, Shenzhen 518055, Guangdong, China3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China4 Engineering Lab on Intelligent Perception for Internet of Things, Shenzhen Graduate School, Peking University, Shenzhen 518055, Guangdong, China5 Shenzhen Sunwin Intelligent Co., Ltd, Shenzhen 518057, Guangdong, China

Abstract: Feature selection (FS) methods have commonly been used as a main way to select the relevant features. In this paper, we propose a novel unsupervised FS method, i.e., locality and similarity preserving embedding (LSPE) for feature selection. Specifically, the nearest neighbor graph is firstly constructed to preserve the locality structure of data points, and then this locality structure is mapped to the reconstruction coefficients such that the similarity among these data points is preserved. Moreover, the sparsity derived by the locality is also preserved. Finally, the low dimensional embedding of the sparse reconstruction is evaluated to best preserve the locality and similarity. We impose &ell;<inf>2,1</inf>-norm on the transformation matrix to achieve row-sparsity, which allows us to select relevant features and learn the embedding simultaneously. The selected features have good stability due to the locality and similarity preserving, and more importantly, they contain natural discriminating information even if no class labels are provided. We present the optimization algorithm and analysis of convergence of the proposed method. The extensive experimental results show the effectiveness of the proposed method. © 2013 Elsevier B.V. (58 refs.)Main Heading: OptimizationControlled terms: Algorithms - Feature extraction - Linear transformationsUncontrolled terms: Discriminating information - Low dimensional embedding - Nearest neighbors - Optimization algorithms - Relevant features - Similarity preserving - Sparse reconstruction - Transformation matricesClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 921 Mathematics

Database: Compendex

A unified learning framework for single image super-resolution

Yu, Jifei1; Gao, Xinbo1; Tao, Dacheng2; Li, Xuelong3; Zhang, Kaibing4 Source: IEEE Transactions on Neural Networks and Learning Systems, v 25, n 4, p 780-792, April 2014

; ISSN: 2162237X, E-ISSN: 21622388; DOI: 10.1109/TNNLS.2013.2281313; Article number: 6671477;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic Engineering, Xidian University, Xi'an 710071, China2 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology Sydney, Ultimo, NSW 2007, Australia3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China4 School of Computer and Information Science, Hubei Engineering University, Xiaogan 432000, China

Abstract: It has been widely acknowledged that learning- and reconstruction-based super-resolution (SR) methods are effective to generate a high-resolution (HR) image from a single low-resolution (LR) input. However, learning-based methods are prone to introduce unexpected details into resultant HR images. Although reconstruction-based methods do not generate obvious artifacts, they tend to blur fine details and end up with unnatural results. In this paper, we propose a new SR framework that seamlessly integrates learning- and reconstruction-based methods for single image SR to: 1) avoid unexpected artifacts introduced by learning-based SR and 2) restore the missing high-frequency details smoothed by reconstruction-based SR. This integrated framework learns a single dictionary from the LR input instead of from external images to hallucinate details, embeds nonlocal means filter in the reconstruction-based SR to enhance edges and suppress artifacts, and gradually magnifies the LR input to the desired high-quality SR result. We demonstrate both visually and quantitatively that the proposed framework produces better results than previous methods from the literature. © 2012 IEEE. (44 refs.)Main Heading: Image reconstructionControlled terms: Optical resolving powerUncontrolled terms: Example learning-based - High resolution image - Image super-resolution - Integrated frameworks - Learning-based methods - Non- local means filters - reconstruction-based - Self-similaritiesClassification Code: 741 Light, Optics and Optical Devices - 741.1 Light/Optics

Database: Compendex

Improved joint demosaicking-zooming algorithm and its hardware design

Li, Hua1; Zhu, Bo2, 3 Source: Guangdianzi Jiguang/Journal of Optoelectronics Laser, v 25, n 1, p 199-206, January 2014; Language: Chinese

; ISSN: 10050086;

Publisher: Board of Optronics LasersAuthor affiliation: 1 Shangluo University, Shangluo 726000, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 The Joint Laboratory for Space Vision of XJTU-XIOPM, Xi'an 710049, China

Abstract: In order to obtain higher resolution full color image from Bayer CFA structure image directly, this paper presents a new joint demosaicking and zooming algorithm for digital camera equipped with a single CCD/CMOS sensor. We firstly extract GH and GV components of each pixel from mosaicking image through horizontal and vertical interpolations, respectively, and then we calculate and compare the horizontal chrominance gradient and the vertical one for choosing the missing G from GH and GV. By exploiting the high spectral-spatial correlations between color channels, we compute the two color difference images R-G and B-G to reduce the demosaicking and zooming errors. Next, we obtain the horizontal GzoomH and vertical GzoomV of each pixel, and also choose the missing zoomed Gzoom by calculating and comparing the chrominance gradient. Finally, the enlarged red and blue channels are obtained by adding the corresponding enlarged R-G and B-G color difference images to the enlarged green channel. Experimental results prove that the proposed algorithm outperforms some state-of-the-art demosaicking-zooming methods in both peak signal-to-noise ratio (PSNR) measure and visual quality. Furthermore, computational cost of the algorithm is low and it can be hardware processed in real time. Now, the proposed algorithm is implemented on Xilinx FPGA and used in camera system, and the perfect restoration quality and effectiveness meet the requirement of system design. (15 refs.)Main Heading: ColorControlled terms: Algorithms - Color image processing - Colorimetry - Field programmable gate arrays (FPGA) - Hardware - PixelsUncontrolled terms: Bayer pattern images - Computational costs - Demosaicking - Full color images - Peak signal-to-noise ratio - Restoration quality - Zooming - Zooming algorithmsClassification Code: 941.4 Optical Variables Measurements - 921 Mathematics - 741.1 Light/Optics - 723.5 Computer Applications - 723 Computer Software, Data Handling and Applications - 721.3 Computer Circuits - 605 Small Tools and Hardware

Database: Compendex

Enhanced near infrared luminescence efficiency of ligand-free LaF <inf>3</inf>:Nd/LaF<inf>3</inf> core/shell nanocrystals in solvent dispersion

Cui, Xiaoxia1; Guo, Haitao1; Hou, Chaoqi1; Gao, Fei1; Wei, Wei1, 2; Peng, Bo1, 2 Source: Journal of Luminescence, v 154, p 155-159, October 2014

; ISSN: 00222313; DOI: 10.1016/j.jlumin.2014.04.019;

Publisher: ElsevierAuthor affiliation: 1 Chinese Academy of Science (CAS), Xi'An Institute of Optics and Precision Mechanics, State Key Laboratory of Transient Optics and Photonics, No.17 Xinxi Road, Xi'an, Shaanxi 710119, China2 Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210003, China

Abstract: A variety of ligand-free LaF<inf>3</inf>:Nd/LaF<inf>3</inf> core/shell nanocrystals with high quantum efficiency, great dispersibility and low quench ratio was prepared by a simple solvothermal method. Their phase and morphologies were characterized by X-ray diffraction (XRD) and transmission electron microscope (TEM). The optical properties of the samples prepared under different times were investigated. The core/shell nanocrystals have great dispersibility concentration (312 mg/mL) in dimethyl sulfoxide (DMSO)/tetrabromoethane solvents. These transparent colloidal solution exhibits enhanced high quantum efficiency (61.2%) at 1057 nm. Therefore, the LaF<inf>3</inf>:Nd/LaF<inf>3</inf> core/shell nanocrystals with excellent near infrared to near infrared (NIR-to-NIR) fluorescence are a promising candidate for luminescence material in liquid media. © 2014 Elsevier B.V. (18 refs.)Main Heading: Infrared devicesControlled terms: Dimethyl sulfoxide - Dispersions - Nanocrystals - Organic solvents - Quantum efficiency - Transmission electron microscopy - X ray diffractionUncontrolled terms: Core shell - Core/shell nanocrystals - Dimethyl sulfoxide (DMSO) - High quantum efficiency - Luminescence material - Near Infrared - Near infrared luminescence - Solvothermal methodClassification Code: 741.3 Optical Devices and Systems - 761 Nanotechnology - 803 Chemical Agents and Basic Industrial Chemicals - 931.3 Atomic and Molecular Physics - 931.4 Quantum Theory; Quantum Mechanics - 951 Materials Science

Database: Compendex

Image quality evaluation and analysis in Fourier telescopy for laboratory demonstration

Zhang, Yu1, 2; Luo, Xiu-Juan1; Xia, Ai-Li1; Cao, Bei1; Cheng, Zhi-Yuan1, 2; Zeng, Zhi-Hong1, 2; Si, Qing-Dan1, 2; Wang, Bao-Feng1, 2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 3, March 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144303.0311001; Article number: 0311001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Institute of Optics and Precision Mechanism of Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Science, Beijing 100049, China

Abstract: Strehl ratio is often used as a method for evaluation of the Fourier telescope imaging quality. This method computes the correlation of the reconstructed image and the ideal image to evaluate the image quality, which is mainly applicable in the computer simulation analysis. However, the object to be observed may be unknow in the real world, which means there is no ideal image for use. Based on laboratory imaging data, the feasibility of the non-reference image evaluation method applied to Fourier telescopy is proposed and analyzed. The gray mean grads (GMG) method and Laplacian Sum(LS) are adopted to describe how much detail information the reconstructed image has. For the same object, Employ Strehl ratio and GMG, LS to evaluate the simulated image and the laboratory imaging result, respectively. Statistical results show that the two kinds of evaluations are identical in changing tendency. It proves the GMG and LS methods are applicable in Fourier telescopy as a non-reference image evaluation. (12 refs.)Main Heading: Image reconstructionControlled terms: Computer simulation - Fourier transforms - Image quality - Laplace transformsUncontrolled terms: Beat frequency - Fourier telescopy - Image evaluation - Laplacians - Strehl RatioClassification Code: 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 921.3 Mathematical Transformations

Database: Compendex

Optical system design of broadband astigmatism-free Czerny-turner spectrometer

Zhao, Yiyi1, 2; Yang, Jianfeng1; Xue, Bin1; Yan, Xingtao1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 4, p 1182-1187, April 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: For the development trend of miniaturization and high-resolution of spectrometer, an optical design with a simple structure, broadband, astigmatism-corrected micro spectrometer was designed. The principle and correction method of the aberration of crossed beam Czerny-turner spectrometer were analyzed in detail. The broadband astigmatism-corrected theory equations using cylindrical lens were deduced. For example, a micro spectrometer operating in 300-900 nm with an object NA of 0.08 has been designed. This spectrometer adopted crossed beam structure to minish its volume and used a cylindrical lens to remove astigmatism over the full bandwidth. The analyzed results demonstrated that this spectrometer with compact configuration and small volume corrected the astigmatism in the wide spectral region. The resolution of the spectrometer was better than 0.5 nm in the whole spectral region. (12 refs.)Main Heading: SpectrometersControlled terms: Optical designUncontrolled terms: Astigmatism-corrected - Broadband - Correction method - Cylindrical lens - Czerny-Turner spectrometer - Development trends - Micro-spectrometer - Simple structuresClassification Code: 741.1 Light/Optics - 801 Chemistry

Database: Compendex

Low-timing-jitter mode-locked fiber laser based on graphene oxide PVA thin film as saturable absorber

Wu, Kan1; Li, Xiaohui2; Wang, Yonggang3; Wang, Qijie2; Shum, Perry Ping2; Chen, Jianping1 Source: Asia Communications and Photonics Conference, ACPC 2014, November 14, 2014; ISBN-13: 9781557528520; Conference: Asia Communications and Photonics Conference, ACPC 2014, November 11, 2014 - November 14, 2014; Sponsor: CIC; COS; IEEE Photonics Society; OSA; SPIE;

Publisher: Optical Society of America (OSA)Author affiliation: 1 State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, China2 OPTIMUS, Centre of Excellence for Photonics, School of Electrical and Electronic Engineering, Nanyang Technological Universityx, 50 Nanyang Ave, Singapore3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We demonstrate a mode-locked fiber laser based on graphene oxide saturable absorber at 1550nm. The laser has a timing jitter of 53fs (100Hz to 100kHz). The contribution from the slow saturable absorber is also investigated. © OSA 2014. (4 refs.)Main Heading: Mode-locked fiber lasersControlled terms: Fiber lasers - Graphene - Locks (fasteners) - Photonics - Saturable absorbers - Timing jitterUncontrolled terms: Graphene oxides - Low timing jitterClassification Code: 601.3 Mechanisms - 712 Electronic and Thermionic Materials - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 744 Lasers - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Calibrating tracing errors for space-used telescope by coordinate transfor

Cui, Kai1; Liu, Zhaohui1; Li, Zhiguo1; Gao, Xiong1; Xie, Youjin1; Wang, Zhenyu1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, p 151-156, December 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: For better testing and calibrating the space-used telescope, a novel calculating model was introduced to simulate tracing process of the satellite. The coordinate transform theory was used for the indoor rotating target, the result was coincident with the spherical trigonometry. A model was deduced to illustrate the relationship between the tracing errors and the position errors of detecting system and the telescope gyration centre. The result showed that, a position error of 0.2 m in the vertical axis direction simply causing a constant elevation angle tracing error of 5.658 74°, without any influence on other tracing performance. An error of 0.002 m in the horizontal axis direction caused coupling tracing errors both in azimuth and elevation measurements, the azimuth angle tracing error ranged between 0.056 78°~0.139 25°, azimuth angular velocity error was 0.007 01° per second, the azimuth angular acceleration error was 0.002 56 degree per second square, while the elevation angle tracing error was about 10-4order of magnitude, and the angular velocity and angular acceleration was about 10-6order of magnitude. The tracing performance was independent of position error in the collimation axis direction. This conclusion provides reference for testing and assembling space-used telescope. ©, 2014, Chinese Society of Astronautics. All right reserved. (10 refs.)Main Heading: ErrorsControlled terms: Angular velocity - TelescopesUncontrolled terms: Angular acceleration - Calculating model - Calibrating - Co-ordinate transform - Detecting systems - Horizontal axis - Position errors - Tracing processClassification Code: 657 Space Physics - 731 Automatic Control Principles and Applications - 921 Mathematics - 931.1 Mechanics

Database: Compendex

The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station

Zhang, S.N.1; Adriani, O.2; Albergo, S.2; Ambrosi, G.2; An, Q.3; Bao, T.W.1; Battiston, R.4; Bi, X.J.1; Cao, Z.1; Chai, J.Y.1; Chang, J.5; Chen, G.M.1; Chen, Y.6; Cui, X.H.7; Dai, Z.G.6; D'Alessandro, R.2; Dong, Y.W.1; Fan, Y.Z.5; Feng, C.Q.3; Feng, H.8; Feng, Z.Y.1; Gao, X.H.9; Gargano, F.2; Giglietto, N.2; Gou, Q.B.1; Guo, Y.Q.1; Hu, B.L.9; Hu, H.B.1; He, H.H.1; Huang, G.S.3; Huang, J.1; Huang, Y.F.6; Li, H.1; Li, L.1; Li, Y.G.1; Li, Z.10; Liang, E.W.11; Liu, H.1; Liu, J.B.3; Liu, J.T.1; Liu, S.B.3; Liu, S.M.5; Liu, X.1; Lu, J.G.1; Mazziotta, M.N.2; Mori, N.2; Orsi, S.12; Pearce, M.13; Pohl, M.14; Quan, Z.1; Ryde, F.13; Shi, H.L.1; Spillantini, P.2; Su, M.15; Sun, J.C.1; Sun, X.L.1; Tang, Z.C.1; Walter, R.12; Wang, J.C.16; Wang, J.M.1; Wang, L.9; Wang, R.J.1; Wang, X.L.3; Wang, X.Y.6; Wang, Z.G.24; Wei, D.M.5; Wu, B.B.1; Wu, J.17; Wu, X.12; Wu, X.F.5; Xia, J.Q.1; Xiao, H.L.22; Xu, H.H.1; Xu, M.23; Xu, Z.Z.3; Yan, H.R.10; Yin, P.F.1; Yu, Y.W.18; Yuan, Q.1; Zha, M.1; Zhang, L.19; Zhang, L.20; Zhang, L.Y.1; Zhang, Y.21; Zhang, Y.J.1; Zhang, Y.L.3; Zhao, Z.G.3 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9144, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9780819496126; DOI: 10.1117/12.2055280; Article number: 91440X; Conference: Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, June 22, 2014 - June 26, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China2 Center of Experimental Physics, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China3 Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China4 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China5 Department of Modern Physics, University of Science and Technology of China, Hefei, China6 School of Astronomy and Space Science, Nanjing University, Nanjing, China7 Department of Astronomy, Peking University, Beijing, China8 Department of Engineering Physics, Tsinghua University, Beijing, China9 National Astronomical Observatories, Chinese Academy of Sciences, Beijing, China10 Yunnan Astronomical Observatory, Chinese Academy of Sciences, Kunming, China11 Department of Astronomy, Yunan University, Kunming, China12 Department of Physics, Guangxi University, Nanning, China13 Institute of Astrophysics, Central China Normal University, Wuhan, China14 Department of Physics, China University of Geosciences, Wuhan, China15 Istituto Nazionale di Fisica Nucleare, Bari, Italy16 INFN Sezione di Firenze, Florence, Italy17 Department of Physics and Astronomy, University of Florence, Florence, Italy18 INFN Sezione di Perugia, Perugia, Italy19 INFN-TIFPA and Universitc di Trento, Trento, Italy20 INFN Sezione di Catania and Universitc di Catania, Catania, Italy21 DPNC, University of Geneva, Geneva, Switzerland22 ISDC Data Centre for Astrophysics, University of Geneva, Geneva, Switzerland23 Department of Physics, Royal Institute of Technology (KTH), Stockholm, Sweden24 Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge; MA, United States

Abstract: The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO. © 2014 SPIE. (28 refs.)Main Heading: Gamma raysControlled terms: Calorimeters - Cosmic ray measurement - Cosmic rays - Cosmology - Electrons - Galaxies - Optical fibers - Silicon - Space stations - Space telescopesUncontrolled terms: Composition measurements - Dark matter - Dark matter searches - Directional measurement - Microstrip silicon tracker - Microstripes - Scientific objectives - Space experimentsClassification Code: 656.1 Space Flight - 657 Space Physics - 657.2 Extraterrestrial Physics and Stellar Phenomena - 701.1 Electricity: Basic Concepts and Phenomena - 712.1.1 Single Element Semiconducting Materials - 741.1.2 Fiber Optics - 801 Chemistry - 932 High Energy Physics; Nuclear Physics; Plasma Physics - 932.1 High Energy Physics

Database: Compendex

Generation of bidirectional stretched pulses in a nanotube-mode-locked fiber laser

Yao, Xiankun1 Source: Applied Optics, v 53, n 1, p 27-31, January 1, 2014

; ISSN: 1559128X, E-ISSN: 15394522; DOI: 10.1364/AO.53.000027;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The bidirectional stretched pulses in a nanotube-based erbium-doped fiber laser are observed experimentally for the first time to our best knowledge. The proposed fiber laser generates two stable pulse trains in opposite directions with different central wavelengths, pulse widths, and repetition rates. In addition, the bidirectional operations with the same central wavelengths are also demonstrated by changing the polarization controller and pump power. Experimental results suggest that the cavity asymmetries together with the fiber birefringence play key roles in the formation of these unique features. © 2014 Optical Society of America. (45 refs.)Main Heading: Pulse generatorsControlled terms: Fiber lasers - Nanotubes - Pulse repetition rateUncontrolled terms: Bidirectional operation - Central wavelength - Erbium doped fiber laser - Fiber birefringence - Polarization controllers - Pulse train - Repetition rate - Unique featuresClassification Code: 713.4 Pulse Circuits - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology

Database: Compendex

Welcome from the program committee chairs

Li, Xuelong1; Cai, Hongming2 Source: PIC 2014 - Proceedings of 2014 IEEE International Conference on Progress in Informatics and Computing, December 2, 2014; ISBN-13: 9781479920334; DOI: 10.1109/PIC.2014.6972423; Article number: 6972423; Conference: 2014 2nd IEEE International Conference on Progress in Informatics and Computing, PIC 2014, May 16, 2014 - May 18, 2014; Sponsor: Donghua University; IEEE Beijing Section; Shanghai Jiao Tong University; Shanghai University of Finance and Economics; University of Technology, Sydney (UTS);

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, China2 Shanghai Jiao Tong University, China

Database: Compendex

Visibility enhancement of hazy images based on a universal polarimetric imaging method

Liang, Jian1, 2; Ren, Li-Yong1; Ju, Hai-Juan1; Qu, En-Shi1; Wang, Ying-Li1 Source: Journal of Applied Physics, v 116, n 17, November 7, 2014

; ISSN: 00218979, E-ISSN: 10897550; DOI: 10.1063/1.4901244; Article number: 173107;

Publisher: American Institute of Physics Inc.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Enhancing the visibility of images taken in the hazy weather is important in many applications. Among many dehazing methods, those based on polarimetric imaging techniques have several advantages, such as ease of keeping detailed information, low cost, and high efficiency. In this paper, we propose a novel and robust dehazing algorithm based on polarimetric imaging. By introducing the orientation-angle information from the Stokes matrix, all the parameters used in dehazing performance can be effectively, precisely and automatically estimated, and no additional human-computer interaction is needed. Besides, this method can also be used in handling hazy images without sky region. Experimental results show that such a method can greatly enhance the visibility of hazy images. © 2014 AIP Publishing LLC. (17 refs.)Main Heading: DemulsificationControlled terms: Human computer interaction - Imaging techniques - Polarimeters - VisibilityUncontrolled terms: Angle information - Dehazing - Low costs - Polarimetric imaging - Stokes matricesClassification Code: 461.4 Ergonomics and Human Factors Engineering - 513.1 Petroleum Refining, General - 741 Light, Optics and Optical Devices - 741.2 Vision - 746 Imaging Techniques - 941.3 Optical Instruments

Database: Compendex

The co-simulation of airborne stable platform based on Adams/Simulink

Dong, Qiang1, 2; Yang, Xiaoxu1; Han, Junfeng1; Li, Yan1 Source: Lecture Notes in Electrical Engineering, v 323, p 49-57, 2014

; ISSN: 18761100, E-ISSN: 18761119; ISBN-13: 9783662446867; DOI: 10.1007/978-3-662-44687-4_5; Conference: 27th Conference of Spacecraft TT and C Technology, November 9, 2014 - November 12, 2014;

Publisher: Springer VerlagAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xian, China2 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Science, Beijing, China

Abstract: This paper proposes an approach to design a simulation method based on Adams and Simulink to improve performance of the stable platform. First, this paper gives an Adams/Simulink co-simulation method of airborne stable platform. Second, it designs mechanic model in Adams and control model in Simulink. Finally, simulate mechanic and control model of airborne stable platform, the simulation result shows that the co-simulation of Adams and Simulink is feasible. In the Adams model, it designs different error factors as follows: friction disturbance, motor disturbance, aircraft vibration disturbance and gear backlash. The simulation result is further close to the actual situation. Therefore, the co-simulation method of this paper is better than traditional simulink method. The design of co-simulation has guiding significance for improving the mechanic and control module of airborne stable platform. (9 refs.)Main Heading: Computer simulationControlled terms: Aircraft control - Design - Mechanics - Spacecraft - Vibrations (mechanical)Uncontrolled terms: Adams - Cosimulation - Friction disturbance - Guiding significances - Improve performance - Simulink - Stable platform - Vibration disturbancesClassification Code: 408 Structural Design - 652 Aircraft and Avionics - 655.1 Spacecraft, General - 723.5 Computer Applications - 931.1 Mechanics

Database: Compendex

A frame correlation and Kalman filtering algorithm for space debris detection

Xi, Jiangbo1, 2; Wen, Desheng1; Song, Zongxi1; Gao, Wei1; Kang, Menghua1, 2; Mou, Jiao1, 2; Lu, Hao1, 2; Pang, Peng1, 2 Source: Journal of Information and Computational Science, v 11, n 15, p 5317-5325, October 10, 2014

; ISSN: 15487741; DOI: 10.12733/jics20104688;

Publisher: Binary Information PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: An algorithm with frame correlative detection and Kalman filtering tracking was proposed to detect the multiple space debris in the optical astronomical images. It can reduce the large amount of calculation of sequential images. When the debris is covered by the star or disappears in view sight temporarily, the debris position can be estimated by Kalman filtering. At the end of the paper, a detection and tracking simulation is carried out. The results indicate that our algorithm is very effective for the space debris detection and tracking. Copyright © 2014 Binary Information Press. (12 refs.)Main Heading: Space debrisControlled terms: Algorithms - Kalman filters - Tracking (position)Uncontrolled terms: Astronomical images - Detection and tracking - Frame correlations - Kalman filtering algorithms - Kalman-filtering - Large amounts - Sequential imagesClassification Code: 655.1 Spacecraft, General - 716.2 Radar Systems and Equipment - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 921 Mathematics

Database: Compendex

Effect of femtosecond laser parameters on TiC ceramic micro-hole drilling

Wang, Yuqian1; Zhang, Junzhan1; Liu, Yongsheng2; Yang, Xiaojun3; Li, Weinan3; Wang, Chunhui2 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 10, October 10, 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.1003010; Article number: 1003010;

Publisher: Science PressAuthor affiliation: 1 School of Materials and Mineral Resources, Xi'an University of Architecture and Technology, Xi'an; Shaanxi, China2 Key Laboratory of Science and technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an; Shaanxi, China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: Drilling micro-holes in TiC ceramic with femtosecond laser in different laser fluence and assisted gas pressure has been demonstrated. Scanning electron microscope (SEM), micrometer X-ray 3D imaging system (Micro-CT) and X-ray photoelectron spectroscopy (XPS) are used to investigate the morphology and chemical bonds of micro-holes. The results show that the circularities of micro-holes at the entry are not less than 99% when the laser fluence varies. The circularities of micro-holes at the exit increase as the laser fluence grows, then it tend to be stable. The maximum value of the circularity at the exit is 95%. The taper of micro-holes increases with the assisted gas pressure. When the laser fluence is 0.51 J/mm2, the taper of micro-holes drilled with 0.3 MPa gas pressure is the best, its long axis taper is -0.13° and the short axis taper is 0.77°. C-C bonds and Ti-C bonds rupture while debris which contains metal Ti, Ti<inf>2</inf>O<inf>3</inf> and TiO<inf>2</inf> forms around the micro-holes during laser drilling. Lastly, the mechanism of interactions between laser beam and materials is discussed. (42 refs.)Main Heading: X ray photoelectron spectroscopyControlled terms: Bond strength (chemical) - Ceramic materials - Computerized tomography - Imaging systems - Laser beams - Scanning electron microscopy - Titanium carbide - Ultrashort pulses - Well drillingUncontrolled terms: Gas pressures - Laser fluences - Micro holes - TiC ceramic - Ultrafast opticsClassification Code: 446.1 Water Supply Systems - 531 Metallurgy and Metallography - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 744.1 Lasers, General - 744.8 Laser Beam Interactions - 746 Imaging Techniques - 801 Chemistry - 801.4 Physical Chemistry - 812.1 Ceramics - 812.2 Refractories

Database: Compendex

Design and simulation of the adaptive optics system based on mixed H<inf>2</inf>/H<inf>∞</inf> control

Zhao, Xin1, 2; Ma, Cai-Wen1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 12, December 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144312.1201003; Article number: 1201003;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: To achieve small residual wavefront gradient tilt corrected by the adaptive optics system and good robust stability of the system, a mixed H<inf>2</inf>/H<inf>∞</inf> control method for the adaptive optics system was proposed. In order to verify the control performance, the atmospheric turbulence wavefront gradient tilt was simulated, and the residual wavefront gradient tilt corrected by the adaptive optics wavefront gradient tilt correction test platform with the mixed H<inf>2</inf>/H<inf>∞</inf> controller and by the one with the classic integral controller was compared. The robust stability of the two systems was compared as well. The result demonstrated that the test platform with the mixed H<inf>2</inf>/H<inf>∞</inf> controller achieved not only smaller residual wavefront gradient tilt but also better robust stability compared to the one with the classic integral controller, and proved the efficiency of the mixed H<inf>2</inf>/H<inf>∞</inf> control method for the adaptive optics system. (21 refs.)Main Heading: Adaptive opticsControlled terms: Adaptive control systems - Atmospheric thermodynamics - Atmospheric turbulence - Control system stability - Control systems - Controllers - Robust control - System stability - WavefrontsUncontrolled terms: Adaptive optics systems - Control performance - Design and simulation - Integral controllers - Optimal controls - Robust stability - Simulation - Wavefront gradientsClassification Code: 443.1 Atmospheric Properties - 711 Electromagnetic Waves - 731 Automatic Control Principles and Applications - 732.1 Control Equipment

Database: Compendex

An alignment method of off-axis aspheric mirror

Han, Juan1, 2; Duan, Jiayou1; Chen, Jianjun1, 3; Wu, Mengyuan1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, September 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.s122002; Article number: s122002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China2 School of Physics and Optoelectronic Engineering, Xidian University, Xi'an; Shaanxi, China3 University of Chinese Academy of Sciences, Beijing, China

Abstract: In order to realize the accurate position of an off-axis aspheric surface in optical alignment, it is necessary to strictly control the six degrees of freedom, especially the two degrees of freedom that affect lateral displacement and tilts angle. But it's very difficult to obtain the above two accurate values using general off-axis aspheric surface measurement technique, so it's same difficult to realize its precise alignment. The article introduces a new method that applying the close relationship between the center image of radius of curvature and the optical axis of the self-regulating instrument, and by using the precise measurement, the purpose of measuring lateral displacement and tilts angle is achieved. Experiments show that the error of lateral displacement is less than 0.05 mm, the error of tilts angle is less than 10″, and the wave aberration root mean square is equal to 0.02λ (λ=632.8 nm). It can obtain the perfect image and realize the precise alignment of the off-axis aspheric mirror by using this method. (16 refs.)Main Heading: Displacement measurementControlled terms: Aspherics - Degrees of freedom (mechanics) - Measurements - Mechanics - Mirrors - Surface measurementUncontrolled terms: Lateral displacements - Off-axis aspheric - Optical alignments - Radius of curvature - Tilts angleClassification Code: 741.3 Optical Devices and Systems - 931.1 Mechanics - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 943.2 Mechanical Variables Measurements - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

A modified artificial bee colony algorithm based on search space division and disruptive selection strategy

He, Zhen-An1, 2, 3; Ma, Caiwen1; Wang, Xianhong1; Li, Lei4; Wang, Ying4; Zhao, Yuan1, 2, 5; Guo, Huinan1 Source: Mathematical Problems in Engineering, v 2014, 2014

; ISSN: 1024123X, E-ISSN: 15635147; DOI: 10.1155/2014/432654; Article number: 432654;

Publisher: Hindawi Publishing CorporationAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi, China2 University of Chinese Academy of Sciences, Beijing, China3 Unit 96165 of the Chinese People's Liberation Army, Shangrao, Jiangxi, China4 North Optoelectronic Stock Ltd., Xi'an, Shaanxi, China5 Engineering University of the Chinese Armed Police Force, Xi'an, Shaanxi, China

Abstract: Artificial bee colony (ABC) algorithm has attracted much attention and has been applied to many scientific and engineering applications in recent years. However, there are still some insufficiencies in ABC algorithm such as poor quality of initial solution, slow convergence, premature, and low precision, which hamper the further development and application of ABC. In order to further improve the performance of ABC, we first proposed a novel initialization method called search space division (SSD), which provided high quality of initial solutions. And then, a disruptive selection strategy was used to improve population diversity. Moreover, in order to accelerate convergence rate, we changed the definition of the scout bee phase. In addition, we designed two types of experiments to testify our proposed algorithm. On the one hand, we conducted experiments to make sure how much each modification makes contribution to improving the performance of ABC. On the other hand, comprehensive experiments were performed to prove the superiority of our proposed algorithm. The experimental results indicate that SDABC significantly outperforms other ABCs, contributing to higher solution accuracy, faster convergence speed, and stronger algorithm stability. (26 refs.)Main Heading: Evolutionary algorithmsControlled terms: Experiments - OptimizationUncontrolled terms: Algorithm stability - Artificial bee colony algorithms - Artificial bee colony algorithms (ABC) - Development and applications - Faster convergence - Initialization methods - Population diversity - Scientific and engineering applicationsClassification Code: 723 Computer Software, Data Handling and Applications - 901.3 Engineering Research - 921 Mathematics - 921.5 Optimization Techniques

Database: Compendex

Tunable terahertz Kerr switching based on nonlinear polarization rotation in silicon waveguide

Mou, Miaoli1; Liu, Hongjun1; Huang, Nan1; Sun, Qibing1; Wang, Zhaolu1 Source: Applied Optics, n 12, p 2741-2747, April 20, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.002741;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics Technology, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, China

Abstract: A compact and widely tunable terahertz (THz) all-optical Kerr switching using nonlinear polarization rotation generated by cross-phase modulation in a silicon waveguide is theoretically proposed. A switching efficiency of 83% is obtained when a -phase shift difference between the TE and TM polarization components of the continuous-wave THz signal is achieved. Moreover, the tuning range of the THz switching is from 7.69 to 10 THz through changing the pump power. This THz all-optical switching has potential applications in THz communications and other THz switchable devices. © 2014 Optical Society of America. (35 refs.)Main Heading: Terahertz wavesControlled terms: Nonlinear optics - Optical switches - Phase shift - Phase shifters - Polarization - Silicon - Switching - WaveguidesUncontrolled terms: All-optical switching - Continuous-wave thz - Cross-phase modulations - Nonlinear polarization rotation - Silicon waveguide - Switching efficiency - THz communications - TM polarizationClassification Code: 703.1 Electric Networks - 711 Electromagnetic Waves - 711.1 Electromagnetic Waves in Different Media - 712.1.1 Single Element Semiconducting Materials - 714.3 Waveguides - 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 741 Light, Optics and Optical Devices - 942.2 Electric Variables Measurements

Database: Compendex

A multi-focus image adaptive fusion method based on comprehensive index

Lu, Hao1, 2; Song, Zongxi1; Gao, Wei1; Wang, Qi1, 2; Xi, Jiangbo1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9284, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413595; DOI: 10.1117/12.2069158; Article number: 92840N; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: As the focusing range of optical imaging system is generally limited, it is difficult to make all the objects of the same scene clearly shown in one image. Besides, a case usually rose that the fused image with a high entropy, however, is not satisfying for vision effect. In this paper, a new method of multi-focus image fusion based on adaptive dividing blocks using comprehensive index was proposed, in which the comprehensive index was on basis of spatial frequency and entropy. The comprehensive index is better with the higher spatial frequency and entropy. Firstly, the registered original images were divided into a series of blocks of which the sizes were proper and the same, and then the comprehensive index for each block of source images was calculated as the focus criterion function to select an optimal block for each corresponding block of the fused image. In view of the relevance between pixel and pixel in one image, the optimal blocks selected were fused with a global fusion function. Furthermore, the sum-modified-Laplacian of fused image was used as the measure function to supervise the adaptive blocking, in which the optimal block was obtained when SML of the fused image had reached a high value or the iteration had achieved the specified numbers. Finally, the optimal size of the sub-block was automatically obtained, which was used to fuse the source images. As it was shown in the experimental results, the proposed method which was simple, but more effective compared with the traditional multiscale decomposing methods such as wavelet transform, wavelet packet transform, contourlet transform and so on. At the same time, the proposed method was also superior to the method in the literature for it could remove boundary discontinuities between image blocks. Contemporarily, much more details and edges information of the source images were reserved in the fused image. (13 refs.)Main Heading: Image fusionControlled terms: Adaptive optics - Entropy - Iterative methods - Laplace transforms - Manufacture - Materials testing - Optoelectronic devices - Packet networks - Pixels - Wavelet transformsUncontrolled terms: Comprehensive indices - Contourlet transform - Criterion functions - Global fusion function - Multifocus image fusion - Optical imaging system - Sum-Modified-Laplacian - Wavelet packet transformsClassification Code: 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 537.1 Heat Treatment Processes - 641.1 Thermodynamics - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 717.2 Optical Communication Equipment - 718 Telephone Systems and Related Technologies; Line Communications - 723.2 Data Processing and Image Processing - 723.5 Computer Applications - 731.1 Control Systems - 921.3 Mathematical Transformations - 921.6 Numerical Methods - 951 Materials Science

Database: Compendex

Effects of various room temperatures on terahertz radiation via optical parametric oscillator

Huang, Nan1; Liu, Hongjun1; Sun, Qibing1 Source: Optical Engineering, v 53, n 6, June 2014

; ISSN: 00913286, E-ISSN: 15602303; DOI: 10.1117/1.OE.53.6.066112; Article number: 066112Author affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, State Key Laboratory of Transient Optics and Photonics, No. 17 Xinxi Road, Xi'an 710119, China

Abstract: A terahertz (THz)-wave parametric oscillator (TPO) pumped by a stable and single-longitudinal mode Q-switched Nd:YAG laser under various room temperatures is demonstrated. It is based on a cavity TPO architecture allowing stable single-resonance operation and low oscillation threshold. The output results, including the effects of the room temperature on this wavelength-agile TPO with a MgO:LiNbO<inf>3</inf> crystal, indicate that the performance of TPO under the lower temperature is better. We obtain a widely tunable THz-wave source in the range 104 to 226 μmvia tuning the cavity flexibly under different room temperatures. The peak power of the THz wave reaches 220 mW at the wavelength of 146.2 μm when the room temperature is 20°C. The peak power of the THz wave decreases to 48 mW when the room temperature rises from 20°C to 25°C. © 2014 Society of Photo-Optical Instrumentation Engineers. (21 refs.)Main Heading: Terahertz wavesControlled terms: Neodymium lasers - Nonlinear optics - Optical parametric oscillatorsUncontrolled terms: Lower temperatures - Oscillation threshold - Q switched Nd:YAG laser - Room temperature - Single longitudinal mode - Terahertz generation - Terahertz radiation - Wavelength-agileClassification Code: 711 Electromagnetic Waves - 741.1.1 Nonlinear Optics - 741.3 Optical Devices and Systems - 744.4 Solid State Lasers - 744.9 Laser Applications

Database: Compendex

Contrast transfer function in grating-based x-ray phase-contrast imaging

Huang, Jianheng1; Du, Yang1, 2; Lin, Danying1; Liu, Xin1; Niu, Hanben1 Source: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, v 747, p 13-18, May 21, 2014

; ISSN: 01689002; DOI: 10.1016/j.nima.2014.01.029;

Publisher: ElsevierAuthor affiliation: 1 Key Laboratory of Optoelectronics Devices and Systems, Ministry of Education and Guangdong Province, Shenzhen University, Shenzhen 518060, China2 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: x-Ray grating interferometry is a method for x-ray wave front sensing and phase-contrast imaging that has been developed over past few years. Contrast and resolution are the criteria used to specify the quality of an image. In characterizing the performance of this interferometer, the contrast transfer function is considered in this paper. The oscillatory nature of the contrast transfer function (CTF) is derived and quantified for this interferometer. The illumination source and digital detector are both considered as significant factors controlling image quality, and it can be noted that contrast and resolution in turn depends primarily on the projected intensity profile of the array source and the pixel size of the detector. Furthermore, a test pattern phantom with a well-controlled range of spatial frequencies was designed and imaging of this phantom was simulated by a computer. Contrast transfer function behavior observed in the simulated image is consistent with our theoretical CTF. This might be beneficial for the evaluation and optimization of a grating-based x-ray phase contrast imaging system. © 2014 Published by Elsevier B.V. (25 refs.)Main Heading: Transfer functionsControlled terms: Interferometers - Interferometry - Optical resolving power - X raysUncontrolled terms: Contrast transfer function - Grating interferometry - Illumination sources - Intensity profiles - Phase-contrast imaging - Simulated images - Spatial frequency - X-ray phase-contrast imagingClassification Code: 741.1 Light/Optics - 932.1 High Energy Physics - 941.3 Optical Instruments - 941.4 Optical Variables Measurements

Database: Compendex

Part-based online tracking with geometry constraint and attention selection

Fang, Jianwu1; Wang, Qi2; Yuan, Yuan1 Source: IEEE Transactions on Circuits and Systems for Video Technology, v 24, n 5, p 854-864, May 2014

; ISSN: 10518215; DOI: 10.1109/TCSVT.2013.2283646; Article number: 6612705;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Center for OPTical IMagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Xi'an, Shaanxi 710119, China2 Northwestern Polytechnical University, Xi'an, China

Abstract: Visual tracking in condition of occlusion, appearance or illumination change has been a challenging task over decades. Recently, some online trackers, based on the detection by classification framework, have achieved good performance. However, problems are still embodied in at least one of the three aspects: 1) tracking the target with a single region has poor adaptability for occlusion, appearance or illumination change; 2) lack of sample weight estimation, which may cause overfitting issue; and 3) inadequate motion model to prevent target from drifting. For tackling the above problems, this paper presents the contributions as follows: 1) a novel part-based structure is utilized in the online AdaBoost tracking; 2) attentional sample weighting and selection is tackled by introducing a weight relaxation factor, instead of treating the samples equally as traditional trackers do; and 3) a two-stage motion model, multiple parts constraint, is proposed and incorporated into the part-based structure to ensure a stable tracking. The effectiveness and efficiency of the proposed tracker is validated upon several complex video sequences, compared with seven popular online trackers. The experimental results show that the proposed tracker can achieve increased accuracy with comparable computational cost. © 2013 IEEE. (41 refs.)Main Heading: Target trackingControlled terms: Adaptive boostingUncontrolled terms: Attention selection - Multiple parts - Object Tracking - online AdaBoost (OAB) - Relaxation factorsClassification Code: 716.2 Radar Systems and Equipment - 723 Computer Software, Data Handling and Applications

Database: Compendex

Image super-resolution via low-rank representation

Li, Zhao1, 2; Wang, Le1; Yu, Tao1, 2; Hu, Bing Liang1 Source: Applied Mechanics and Materials, v 568-570, p 652-655, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.652;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: This paper presents a novel method for solving single-image super-resolution problems, based upon low-rank representation (LRR). Given a set of a low-resolution image patches, LRR seeks the lowest-rank representation among all the candidates that represent all patches as the linear combination of the patches in a low-resolution dictionary. By jointly training two dictionaries for the low-resolution and high-resolution images, we can enforce the similarity of LLRs between the low-resolution and high-resolution image pair with respect to their own dictionaries. Therefore, the LRR of a low-resolution image can be applied with the high-resolution dictionary to generate a high-resolution image. Unlike the well-known sparse representation, which computes the sparsest representation of each image patch individually, LRR aims at finding the lowest-rank representation of a collection of patches jointly. LRR better captures the global structure of image. Experiments show that our method gives good results both visually and quantitatively. © (2014) Trans Tech Publications, Switzerland. (7 refs.)Main Heading: Optical resolving powerControlled terms: Lagrange multipliersUncontrolled terms: Augmented lagrange multipliers - Dictionary trainings - High resolution image - Image super-resolution - Low resolution images - Low-rank representations - Sparse representation - Super resolutionClassification Code: 741.1 Light/Optics - 921 Mathematics

Database: Compendex

Laser induced self-propagating reduction and exfoliation of graphite oxide as an electrode material for supercapacitors

Wang, Dewei1; Min, Yonggang1; Yu, Youhai1; Peng, Bo1 Source: Electrochimica Acta, v 141, p 271-278, September 20, 2014

; ISSN: 00134686; DOI: 10.1016/j.electacta.2014.07.036;

Publisher: Elsevier LtdAuthor affiliation: 1 Institute of Advanced Materials, State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, 710119, China

Abstract: Focused laser beam induced self-propagating reaction has been developed for fabrication of graphene rapidly and efficiently through simultaneous reduction and exfoliation of graphite oxide (GO) process. This chemical-free approach can realize the reduction and exfoliation at room temperature without assistance of any high temperature/vacuum environment. We found that the small sized spot can trigger an ultrafast and highly thermal transferred process by self-propagating reaction at ambient conditions. Benefiting from its high surface area and unique structure, the laser induced self-propagating reaction reduced graphene (LIG) shows excellent capacitive performance. Considering that the cost-effective and feasible process, this facile technique presented here will not only provide a promising method for production of graphene on an industrial scale, but also put forward the application graphene materials in energy storage and conversion. © 2014 Elsevier Ltd. (50 refs.)Main Heading: GrapheneControlled terms: Capacitors - Graphite - Lasers - ReductionUncontrolled terms: Capacitive performance - Electrochemical capacitance - Energy storage and conversions - Focused laser beams - Graphene oxides - Self-propagating reaction - Simultaneous reduction - Super capacitorClassification Code: 704.1 Electric Components - 744.1 Lasers, General - 761 Nanotechnology - 802.2 Chemical Reactions - 804 Chemical Products Generally

Database: Compendex

Error correction of photoelectric rotary and angle encoder

Zhou, Liang1, 2; She, Wen-Ji1; Huang, Jing1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9142, 2014, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410938; DOI: 10.1117/12.2054092; Article number: 91421H; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013, October 20, 2013 - October 29, 2013; Sponsor: Chinese Society of Astronautics; ducation, Shanghai Jiaotong University; Education and Training Department, China; Key Laboratory for Laser Plasmas, Ministry of E; Ordnance Society; Photoelectronic Technology Professional Committee,;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, 710119, Shaanxi Province, China2 University of Chinese Academy of Sciences, Beijing 100864, China

Abstract: The photoelectric rotary and angle encoder is a digital angle measuring device, which is integrated with optics, mechanics and electrics. Because of its simple structure, high resolution, and high accuracy, it has been widely used in precision measurement of angle, digital control and digital display system. With the needs of fast tracking and accurate orientation on the horizon and air targets, putting forward higher requirements on accuracy of angle measurement and resolution of photoelectric rotary and angle encoder. Influences of manufacturing, electronics segmentation, optical and mechanical structure and eccentric shaft to photoelectric encoder precision and reducing methods are introduced. Focusing on the eccentricity error, building up an error correction model to improve the resolution of angle encoder and the model was verified by test. © 2014 Copyright SPIE. (8 refs.)Main Heading: PhotoelectricityControlled terms: Angle measurement - Digital control systems - Display devices - Error compensation - Error correction - Optical image storage - Remote sensingUncontrolled terms: Angle measuring - Digital control - Error correction models - Mechanical structures - Photoelectric encoders - photoelectric rotary and angle encoder - Precision measurement - Simple structuresClassification Code: 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 722.1 Data Storage, Equipment and Techniques - 722.2 Computer Peripheral Equipment - 731.1 Control Systems - 741.1 Light/Optics - 943.2 Mechanical Variables Measurements

Database: Compendex

Toward multiscreen social TV with geolocation-aware social sense

Hu, Han1; Wen, Yonggang2; Luan, Huanbo1; Chua, Tat-Seng1; Li, Xuelong3 Source: IEEE Multimedia, v 21, n 3, p 10-19, July/September 2014

; ISSN: 1070986X; DOI: 10.1109/MMUL.2014.2; Article number: 6730833;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 National University of Singapore, Singapore2 Nanyang Technological University, Singapore3 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, China

Abstract: The increasing popularity of social interactions and geotagged, user-generated content has transformed the television viewing experience from laid-back video watching behavior into a 'lean-forward' socially engaged experience. This article describes a multiscreen, social TV system integrated with social sense via a second screen as a novel paradigm for content consumption. This new application is built upon the authors' cloud-centric media platform, which provides on-demand virtual machines for content platform services, including media distribution, storage, and processing. The media platform is also integrated with a Big Data social platform that crawls and mines social data related to the media content. Specifically, this new social TV approach consists of three key subsystems: interactive TV, social sense, and multiscreen orchestration. Interactive TV implements a cloud-based, social TV system, offering rich social features; social sense discovers the geolocation-aware public perception and knowledge related to the media content; and multiscreen orchestration provides an intuitive and user-friendly human-computer interface to combine the two other subsystems, fusing the TV viewing experience with social perception. The authors have built a proof-of-concept demo over a private cloud at the Nanyang Technological University (NTU), Singapore. Feature verification and performance comparisons demonstrate the feasibility and effectiveness of the proposed approach in transforming the TV viewing experience. © 2014 IEEE. (13 refs.)Main Heading: Interactive televisionControlled terms: Big data - Cloud computing - Digital storage - Digital television - Tracking (position)Uncontrolled terms: Interactive TV - multimedia - Social media analysis - social sense - Social TVClassification Code: 716.2 Radar Systems and Equipment - 716.4 Television Systems and Equipment - 722.1 Data Storage, Equipment and Techniques - 722.4 Digital Computers and Systems

Database: Compendex

Bound-state solitons in a linear-cavity fiber laser mode-locked by single-walled carbon nanotubes

Guo, J.1 Source: Journal of Modern Optics, v 61, n 12, p 980-985, July 12, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.916361;

Abstract: The bound-state solitons generated from a nanotube-mode-locked linear-cavity fiber laser are experimentally observed and numerically simulated for the first time to authors best knowledge. Two chirped fiber Bragg gratings are exploited as the mirrors for the proposed laser. The pulse duration of solitons is about 6.3 ps and the pulse-to-pulse separation is about 23 ps in the experimental observations. Numerical simulations confirm the experimental results and agree well with the experimental observations. Both experimental and numerical results show that the bound-state solitons are strongly stable. © 2014 Taylor and Francis. (62 refs.)Main Heading: SolitonsControlled terms: Excitons - Fiber lasers - Laser mirrors - Locks (fasteners) - Mode-locked fiber lasers - Nanotubes - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Bound state - Chirped fiber Bragg grating - Linear cavity - Mode-locked - Numerical results - Pulse durationsClassification Code: 601.3 Mechanisms - 744 Lasers - 761 Nanotechnology - 931.3 Atomic and Molecular Physics

Database: Compendex

Calibration of stiffness of optical tweezers in three dimensions with power spectral density method

Liang, Yan-Sheng1; Yao, Bao-Li1; Lei, Ming1; Yu, Xiang-Hua1; Yan, Shao-Hui1; Yang, Yan-Long1; Dan, Dan1; Gao, Peng1; Min, Jun-Wei1; Ye, Tong1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 5, May 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144305.0535001; Article number: 0535001;

Abstract: An optical tweezers system which can accurately and quickly calibrate the stiffness of optical tweezers in three dimensions was set up combined with quadrant photodiode detector and power spectral density method. The limited Brownian motion of the trapped particle was recorded by a quadrant photodiode detector, and the stiffness of optical tweezers was calibrated by power spectral density method. The relations of the laser power with the stiffness of a 0.97 μm-diameter silica bead and of the 1 μm-diameter PMMA bead were investigated. The results indicate that the stiffness is proportional to the laser power at the range from 50 mW to 120 mW of laser power for a 0.97 μm-diameter silica bead and at the range from 80 mW to 130 mW for a 1 μm-diameter PMMA bead. This system can be used as a precise force measuring tool for microscopic investigation in biology, physics, etc. (19 refs.)Main Heading: StiffnessControlled terms: Brownian movement - Calibration - Detectors - Optical tweezers - Photodiodes - SilicaUncontrolled terms: Laser power - Measuring tools - Power spectral density method - Quadrant photodiode detectors - Silica beads - Three dimensions - Trapped particleClassification Code: 421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 741.3 Optical Devices and Systems - 744.9 Laser Applications - 812 Ceramics, Refractories and Glass - 914 Safety Engineering - 931 Classical Physics; Quantum Theory; Relativity - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments - 951 Materials Science

Database: Compendex

Observation of vector- and scalar-pulse in a nanotube-mode-locked fiber laser

Yun, Ling1; Liu, Xueming1; Han, Dongdong1 Source: Optics Express, v 22, n 5, p 5442-5447, March 10, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.005442;

Publisher: Optical Society of AmericaAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We report the experimental observations of vector pulse trapping and scalar dissipative soliton in a compact nanotube-mode-locked all-fiber laser for the first time to our best knowledge. The vector pulse exhibits a smooth Gaussian spectral profile without any sidebands. Although two orthogonally polarized components of the vector pulse have different central wavelengths, they copropagate as a unit in the laser cavity with the same speed. The scalar dissipative soliton shows a rectangular spectrum with pulse duration of &sim;13 ps, and can be compressed to &sim;320 fs external to the cavity. This flexible laser provides stable, ultrashort vector- and scalarpulsed sources, which is convenient and attractive for practical applications. © 2014 Optical Society of America. (43 refs.)Main Heading: VectorsControlled terms: Fiber lasers - Locks (fasteners) - Mode-locked fiber lasers - Nanotubes - SolitonsUncontrolled terms: All-fiber lasers - Central wavelength - Dissipative solitons - Gaussians - Polarized components - Pulse durations - Pulse trapping - Spectral profileClassification Code: 601.3 Mechanisms - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 921.1 Algebra

Database: Compendex

Effect of energy density on the machining character of C/SiC composites by picosecond laser

Liu, Yongsheng1; Wang, Chunhui1; Li, Weinan2; Yang, Xiaojun2; Zhang, Qing1; Cheng, Laifei1; Zhang, Litong1 Source: Applied Physics A: Materials Science and Processing, v 116, n 3, p 1221-1228, September 2014, Plasmonics and Metamaterials

; ISSN: 09478396, E-ISSN: 14320630; DOI: 10.1007/s00339-013-8213-2;

Publisher: Springer VerlagAuthor affiliation: 1 Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an 710072 Shaanxi, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 10068 Shaanxi, China

Abstract: The effect of laser energy density on the machining character of C/SiC composites by picosecond laser was investigated using two machining modes: single ring line and helical lines scanning. For single ring line scanning mode, the width and depth of machining grooves increased nonlinearly with the increase of laser energy density. Moreover, periodic surface structures (ripples) were generated at relative low laser energy density and disappeared at high energy density. With the increasing energy density, the oxygen content of machining debris increased dramatically. For helical lines scanning mode, the depth of machining grooves increased nonlinearly with the increasing laser energy density. With the increasing energy density, the oxygen content of machining debris also increased dramatically. The machining character showed as nano-scale laser-induced ripples, pores, strip structures and bubble pits. Finally, micro-holes of high aspect ratio were obtained in the mode of helical lines scanning by removing multiple layers. © 2013 Springer-Verlag Berlin Heidelberg. (32 refs.)Main Heading: ScanningControlled terms: Aspect ratio - DebrisUncontrolled terms: High aspect ratio - High energy densities - Laser energy density - Laser-induced ripples - Line scanning modes - Low laser energy density - Periodic surface structures - Picosecond laserClassification Code: 452.3 Industrial Wastes - 741.3 Optical Devices and Systems - 943 Mechanical and Miscellaneous Measuring Instruments

Database: Compendex

Three operation regimes with an L-band ultrafast fiber laser passively mode-locked by graphene oxide saturable absorber

Zhao, Junqing1; Wang, Yonggang2; Ruan, Shuangchen1; Yan, Peiguang1; Zhang, Han3; Tsang, Yuen H.4; Yang, Jinhui1; Huang, Guoxi1 Source: Journal of the Optical Society of America B: Optical Physics, v 31, n 4, p 716-722, April 1, 2014

; ISSN: 07403224; DOI: 10.1364/JOSAB.31.000716;

Publisher: Optical Society of AmericaAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, Technology of Guangdong Higher Education Institutes, Shenzhen University, Shenzhen, Guangdong 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 College of Optoelectronic Engineering, Shenzhen University, ShenZhen 518060, China4 Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, Hong Kong

Abstract: We present three operation regimes with an L-band erbium-doped fiber laser passively mode-locked by a graphene oxide saturable absorber (GOSA) that is fabricated by using a wet chemical method. One is a stable state of single soliton emission with pulse duration of 426 fs, which is the shortest pulse duration ever achieved with an L-band design by employing GOSA as the mode-locker. The other two operation regimes include bound-state soliton and dual-wavelength nanosecond pulse generation, which are demonstrated for the first time by using the GOSA mode-locker. Our results further indicate the practical potential of GOSA in ultrafast fiber lasers for achieving various mode-locking regimes. © 2014 Optical Society of America. (40 refs.)Main Heading: Locks (fasteners)Controlled terms: Fiber lasers - Graphene - Passive mode locking - Pulse generators - Saturable absorbers - SolitonsUncontrolled terms: Erbium doped fiber laser - Graphene oxides - Nanosecond pulse generation - Operation regime - Passively mode-locked - Pulse durations - Ultrafast fiber lasers - Wet-chemical methodClassification Code: 601.3 Mechanisms - 713.4 Pulse Circuits - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 931.3 Atomic and Molecular Physics

Database: Compendex

Optimization design method of cam curve for zoom lens

Chen, Weining1; Yang, Hongtao1; Liu, Wei1; Fan, Zheyuan1; Zhang, Zhaohui1; Zhou, Zuofeng1; Liu, Guangsen1; Lei, Yangjie1; Zhu, Qing1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 5, p 1535-1539, May 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Zoom cam is a pivotal part used for driving every lens group in zoom lens, the design result of cam curve is decisive importance for motion property and system precision as well as system imaging in zoom system, therefore, zoom cam design is an important part of the zoom lens design, a fine cam performance is the basic requirements to reach lens design of image quality goal and optical zoom process. In order to design a excellent curve form to ensure the pressure angle was smaller, make the process stability and movement smooth fluent, reduce the zoom systems driving moment, and ensure a stability zoom imaging, in the cam design process, we constructed functions which were driving moments of variable group and compensation group with their own pressure angle. Then, combination goal optimization function was built, optimal values of variable group curve pressure angle and compensation group curve pressure angle were optimized and calculated. Optimization results show that the cam drive moment significantly reduces, and improve the overall performance of zoom cam is improved. (9 refs.)Main Heading: Curve fittingControlled terms: Cams - Optical design - Optical instrument lensesUncontrolled terms: Decisive importance - Objective optimization - Optical zoom - Optimal values - Optimization design - Optimization function - Pressure angles - Process stabilityClassification Code: 601.3 Mechanisms - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

Dual-channel dispersionless slow light based on plasmon-induced transparency

Han, Xiaoxiang1 Source: Applied Optics, v 53, n 1, p 9-13, January 1, 2014

; ISSN: 1559128X, E-ISSN: 15394522; DOI: 10.1364/AO.53.000009;

Abstract: I have proposed a dual-channel dispersionless slow-light waveguide system based on plasmon-induced transparency. By appropriately tuning the stub depth, two transparency windows in the transmission spectrumcan be achieved due to the destructive interference between the electromagnetic fields from the three stubs. Two flat bands can be achieved in the transparency windows, which have nearly constant group indices over the bandwidth of 2 THz. The analytical results show that the group velocity dispersion parameters of the two channels equal zero, which indicates that the incident pulse can be slowed down without distortion. The proposed plasmonic waveguide system can realize slow-light effect without pulse distortion, and thus can find important applications on slow-light systems, optical buffers, and all-optical signal processors in highly integrated optical circuits. © 2014 Optical Society of America. (43 refs.)Main Heading: TransparencyControlled terms: Electromagnetic fields - Group velocity dispersion - Optical waveguides - Plasmons - Signal processing - WaveguidesUncontrolled terms: Analytical results - Destructive interference - Group velocities - Integrated optical circuit - Plasmonic waveguides - Pulse distortion - Signal processor - Waveguide systemsClassification Code: 701 Electricity and Magnetism - 711 Electromagnetic Waves - 712.1 Semiconducting Materials - 714.3 Waveguides - 716.1 Information Theory and Signal Processing - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 751 Acoustics, Noise. Sound

Database: Compendex

Optical properties of SrAl<inf>2</inf>O<inf>4</inf>: Eu2+ phosphor in glass

He, Quanlong1, 2; Hu, Changchuan3 Source: Optical Materials, v 38, p 286-289, December 1, 2014

; ISSN: 09253467; DOI: 10.1016/j.optmat.2014.10.055;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 College of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, China

Abstract: Phosphor-in-glass (PiG) typed robust color converters were fabricated using pb-free silicate glasses for luminescence materials applications. The PiG based on a SiO<inf>2</inf>-B<inf>2</inf>O<inf>3</inf>-BaCO<inf>3</inf> ternary system and SrAl<inf>2</inf>O<inf>4</inf>: Eu2+ phosphor showed good transparency reached 99.50%, even if the GTP ratio is 25:1. By simply changing the mixing ratio of glass to SrAl<inf>2</inf>O<inf>4</inf>: Eu2+ phosphor, the emission color of PiG can be controlled from blue to bluish green. The results reveal that the luminescence properties of SrAl<inf>2</inf>O<inf>4</inf>: Eu2+ distinct from the phosphor in glass significantly. These suggest that PiG could provide potential application in a variety of luminescence materials. (18 refs.)Main Heading: PhosphorsControlled terms: Europium - Glass - Luminescence - Mammals - Optical properties - Silicates - Torque convertersUncontrolled terms: Bluish green - Emission color - Luminescence material - Luminescence properties - Mixing ratios - Pb-free - Silicate glassClassification Code: 414 Masonry Materials - 547.2 Rare Earth Metals - 662.4 Automobile and Smaller Vehicle Components - 741.1 Light/Optics - 812 Ceramics, Refractories and Glass - 812.3 Glass - 821 Agricultural Equipment and Methods; Vegetation and Pest Control

Database: Compendex

Multiresolution imaging

Lu, Xiaoqiang1; Li, Xuelong1 Source: IEEE Transactions on Cybernetics, v 44, n 1, p 149-160, January 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2286496; Article number: 6671369;

Abstract: Imaging resolution has been standing as a core parameter in various applications of vision. Mostly, high resolutions are desirable or essential for many applications, e.g., in most remote sensing systems, and therefore much has been done to achieve a higher resolution of an image based on one or a series of images of relatively lower resolutions. On the other hand, lower resolutions are also preferred in some cases, e.g., for displaying images in a very small screen or interface. Accordingly, algorithms for image upsampling or downsampling have also been proposed. In the above algorithms, the downsampled or upsampled (super-resolution) versions of the original image are often taken as test images to evaluate the performance of the algorithms. However, there is one important question left unanswered: whether the downsampled or upsampled versions of the original image can represent the low-resolution or high-resolution real images from a camera? To tackle this point, the following works are carried out: 1) a multiresolution camera is designed to simultaneously capture images in three different resolutions; 2) at a given resolution (i.e., image size), the relationship between a pair of images is studied, one gained via either downsampling or super-resolution, and the other is directly captured at this given resolution by an imaging device; and 3) the performance of the algorithms of super-resolution and image downsampling is evaluated by using the given image pairs. The key reason why we can effectively tackle the aforementioned issues is that the designed multiresolution imaging camera can provide us with real images of different resolutions, which builds a solid foundation for evaluating various algorithms and analyzing the images with different resolutions, which is very important for vision. © 2013 IEEE. (5 refs.)Main Heading: AlgorithmsControlled terms: Cameras - Optical resolving power - Signal processing - Signal samplingUncontrolled terms: Different resolutions - Downsampling - Image down samplings - Imaging resolutions - Multiresolution - optimal imagery - Remote sensing system - Super resolutionClassification Code: 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741.1 Light/Optics - 742.2 Photographic Equipment - 921 Mathematics - 922 Statistical Methods

Database: Compendex

Improvement of image deblurring for opto-electronic joint transform correlator under projective motion vector estimation

Xiao, Xiao1; Zhao, Hui2; Zhang, Yang1 Source: Optics Communications, v 321, p 189-194, June 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.02.006;

Publisher: ElsevierAuthor affiliation: 1 School of Telecommunication Engineering, Xidian University, Xi'an 710071, China2 Xi'An Institute of Optics and Precision Mechanics, CAS, Xi'an 710119, China

Abstract: In this paper we propose an efficient algorithm to improve the performance of image deblurring based on opto-electronic joint transform correlator (JTC) that is capable of detecting the motion vector of a space camera. Firstly, the motion vector obtained from JTC is divided into many sub-motion vectors according to the projective motion path, which represents the degraded image as an integration of the clear scene under a sequence of planar projective transforms. Secondly, these sub-motion vectors are incorporated into the projective motion Richardson-Lucy (RL) algorithm to improve deblurred results. The simulation results demonstrate the effectiveness of the algorithm and the influence of noise on the algorithm performance is also statically analyzed. © 2014 Elsevier B.V. (13 refs.)Main Heading: Image compressionControlled terms: Algorithms - Image enhancement - Image reconstruction - Light modulators - Signal processingUncontrolled terms: Algorithm performance - Fourier optics and signal processing - Image deblurring - Image reconstruction-restoration - Joint transform correlators - Motion vector estimation - Projective transforms - Spatial light modulatorsClassification Code: 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921 Mathematics

Database: Compendex

Nanotube-mode-locked fiber laser delivering dispersion-managed or dissipative solitons

Han, Xiaoxiang1 Source: Journal of Lightwave Technology, v 32, n 8, p 1472-1476, April 15, 2014

; ISSN: 07338724; DOI: 10.1109/JLT.2014.2306961; Article number: 6744596;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We have proposed a bidirectional erbium-doped fiber laser delivering dispersion-managed soliton (DMS) or dissipative soliton (DS) based on a single-wall carbon nanotube mode-locker. In the proposed scheme, the net cavity dispersion approaches to zero in the counter-clockwise (CCW) direction while is normal in the clockwise (CW) direction. By properly adjusting the intracavity attenuators, DMS in the CCW direction and DS in the CW direction can be obtained, respectively. However, attributing to the cavity asymmetry between CCW and CW directions, simultaneous generation of DMS and DS is not achieved. Although the output DMS and DS almost have the same central wavelength, they exhibit distinct optical spectra, pulse durations, and repetition rates. The switchable all-fiber laser delivers two different types of ultra-short pulses, which significantly facilitates the practical applications. © 1983-2012 IEEE. (54 refs.)Main Heading: Dispersion (waves)Controlled terms: Clocks - Dispersions - Fiber lasers - Locks (fasteners) - Nanotubes - Pulse repetition rate - SolitonsUncontrolled terms: All-fiber lasers - Central wavelength - Counter-clockwise - Dispersion managed solitons - Dissipative solitons - Erbium doped fiber laser - Optical spectra - SwitchableClassification Code: 943.3 Special Purpose Instruments - 931.3 Atomic and Molecular Physics - 761 Nanotechnology - 951 Materials Science - 744.4 Solid State Lasers - 711.1 Electromagnetic Waves in Different Media - 601.3 Mechanisms - 744.1 Lasers, General

Database: Compendex

Talbot effect and noise reduction in image processing based on Gyrator transform

Ma, Yuanhua1, 2; Hu, Bingliang1; Li, Ran1; Sun, Lang1, 2; Sun, Nian1, 2; Wang, Zhengjie1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 2, p 665-670, February 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Laboratory of Spectral Imaging Technique, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Based on the principle of Gyrator transform, the self -imaging effect, i.e., the Talbot effect, was investigated firstly. The condition under which the Gyrator transform Talbot effect can occur was given, and the difference between the Talbot effect mentioned in this paper and the traditional Talbot effect was found the Talbot angle was not fixed, the distribution of the angles was not linear, and the fractional Gyrator transform Talbot effect could not obtain through fractionalizing the Talbot angle. Secondly, noise reduction in image processing based on Gyrator transform was also discussed in the paper. It was found that the Gyrator transform could not only reduce the hyperbolic noise efficiently, but also can reduce the-kind noise that brings hyperbolic information efficiently. At last, the shortcoming of the study and follow-up investigations were pointed out. The research in this paper can help people understand Gyrator transform deeply, also develop the self-imaging and noise reduction techniques. (9 refs.)Main Heading: Noise abatementControlled terms: Diffraction gratings - Gyrators - Image processing - Mathematical transformationsUncontrolled terms: Gyrator transform - Imaging effects - Noise reduction technique - Self imaging - Talbot effectsClassification Code: 708.4 Magnetic Materials - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 751.4 Acoustic Noise - 921.3 Mathematical Transformations

Database: Compendex

A novel compact large relative aperture visible optical system

Wang, Hu1, 2; Luo, Jianjun1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 851-855, March 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Based on the special chromatic aberration and thermal aberration of diffractive optical element, which are used in optical system of visible camera for space debris, a novel compact and good image quality large relative aperture space debris camera optical system was designed. The novel system solved the problem that the conventional system had small relative aperture and complex structure. The novel system had an effective focal length of 100 mm, a relative aperture of F/1.5, a field of view of 6°. The system met the requirements of visible space debris camera in encirc energy, the dispersion spot diameter, lateral color, distortion, athermalization and so on. This novel system had light weight, compact structure and good image quality by using diffractive optical element, which provided a new idea for designing visible space debris camera optical system. (10 refs.)Main Heading: Optical systemsControlled terms: Aberrations - Cameras - Density (optical) - Diffractive optical elements - Diffractive optics - Image qualityUncontrolled terms: Aspheric surfaces - Athermalization - Chromatic aberration - Compact structures - Complex structure - Conventional systems - Effective focal lengths - Visible camerasClassification Code: 741 Light, Optics and Optical Devices - 742.2 Photographic Equipment

Database: Compendex

Mid-infrared Raman amplification and wavelength conversion in dispersion engineered silicon-on-sapphire waveguides

Wang, Zhaolu1; Liu, Hongjun1; Huang, Nan1; Sun, Qibing1; Li, Xuefeng2 Source: Journal of Optics (United Kingdom), v 16, n 1, January 2014

; ISSN: 20408978, E-ISSN: 20408986; DOI: 10.1088/2040-8978/16/1/015206; Article number: 015206;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an 710119, China2 School of Science, Xi'An University of Post and Telecommunications, Xi'an 710121, China

Abstract: Raman amplification based on stimulated Stokes Raman scattering (SSRS) and wavelength conversion based on coherent anti-Stokes Raman scattering (CARS) are theoretically investigated in silicon-on-sapphire (SOS) waveguides in the mid-infrared (IR) region. When the linear phase mismatch Δk is close to zero, the Stokes gain and conversion efficiency drop down quickly due to the effect of parametric gain suppression when the Stokes-pump input ratio is sufficiently large. The Stokes gain increases with the increase of Δk, whereas efficient wavelength conversion needs appropriate Δk under different pump intensities. The conversion efficiency at exact linear phase matching (Δk = 0) is smaller than that at optimal linear phase mismatch by a factor of about 28 dB when the pump intensity is 2 GW cm-2. © 2014 IOP Publishing Ltd. (35 refs.)Main Heading: Raman scatteringControlled terms: Amplification - Coherent scattering - Conversion efficiency - Dispersions - Infrared devices - Optical frequency conversion - Pumps - Raman spectroscopyUncontrolled terms: Coherent anti-Stokes Raman scattering - Linear phase - Midinfrared - Parametric gain - Pump intensities - Raman amplification - Silicon-on-sapphireClassification Code: 525.5 Energy Conversion Issues - 618.2 Pumps - 711 Electromagnetic Waves - 741 Light, Optics and Optical Devices - 951 Materials Science

Database: Compendex

Sparse frontal face image synthesis from an arbitrary profile image

Zhao, Lin1; Gao, Xinbo1; Yuan, Yuan2; Tao, Dapeng3 Source: Neurocomputing, v 128, p 466-475, March 27, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.08.018;

Publisher: ElsevierAuthor affiliation: 1 School of Electronic Engineering, Xidian University, Xi'an 710071, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 School of Electronic and Information Engineering, South China University of Technology, GuangZhou 510640, China

Abstract: Frontal face image synthesis from an arbitrary profile image plays an important role in automatic video surveillance systems, and remains a challenge in computer vision. The strategies of partition are popular and promising for synthesizing frontal face images. However, conventional rectangular partition criterions fail to align corresponding patches in profile images and frontal face images. Given an arbitrary profile image, to synthesize a corresponding frontal face image which is smooth in texture and similar in appearance, we introduce a triangulation-based partition criterion and do synthesis based on sparse representation. The triangulation-based partition ensures the corresponding triangular patches are strictly aligned. And sparse representation adaptively finds the most similar patches for synthesis while abandons unlike patches. Furthermore, a confederate learning strategy is proposed to reduce the blocking artifacts caused by triangulation-based partition. Experimental results conducted on the Oriental Face database demonstrate the effectiveness of the proposed frontal face image synthesis method and advantages over previous works. © 2013 Elsevier B.V. (37 refs.)Main Heading: Face recognitionControlled terms: Inverse problems - Security systems - TriangulationUncontrolled terms: Automatic video surveillance systems - Blocking artifacts - Face synthesis - Local patch - Rectangular partition - Sparse representation - Triangulation-based - Virtual frontal viewClassification Code: 405.3 Surveying - 716 Telecommunication; Radar, Radio and Television - 914.1 Accidents and Accident Prevention - 921 Mathematics

Database: Compendex

Optimized graph-based segmentation for ultrasound images

Huang, Qinghua1; Bai, Xiao2; Li, Yingguang1; Jin, Lianwen1; Li, Xuelong3 Source: Neurocomputing, v 129, p 216-224, April 10, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.09.038;

Publisher: ElsevierAuthor affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641 Guangdong, China2 School of Computer Science and Engineering, Beihang University, Beijing 100191, China3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Segmentation of medical images is an inevitable image processing step for computer-aided diagnosis. Due to complex acoustic inferences and artifacts, accurate extraction of breast lesions in ultrasound images remains a challenge. Although there have been many segmentation techniques proposed, the performance often varies with different image data, leading to poor adaptability in real applications. Intelligent computing techniques for adaptively learning the boundaries of image objects are preferred. This paper focuses on optimization of a previously documented method called robust graph-based (RGB) segmentation algorithm to extract breast tumors in ultrasound images more adaptively and accurately. A novel technique named as parameter-automatically optimized robust graph-based (PAORGB) image segmentation method is accordingly proposed and performed on breast ultrasound images. A particle swarm optimization algorithm is incorporated with the RGB method to achieve optimal or approximately optimal parameters. Experimental results have shown that the proposed technique can more accurately segment lesions from ultrasound images compared to the RGB and two conventional region-based methods. © 2013 Elsevier B.V. (26 refs.)Main Heading: Image segmentationControlled terms: Algorithms - Computer aided diagnosis - Graph theory - Graphic methods - Intelligent computing - Medical imaging - Particle swarm optimization (PSO) - Ultrasonic applications - UltrasonicsUncontrolled terms: Breast ultrasound images - Evolutionary Learning - Graph-based segmentation - Segmentation algorithms - Segmentation methods - Segmentation of medical images - Segmentation techniques - Ultrasound image segmentationClassification Code: 921 Mathematics - 753.3 Ultrasonic Applications - 753.1 Ultrasonic Waves - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory - 746 Imaging Techniques - 741 Light, Optics and Optical Devices - 723 Computer Software, Data Handling and Applications - 741.1 Light/Optics

Database: Compendex

Magneto-optical modulation method for measuring glass internal stress

Li, Chun-Yan1, 2; Wu, Yi-Ming1; Gao, Li-Min1; Lu, Wei-Guo1, 2; Xiao, Mao-Sen1 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 1, p 58-62, January 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142201.0058;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: A measuring method for the internal stress magnitude and direction of glass was proposed based on the magneto-optical modulation and a stress measuring system was established. On the basis of the ray-tracing method, the system's measurement model was derived according to the Jones matrix describing manner of polarized light. Then, using a magneto-optical modulator, the signal beam was modulated with a sine alternation manner and the direct measurement of the light intensity signal in the traditional method was changed into the frequency signal measurement to improve the measurement veracity greatly. Furthermore, the human operator error was eliminated through a magneto-optical rotator, and the current for driving a coil outside the rotator was controlled to change the rotation angle of modulation signal light in the polarization direction. Finally, a number of rotating measurements to the sample were carried out. The experimental results indicate that the measurement veracities for stress direction, and the stress birefringence are 5" and 0.3 nm/cm, respectively. In conclusions, the system has the characteristics of high stability, high veracity and easy to be implemented in engineering applications. (9 refs.)Main Heading: Stress measurementControlled terms: Glass - Light modulation - Light modulators - Light polarization - Ray tracing - Residual stressesUncontrolled terms: Engineering applications - Human operator error - Light intensity signals - Magnetic rotation - Magneto-optical - Magneto-optical modulators - Polarization direction - Stress birefringenceClassification Code: 421 Strength of Building Materials; Mechanical Properties - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 812.3 Glass

Database: Compendex

Analysis of extinction ratio of a Glan-Taylor prism

Li, Chunyan1, 2; Wu, Yiming1; Gao, Limin1; Lu, Weiguo1, 2; Wang, Weifeng1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 173-177, January 2014; Language: Chinese

; ISSN: 10072276;

Abstract: The calculation formula of Glan-Taylor prism's transmittance between emanative lights' azimuth, incident angle and structure angle of prism was obtained by using refraction law and Fresnel formula as well as the ray-tracing method. The relationship between the extinction ratio and transmittance was indicated. By computer simulation of Matlab, the characteristic of extinction ratio in the whole azimuth was analyzed; the extinction ratio's transformation relationship along with incident angle and structure angle was investigated. From simulation results, we discover that the extinction ratio is unacted on the incident angle when the angle is in the vertical azimuth of prism's optical axis. And the ratio becomes bad with increasing of the structure angle. The theoretical results are in good agreement with problems appeared from practical system which verifies its correctness, and it explains the problem in project item. The work of this article has great guiding significance in the design and use of Glan-Taylor prism. (9 refs.)Main Heading: Light extinctionControlled terms: Computer simulation - MATLAB - Prisms - Ray tracingUncontrolled terms: Azimuth angles - Calculation formula - Extinction ratios - Guiding significances - Practical systems - Ray-tracing method - Simulation of matlabs - TransmittanceClassification Code: 723.5 Computer Applications - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Spatial and temporal laser pulse design for material processing on ultrafast scales

Stoian, R.1; Colombier, J.P.1; Mauclair, C.1; Cheng, G.1, 2; Bhuyan, M.K.1; Velpula, P.K.1; Srisungsitthisunti, P.1, 3 Source: Applied Physics A: Materials Science and Processing, v 114, n 1, p 119-127, January 2014

; ISSN: 09478396, E-ISSN: 14320630; DOI: 10.1007/s00339-013-8081-9;

Publisher: Springer VerlagAuthor affiliation: 1 Laboratoire Hubert Curien, UMR 5516 CNRS, Université de Lyon, 42000 Saint Etienne, France2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, CAS, Shaanxi, Xi'an 710119, China3 Department of Production Engineering, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand

Abstract: The spatio-temporal design of ultrafast laser excitation can have a determinant influence on the physical and engineering aspects of laser-matter interactions, with the potential of upgrading laser processing effects. Energy relaxation channels can be synergetically stimulated as the energy delivery rate is synchronized with the material response on ps timescales. Experimental and theoretical loops based on the temporal design of laser irradiation and rapid monitoring of irradiation effects are, therefore, able to predict and determine ideal optimal laser pulse forms for specific ablation objectives. We illustrate this with examples on manipulating the thermodynamic relaxation pathways impacting the ablation products and nanostructuring of bulk and surfaces using longer pulse envelopes. Some of the potential control factors will be pointed out. At the same time the spatial character can dramatically influence the development of laser interaction. We discuss spatial beam engineering examples such as parallel and non-diffractive approaches designed for high-throughput, high-accuracy processing events. © 2013 Springer-Verlag Berlin Heidelberg. (60 refs.)Main Heading: Laser ablationControlled terms: Ablation - Design - Laser pulsesUncontrolled terms: Ablation products - Energy relaxation - Engineering aspects - Irradiation effect - Laser pulse designs - Laser-matter interactions - Material processing - Potential controlClassification Code: 408 Structural Design - 641.2 Heat Transfer - 744.1 Lasers, General

Database: Compendex

Design of three-field middle-wave infrared zoom system

Fan, Zheyuan1, 2; Gao, Limin1; Zhang, Zhi1; Chen, Weining1; Yang, Hongtao1, 2; Zhang, Jian1; Wu, Li1; Cao, Jianzhong1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 2, p 523-527, February 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Science, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Three-field zoom system has advantages of simple mechanical structure, better reliability, short time of changing focal relative to other pattern zoom systems. Using 320×240 resolution cooled detector with 30 μm×30 μm pixel dimension, a middle-wave three-field optical system was designed by secondary imaging way. The system's F number is 4, FOV range is 1.4°-23.8°, it can realize 30 mm/100 mm/500 mm three position focal length. In designing process, the Germanium material and Silicon material were adopted to balance chromatic aberration, introducing one asphere to balance sphere aberration. The system use two mirrors reducing the axis dimension. The dimension of system better than 210 mm×160 mm×120 mm, it has characteristics of small dimension, simple zoom structure, good image quality etc. The modulation transfer function (MTF) is above 0.5 at spatial frequency of 17 lp/mm and energy concentration ratio is greater than 70% within the sensing element of the detector. (8 refs.)Main Heading: Optical designControlled terms: Aberrations - Infrared radiation - Optical systemsUncontrolled terms: Chromatic aberration - Energy concentration - Mechanical structures - MTF - MWIR - Spatial frequency - Three-field - ZoomClassification Code: 741 Light, Optics and Optical Devices

Database: Compendex

Method for improving reconstructed image quality of digital hologram based on SRAD and NSCT

Wu, Yiquan1, 2; Yin, Jun1; Zhu, Li1; Ye, Zhilong1 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 2, February 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.0209024; Article number: 0209024;

Publisher: Science PressAuthor affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu 210016, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an, Shaanxi 710068, China

Abstract: Reconstructed image of digital holography has problems such as serious interference of speckle noise, low contrast and so on. Thus a method based on speckle reducing anisotropic diffusion (SRAD) model and nonsubsampled contourlet transform (NSCT) is proposed for improving reconstructed image quality of digital hologram. SRAD model is adopted to eliminate speckle noise of reconstructed image. After NSCT decomposition, a low-frequency sub-band and several high-frequency sub-bands are produced. Low-frequency sub-band coefficients are adjusted based on a nonlinear gain function and an image segmentation method. In high-frequency sub-bands, edges are enhanced using a NSCT modulus maximum edge detection method. A large number of experimental results show that, compared with nonlinear diffusion denoising methods and NSCT enhancement methods proposed recently, the proposed method can more effectively eliminate speckle noise and improve the contrast of reconstructed image. Furthermore, the edges are smooth and clear. As a result, the accuracy of recognition and measurement in digital holography can be improved. (20 refs.)Main Heading: Image reconstructionControlled terms: Computer generated holography - Edge detection - Holograms - Holography - Image quality - Image segmentation - Mathematical transformations - SpeckleUncontrolled terms: Maximum between-cluster variances - Modulus maxima - Non-sub-sampled contourlet transforms - Nonlinear gains - Speckle reducing anisotropic diffusionClassification Code: 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 743 Holography - 743.1 Holographic Techniques - 746 Imaging Techniques - 921.3 Mathematical Transformations

Database: Compendex

Ego motion guided particle filter for vehicle tracking in airborne videos

Cao, Xianbin1; Gao, Changcheng1; Lan, Jinhe2; Yuan, Yuan3; Yan, Pingkun3 Source: Neurocomputing, v 124, p 168-177, January 26, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.07.014;

Publisher: ElsevierAuthor affiliation: 1 School of Electronic Information, BeiHang University, Beijing 100083, China2 School of Computer Science and Technology, University of Science and Technology of China, Hefei 230026, China3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Tracking in airborne circumstances is receiving more and more attention from researchers, and it has become one of the most important components in video surveillance for its advantage of better mobility, larger surveillance scope and so on. However, airborne vehicle tracking is very challenging due to the factors such as platform motion, scene complexity, etc. In this paper, to address these problems, a new framework based on Kanade-Lucas-Tomasi (KLT) features and particle filter is proposed. KLT features are tracked throughout the video sequence. At the beginning of video tracking, a strategy based on motion consistence with RANSAC is utilized to separate background KLT features. The grouping of background features helps estimate the ego motion of the platform and the estimation is then incorporated into the prediction step in particle filter. Color similarity and Hu moments are used in the measurement model to assign the weights of particles. Our experimental results demonstrated that the proposed method outperformed the other tracking methods. © 2013 Elsevier B.V. (27 refs.)Main Heading: Tracking (position)Controlled terms: Computer vision - Monte Carlo methods - Security systems - Video recordingUncontrolled terms: Airborne video - Ego motion - KLT feature - Particle filter - Visual TrackingClassification Code: 716.2 Radar Systems and Equipment - 716.4 Television Systems and Equipment - 723.5 Computer Applications - 914.1 Accidents and Accident Prevention - 922.2 Mathematical Statistics

Database: Compendex

Intense red fluorescence from Ho/Yb codoped tellurite glasses

He, Jianli1, 2; Zhou, Zhiguang1, 2; Zhan, Huan1, 2; Lin, Aoxiang1 Source: Journal of Non-Crystalline Solids, v 383, p 157-160, January 1, 2014

; ISSN: 00223093; DOI: 10.1016/j.jnoncrysol.2013.04.051;

Abstract: By optimizing the concentration ratio of Ho/Yb and using conventional melting and quenching methods, a group of Ho/Yb co-doped tellurite glasses with host composition of 78TeO<inf>2</inf>-12ZnO-10Na<inf>2</inf>O (mol.%, TZN) were made for red fiber laser development. Excited by 976 nm laser diode, intense green and red emissions were detected easily even by naked eyes. TZN glass codoped with 0.5 wt.% Ho<inf>2</inf>O<inf>3</inf> and 3 wt.% Yb <inf>2</inf>O<inf>3</inf> was found to present the strongest red emission with the intensity about three times higher than that of the green one, presenting a yellowish-orange color as observed. Besides direct energy transfer process from Yb to Ho as usual, it is believed that cooperative energy transfer upconversion from a pair of Yb donor ions to one Ho acceptor ion and excited state absorptions among different levels of Ho ion are commonly responsible for the observed intense red emission. © 2012 Elsevier B.V. All rights reserved. © 2013 Elsevier B.V. All rights reserved. (25 refs.)Main Heading: GlassControlled terms: Energy transfer - Fiber lasers - Ions - Optical glass - Tellurium compounds - YtterbiumUncontrolled terms: Concentration ratio - Cooperative energy transfers - Direct energy transfers - Excited state absorption - Fiber materials - Tellurite glass - Up-conversion - Visible lasersClassification Code: 547.2 Rare Earth Metals - 641.2 Heat Transfer - 741.1.2 Fiber Optics - 801 Chemistry - 804.1 Organic Compounds - 812.3 Glass

Database: Compendex

Improved design of microstrip-to-slotline transition

Zhao, Yuan1, 2, 3; Hu, Bing Liang1; Deng, Chao3; Wang, Hong Wei3; Li, Lei4; Wang, Ying4 Source: Applied Mechanics and Materials, v 668-669, p 844-847, 2014

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038353126; DOI: 10.4028/www.scientific.net/AMM.668-669.844; Conference: 3rd Asian Pacific Conference on Mechanical Components and Control Engineering, ICMCCE 2014, September 20, 2014 - September 21, 2014; Sponsor: Nankai University;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian institute of optics and precision mechanics of CAS, Xian; Shaanxi, China2 University of Chinese Academy of Sciences, Beijing, China3 The Engineering University of CAPF, Xian, China4 North Optoelectronic Stock Ltd, Xian; Shaanxi, China

Abstract: A novel compact Ultra-Wide Band (UWB) microstrip-slotline transition utilizing high impedance chip resistor is proposed and analyzed. The reactance introduced by the microstrip open end and slotline short end, which is the main limitation to the bandwidth in the traditional structures, is minimized in the design. The model is analyzed with the method of equivalent circuits and simulated by the commercial software HFSS. To test the performance of this transition a back-to-back structure is fabricated. The measurement results show that the bandwidth of 45 octaves can be obtained while the insert loss S<inf>12</inf> is better than 0.7dB within the band. © (2014) Trans Tech Publications, Switzerland. (9 refs.)Main Heading: Ultra-wideband (UWB)Controlled terms: Bandwidth - Broadband networks - Equivalent circuits - ResistorsUncontrolled terms: Commercial software - Improved designs - Insert loss - Microstrip-to-slotline transitions - Slot-line transition - Traditional structures - Transition - UWBClassification Code: 703.1 Electric Networks - 704 Electric Components and Equipment - 706 Electric Transmission and Distribution - 714 Electronic Components and Tubes - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications

Database: Compendex

Study on an ultrathin terahertz multiband metamaterial absorber

Chen, Xu1; Fan, Wenhui2 Source: International Symposium on Ultrafast Phenomena and Terahertz Waves, ISUPTW 2014, October 13, 2014; Conference: International Symposium on Ultrafast Phenomena and Terahertz Waves, ISUPTW 2014, October 13, 2014 - October 14, 2014; Sponsor: University of Shanghai;

Publisher: Optical Society of America (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China (7 refs.)

Database: Compendex

Adaptive road detection towards multiscale-multilevel probabilistic analysis

Jiang, Zhiyu1, 3; Wang, Qi2; Yuan, Yuan1 Source: 2014 IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014 - Proceedings, p 698-702, September 3, 2014; ISBN-13: 9781479954032; DOI: 10.1109/ChinaSIP.2014.6889334; Article number: 6889334; Conference: 2nd IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014, July 9, 2014 - July 13, 2014; Sponsor: et al.; KC Wong Education Foundation; National Natural Science Foundation of China; Northwestern Polytechnical University; Texas Instruments; The Institute of Electrical and Electronics Engineers (IEEE) Signal Processing Society (SPS);

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, Shaanxi, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Northwestern Polytechnical University, Xi'an, Shaanxi, China3 Graduate University of the Chinese Academy of Sciences, 19A Yuquanlu, Beijing, China

Abstract: Vision-based road detection is a challenging problem because of the changeable shape and varying illumination. Though many efforts have been spent on this topic, the achieved performance is far from satisfactory. To this end, this paper formulates a Bayesian method which simultaneously explores the multiscale-multilevel clues that are considered to be complementary. Two contributions are claimed in this proposed method. 1) By computing the prior distribution in superpixellevel with a novel Laplacian Sparse Subspace Clustering and observation likelihood in pixel-level with statistical color similarity, the posterior probability of road region can be effectively inferred. 2) To ensure the adaptivity of road model in various conditions, a multiscale strategy is presented to fuse the detection results of different scales. Experimental results on several challenging video sequences verify the superiority of the proposed method compared with several popular ones. © 2014 IEEE. (18 refs.)Main Heading: Roads and streetsControlled terms: Bayesian networks - Clustering algorithms - Computer vision - Probability distributions - TransportationUncontrolled terms: Bayesian - clustering - Road detection - sparse - Super pixelsClassification Code: 406.2 Roads and Streets - 431 Air Transportation - 432 Highway Transportation - 433 Railroad Transportation - 434 Waterway Transportation - 721 Computer Circuits and Logic Elements - 723.5 Computer Applications - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory - 922.1 Probability Theory

Database: Compendex

An improved opto-digital joint transform correlator reducing the influence of defocus on image motion measurement

Zhao, Hui1; Yi, Hongwei1; Wei, Jingxuan2; Xie, Xiaopeng3 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9273, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413465; DOI: 10.1117/12.2064959; Article number: 92731C; Conference: Optoelectronic Imaging and Multimedia Technology III, October 9, 2014 - October 11, 2014; Sponsor: Chinese Optical Society (COS); The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, No. 17 Xinxi Road, Xi'an, China2 School of Computer Science and Technology, Xidian University, No.2, South Taibai Road, Xi'an, China3 School of Physical Science and Technology, Inner Mongolia University, No.235 West College Road, Hohhot Inner-Mongolia, China

Abstract: Joint transform correlator (JTC) is a highly efficient way to measure image motion and a hybrid opto-digital JTC (HODJTC) has been proposed by us in [CHIN. OPT. LETT., Vol. 8, No. 8]. Being different from the traditional JTC, only one optical Fourier transform is needed and the optically generated joint power spectrum (JPS) is used to compute the image motion in a digital way. Although a high measurement precision can be obtained through HODJTC, the defocus will counteract the final result. In this paper, the influence of defocus is analyzed and an improved HODJTC, whose sensitiveness to defocus is reduced, is proposed. By introducing randomly generated defocus, a series of cross-correlation peak images is obtained and a subsequent spatial averaging procedure is applied to these images to generate the final cross-peak image which is used to compute the defocus invariant motion value. © 2014 SPIE. (7 refs.)Main Heading: Light modulatorsControlled terms: Multimedia systemsUncontrolled terms: Defocus - Image motion - Joint transform correlators - Motion measurements - Spatial light modulatorsClassification Code: 723.5 Computer Applications - 741.3 Optical Devices and Systems

Database: Compendex

Seal designing of theodolite used in seaside environment

Jin, Humin1; Yan, Xiaoxu1; Hao, Wei1; Zhou, Sizhong1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9285, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413601; DOI: 10.1117/12.2068710; Article number: 928504; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials for Manufacturing and Testing, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: Based on the environment requirements in seaside there exists static and dynamic seal designing for the photoelectric Theodolite. Static seal designing emphatically includes the designing of o-ring size and mechanical property analysis of o-ring seal, which is difficult to adopt conventional dynamic seal to meet the requirements. According to practical application, the combination of the radial labyrinth seal and high quality felt seal are designed. The combination seal which better solves the seal problem of narrow radial size is a good way of dynamic seal. At the same time, there is engineering practice needing to proof the radial labyrinth seal. (6 refs.)Main Heading: SealsControlled terms: Dynamic mechanical analysis - Manufacture - Materials testing - Mechanical properties - O rings - PhotoelectricityUncontrolled terms: Dynamic seals - Engineering practices - High quality - Labyrinth Seal - O-ring seal - Photoelectric theodolite - Seal designingClassification Code: 421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 537.1 Heat Treatment Processes - 619.1.1 Pipe Accessories - 741.1 Light/Optics - 951 Materials Science

Database: Compendex

Compressed sensing based on the improved wavelet transform for image processing

Pang, Peng1, 2; Gao, Wei1; Song, Zongxi1; Xi, Jiang-Bo1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9284, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413595; DOI: 10.1117/12.2069221; Article number: 92840O; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Compressed sensing theory is a new sampling theory that can sample signal in a below sampling rate than the traditional Nyquist sampling theory. Compressed sensing theory that has given a revolutionary solution is a novel sampling and processing theory under the condition that the signal is sparse or compressible. This paper investigates how to improve the theory of CS and its application in imaging system. According to the properties of wavelet transform sub-bands, an improved compressed sensing algorithm based on the single layer wavelet transform was proposed. Based on the feature that the most information was preserved on the low-pass layer after the wavelet transform, the improved compressed sensing algorithm only measured the low-pass wavelet coefficients of the image but preserving the high-pass wavelet coefficients. The signal can be restricted exactly by using the appropriate reconstruction algorithms. The reconstruction algorithm is the key point that most researchers focus on and significant progress has been made. For the reconstruction, in order to improve the orthogonal matching pursuit (OMP) algorithm, increased the iteration layers make sure low-pass wavelet coefficients could be recovered by measurements exactly. Then the image could be reconstructed by using the inverse wavelet transform. Compared the original compressed sensing algorithm, simulation results demonstrated that the proposed algorithm decreased the processed data, signal processed time decreased obviously and the recovered image quality improved to some extent. The PSNR of the proposed algorithm was improved about 2 to 3 dB. Experimental results show that the proposed algorithm exhibits its superiority over other known CS reconstruction algorithms in the literature at the same measurement rates, while with a faster convergence speed. (15 refs.)Main Heading: Wavelet transformsControlled terms: Algorithms - Compressed sensing - Image matching - Image processing - Iterative methods - Manufacture - Materials testing - Optical data processing - Optoelectronic devices - Signal processing - Signal reconstruction - Signal samplingUncontrolled terms: Faster convergence - Inverse wavelet transforms - ITS applications - Nyquist sampling - Orthogonal matching pursuit - Reconstruction algorithms - Sampling theory - Wavelet coefficientsClassification Code: 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 537.1 Heat Treatment Processes - 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921 Mathematics - 922 Statistical Methods - 951 Materials Science

Database: Compendex

Control of ultrafast laser nanostructuring of glasses using temporal and spatial pulse design

Stoian, R.1; Mishchik, K.1; Mauclair, C.1; Velpula, P.K.1; Bhuyan, M.K.1; Colombier, J.P.1; D'Amico, C.1; Zamfirescu, M.2; Cheng, G.3 Source: Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BGPP 2014, July 21, 2014; ISBN-13: 9781557528209; Conference: Bragg Gratings, Photosensitivity, and Poling in Glass Waveguides, BGPP 2014, July 27, 2014 - July 31, 2014;

Publisher: Optical Society of America (OSA)Author affiliation: 1 Laboratoire Hubert Curien, UMR 5516 CNRS, Université de Lyon, Université Jean Monnet, 42000 St. Etienne, France2 National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest, Romania3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, China

Abstract: Laser transformation of optical glasses depends on the rate of energy feedthrough, affecting the resulting function. We discuss the role of spatio-temporal design of laser pulses in 3D nanostructuring either via self-arrangements or direct writing. © 2014 OSA. (7 refs.)Main Heading: GlassControlled terms: Optical glass - Ultrafast lasersUncontrolled terms: Direct writing - Feed through - Laser nano-structuring - Laser transformation - Nano-structuring - Rate-of-energy - Spatio-temporal - Temporal and spatialClassification Code: 744.1 Lasers, General - 812.3 Glass

Database: Compendex

New design method of precise space replicated light-tube

Yin, Xunlong1, 2; Wu, Yiming1; Wu, Cuigang1; Yao, Zhen1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 11, p 3735-3739, November 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: During the calibration and regulation of star simulator inertial measurement unit equipment, the parameter what is the azimuth angle between emergence beam from star simulator and reflected beam of inertial measurement prism is required. The directions of two beams are opposite and there are some space translation in them. The systems require a space replication light-tube for the measurement of the parameter with one theodolite. A new method was proposed for the design of replication light-tube, the light-tube can make the light pace replicate 180 in the horizontal plane and have a two dimensional translation in the plane perpendicular to the optical axis of the star simulator. Right angle roof prism and rhombic prism were used in the design of the light-tube for the purpose to eliminate the installation error of the tube. A double wedges instrument was designed to improve the accuracy of the light-tube. With the use of double wedges, the light pace could title lightly, so the transfer deviation could be eliminated. Experimental results show that the design can not only meet the requirements of the optical path and guarantee delivery accuracy, but also reduce processing costs of the precise replicated light-tube. (6 refs.)Main Heading: Tubes (components)Controlled terms: Design - Error analysis - Parameter estimation - Prisms - Roofs - Simulators - Stars - Units of measurementUncontrolled terms: Azimuth angles - Double wedge - Inertial measurement unit - Inertial measurements - Installation error - Processing costs - Space light replication - Space translationClassification Code: 402 Buildings and Towers - 408 Structural Design - 616.1 Heat Exchange Equipment and Components - 621 Nuclear Reactors - 657.2 Extraterrestrial Physics and Stellar Phenomena - 671 Naval Architecture - 731.1 Control Systems - 741.3 Optical Devices and Systems - 902.2 Codes and Standards - 921.6 Numerical Methods

Database: Compendex

Pylon line spatial correlation assisted transmission line detection

Zhang, Jun1; Shan, Haotian1; Cao, Xianbin1; Yan, Pingkun2; Li, Xuelong2 Source: IEEE Transactions on Aerospace and Electronic Systems, v 50, n 4, p 2890-2905, October 1, 2014

; ISSN: 00189251; DOI: 10.1109/TAES.2014.120732; Article number: 6978886;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronics and Information Engineering, Beihang University, National Key Laboratory of CNS/ATM, Beijing, China2 Center for Optical Imagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: A transmission line is one of the most hazardous objects to low altitude flying aircraft. Due to its extremely tiny size and unsalient visual features, transmission line detection (TLD) is a well-recognized problem. In this paper, a novel TLD method is proposed with the assistance of the spatial correlation between pylon and line for TLD. First, a unidirectional spatial mapping is built up to describe the pylon line spatial correlation. Then, the proposed pylon line spatial correlation and other line features are integrated into a Bayesian framework, which is trained in advance and used to estimate the probability of one line segment belonging to a transmission line. Compared with three other line-based TLD methods, the experimental results demonstrate that the proposed method can obtain better detection performance with higher detection rates and much lower false alarm rates. Poles and towers, Power transmission lines, Correlation, Image segmentation, Feature extraction, Silicon, Bayes methods (36 refs.)Main Heading: Electric linesControlled terms: Correlation methods - Electric power transmission - Extraction - Feature extraction - Image segmentation - Poles - Power transmission - Silicon - Transmission line theoryUncontrolled terms: Bayes method - Bayesian frameworks - Detection performance - Detection rates - False alarm rate - Poles and towers - Spatial correlations - Spatial mappingClassification Code: 408.2 Structural Members and Shapes - 602.2 Mechanical Transmissions - 706.1.1 Electric Power Transmission - 706.2 Electric Power Lines and Equipment - 712.1.1 Single Element Semiconducting Materials - 716 Telecommunication; Radar, Radio and Television - 741.1 Light/Optics - 802.3 Chemical Operations - 922.2 Mathematical Statistics

Database: Compendex

Study on writing of double line waveguide in Yb:YAG with ultrafast laser

Tang, Wenlong1, 2; Song, Qiongge1, 2; Xu, Qing'an3; Liu, Xin1, 2; Cheng, Guanghua1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 12, December 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.1232002; Article number: 1232002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China2 University of Chinese Academy of Sciences, Beijing , China3 Beijing Institute of Control Engineering, Beijing , China

Abstract: The writing of double line waveguide in Yb3+ doped yttrium aluminum garnet (Yb:YAG) crystal is studied by using titanium sapphire laser with the pulse width of 160 fs, central wavelength of 775 nm and repetition frequency of 50 kHz. The phenomenon of polarization guiding is discovered in the waveguide. The laser with polarization parallel to the direction of double line can be guided, but the laser with polarization perpendicular to the direction of double line cannot be guided. The effects of written parameters, such as double line separation, laser pulse energy and writing speed, on the formation of the waveguide are analyzed. Experimental results show that the waveguide has the good property of guiding under the writing conditions of double line separation of 30 μm, writing speed of 400 μm/s and pulse energy of 5.0 μJ. Bivariate distribution of the waveguide refractive index is reconstructed by near-field mode and the maximum refractive index change is 1.8×10-4. A continuous waveguide laser with a wavelength of 1030.5 nm is obtained and the output power is 4.7 mW. (28 refs.)Main Heading: WaveguidesControlled terms: Aluminum - Garnets - Integrated optics - Optical waveguides - Polarization - Refractive index - Sapphire - Ultrafast lasers - Ytterbium - YttriumUncontrolled terms: Bivariate distribution - Continuous waveguides - Laser-pulse energy - Refractive index changes - Repetition frequency - Titanium sapphire laser - Waveguide lasers - Yttrium aluminum garnetClassification Code: 482.2 Minerals - 482.2.1 Gems - 541.1 Aluminum - 547.2 Rare Earth Metals - 549.3 Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals - 714.3 Waveguides - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General

Database: Compendex

Grid-controlled emission source for space X-ray communication

Ma, Xiao-Fei1, 2; Zhao, Bao-Sheng1; Sheng, Li-Zhi1; Liu, Yong-An1; Liu, Duo1, 2; Deng, Ning-Qin3 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 16, August 20, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.160701; Article number: 160701;

Publisher: Institute of Physics, Chinese Academy of SciencesAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China3 School of Information Science and Technology, Tsinghua University, Beijing , China

Abstract: Using X-ray as carrier signal to realize the high rate information transmission in a distant space is attracting the attention of researchers. The development of this technology has a positive significance for broadening the scope of use of the electromagnetic spectrum. In this paper, the novel grid control X-ray source, which consists of a traditional X-ray tube and a signal control grid, is designed to meet the requirements of X-ray communication in the simulation vacuum experimental system by means of three-dimensional electromagnetic simulation software CST particle studio. The tube potential distribution, electron trajectory, actual focal spot and the number of electrons at the anode are simulated by the computer simulation software. It works by changing the grid voltage to control the X-ray pulse emission. The data of the simulation are as follows. The actual focal spot size is 0.4 mm × 4 mm, the effective gate-on voltage is 0 V, and the gate-off voltage is -10 V. X-ray tube grid-controlled characteristics are tested in experiment. The test results are well consistent with the simulation results. Finally, the digital signal transmission is successfully implemented in the X-ray vacuum experiment system. © 2014 Chinese Physical Society (11 refs.)Main Heading: X ray tubesControlled terms: Computer simulation - Computer software - Electron sources - Experiments - Tubes (components) - X ray apparatusUncontrolled terms: Digital signal transmission - Electromagnetic simulation - Electromagnetic spectra - Electron trajectories - Focal spot size - Information transmission - Potential distributions - X-ray sourcesClassification Code: 422.1 Strength of Building Materials : Test Equipment - 616.1 Heat Exchange Equipment and Components - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 801 Chemistry - 901.3 Engineering Research - 932.1 High Energy Physics

Database: Compendex

Harmonic mode locking of dark and dark-bright pluses emission from a graphene-oxide ytterbium-doped fiber laser

Lin, Rongyong1; Wang, Yonggang2; Zhang, Gelin1; Yan, Peiguang1; Zhao, Junqing1; Li, Huiquan1; Huang, Shisheng1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, September 10, 2014

; ISSN: 02532239; DOI: 10.3788/AOS201434.s114014; Article number: s114014;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, College of Electronic Science and Technology, Shenzhen University, Shenzhen; Guangdong , China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: Generation of harmonic mode locking (HML) of dark and dark-bright pulses in an Ytterbium-doped fiber (YDF)laser based on a graphene-oxide (GO) saturable absorber (SA) is investigated experimentally. Both the bunch of dark-bright pulses and high-order HML of bright pulses can be obtained in the cavity. The above operation states are switched by changing the polarization controller (PC) and the pump power. The 56th order harmonic of dark pulses is achieved. The HML of dark-bright pulses can be generated with order up to 6th, and the HML order of bright pulses is up to 1084th. (33 refs.)Main Heading: Mode-locked fiber lasersControlled terms: Fiber lasers - Graphene - Harmonic analysis - Lasers - Locks (fasteners) - Saturable absorbers - YtterbiumUncontrolled terms: Bright pulse - Dark pulse - Generation of harmonics - Harmonic mode locking - Operation state - Polarization controllers - Ytterbium doped fibers - Ytterbium-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 921.6 Numerical Methods

Database: Compendex

Structure modeling, analysis and thermal experiment of the active cooling focal plane of aspace astronomy telescope

Feng, Liang-Jie1; Ren, Guo-Rui1; Yang, Wen-Gang1; Wang, Chen-Jie1 Source: Yuhang Xuebao/Journal of Astronautics, v 35, n 10, p 1218-1222, October 30, 2014; Language: Chinese

; ISSN: 10001328; DOI: 10.3873/j.issn.1000-1328.2014.10.016;

Publisher: China Spaceflight SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: The CCD focal plane of the visible telescope on an astronomy satellite is analysed. The actively cooling structure of the focal plane is designed to satisfy -65 working temperature. The maximum stress of the TEC and the thermal conductive adhesive under the working temperature is fully calculated by the finite element method, the results show that the maximum stress of the TEC is 14 MPa and the maximum shear stress of the thermal conductive structure adhesive is 1.2 MPa, which is well below the allowable safety stress. The developed focal plane simulator has passed the thermal vaccum test, and also has validated the cooling ability and the safety of the focal plane assembly. (6 refs.)Main Heading: Finite element methodControlled terms: Astronomy - Cooling - Focusing - Shear stress - Telescopes - Thermal stressUncontrolled terms: Active cooling - Astronomy satellite - Conductive adhesive - Focal plane assemblies - Maximum shear stress - Thermal electric cooling (TEC) - Thermal vaccum - Working temperaturesClassification Code: 421 Strength of Building Materials; Mechanical Properties - 641.2 Heat Transfer - 657 Space Physics - 657.2 Extraterrestrial Physics and Stellar Phenomena - 711.1 Electromagnetic Waves in Different Media - 921.6 Numerical Methods

Database: Compendex

Aerial vehicle astronomy autonomous navigation technology

Liang, Dongsheng1, 2; Liu, Zhaohui1; Liu, Wen1; Yuan, Hui1, 2; Liu, Fucheng1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 9, p 3020-3025, September 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: In allusion to the deficiencies of traditional inertial celestial integrated algorithm and selection uncertainty of the NAVSTAR, an algorithm based on SINS/CNS deeply integrated navigation with single star was proposed in this paper for the navigation system of long duration aero crafts. The error characteristics of inertial navigation and the star observation of two-gimbal were modeled exactly, and the advantages of both were analyzed and synthesized, the data of single star observation angle and inertial navigation was fused with high accuracy completely. In the height channel, barometric altimeter was introduced for altitude error damping. The design of the Kalman filter achieved optimal estimation of INS error. With analysis of the system observability, optimal NAVSTAR selection criteria was successfully brought out, effective solution to the problem of declining performance of the algorithm in the part of the observation angle was solved effectively. The simulation results of the algorithm show that the long positioning accuracy is better than traditional algorithm. Optimal NAVSTAR selection criteria effectively improve the robustness of the algorithm, which has a higher significance to theoretical study and engineering application value. (15 refs.)Main Heading: AlgorithmsControlled terms: Air navigation - Inertial navigation systems - Navigation - Observability - StarsUncontrolled terms: Autonomous navigation - CNS - Engineering applications - Error characteristics - Integrated algorithm - Integrated navigation - Navstar - SINSClassification Code: 431.5 Air Navigation and Traffic Control - 657.2 Extraterrestrial Physics and Stellar Phenomena - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 921 Mathematics

Database: Compendex

Indoor test method of attitude measurement accuracy of photoelectric theodolite

Tian, Liude1, 2; Liu, Chaohui1; Zhao, Jianke1; Duan, Yanxuan1, 2; Pan, Liang1; Zhao, Huaixue1; Duan, Jiong1; Long, Jiangbo1; Wang, Zhengfeng1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 8, August 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0812002; Article number: 0812002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In order to realize indoor test and evaluation of attitude measurement accuracy of range optical attitude measurement equipment, some research work has been done. The principle of intersection surveying the attitude of spatial axisymmetric target with photoelectric theodolites is introduced. The device is introduced to simulate the attitude of infinite object indoor, which is composed of measurement rack, collimator, light source, and targets with different angles. Precise mathematical model is established, which is relation with target attitude angle and azimuth and elevation of target feature points. Firstly, several feature points on the target are measured with high precision theodolite. Secondly, according to the above mathematical model, the target attitude is fitted by using the least square method, then, the target attitude angle is got. It has been proved that the calibration precision can reach 0.05°. Consider the calibration results as true value of the target attitude angle, dynamic measurements are performed on the same target by using photoelectric theodolite and attitude measurement error of the theodolite can be obtained in comparsion with two measurement results. (19 refs.)Main Heading: PhotoelectricityControlled terms: Calibration - Least squares approximations - Light sources - Mathematical models - Measurements - Tracking (position)Uncontrolled terms: Attitude measurement - Attitude measurement errors - Attitude simulation - Calibration precision - Dynamic measurement - Infinite objects - Least square methods - Photoelectric theodoliteClassification Code: 716.2 Radar Systems and Equipment - 741.1 Light/Optics - 744 Lasers - 921 Mathematics - 921.6 Numerical Methods - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

A new destriping method combining moment matching and interpolation in infrared images

Gong, Zhendong1, 2; Leng, Hanbing1; Cao, Jianzhong1; Wang, Jihong1, 2; Wu, Qingquan1, 2; Fan, Xinming1, 2; Zhao, Bing1, 2; Yang, Lei1; Liao, Jiawen1 Source: ICIST 2014 - Proceedings of 2014 4th IEEE International Conference on Information Science and Technology, p 410-413, October 10, 2014; ISBN-13: 9781479948086; DOI: 10.1109/ICIST.2014.6920504; Article number: 6920504; Conference: 2014 4th IEEE International Conference on Information Science and Technology, ICIST 2014, April 26, 2014 - April 28, 2014; Sponsor: Chinese Academy of Engineering; IEEE Beijing Section; The Chinese University of Hong Kong;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, CAS, Xi'an, Shaanxi Province, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Stripe noise is very common in uncooled infrared imaging systems and often severely degrades the image quality. Based on the analysis of existing methods, a new destriping method combining moment matching and interpolation was proposed. The method mainly consisted of three steps: Firstly, moment matching was used to eliminate most stripes. Then an adaptive algorithm was used to classify the left stripes into three types: one-pixel-width stripes, two-pixel-width stripes and local stripes. Finally, these left stripes were identified and removed with weighted multi-neighborhood interpolation. The algorithm was tested with IR images heavily polluted by stripe noises, and the result indicated that it could efficiently remove stripe noise and enhance the image quality significantly better than the single method discussed in literature. © 2014 IEEE. (8 refs.)Main Heading: Image matchingControlled terms: Adaptive algorithms - Image quality - Infrared imaging - Interpolation - Pixels - Thermography (imaging)Uncontrolled terms: Destriping - IR images - Moment-matching - Stripe noise - Uncooled InfraredClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 742.1 Photography - 742.2 Photographic Equipment - 746 Imaging Techniques - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

Real-time implementation of camera positioning algorithm based on FPGA & SOPC

Yang, Mingcao1, 2; Qiu, Yuehong1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9282, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413571; DOI: 10.1117/12.2068208; Article number: 92822K; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In recent years, with the development of positioning algorithm and FPGA, to achieve the camera positioning based on real-time implementation, rapidity, accuracy of FPGA has become a possibility by way of in-depth study of embedded hardware and dual camera positioning system, this thesis set up an infrared optical positioning system based on FPGA and SOPC system, which enables real-time positioning to mark points in space. Thesis completion include: (1) uses a CMOS sensor to extract the pixel of three objects with total feet, implemented through FPGA hardware driver, visible-light LED, used here as the target point of the instrument. (2) prior to extraction of the feature point coordinates, the image needs to be filtered to avoid affecting the physical properties of the system to bring the platform, where the median filtering. (3) Coordinate signs point to FPGA hardware circuit extraction, a new iterative threshold selection method for segmentation of images. Binary image is then segmented image tags, which calculates the coordinates of the feature points of the needle through the center of gravity method. (4) direct linear transformation (DLT) and extreme constraints method is applied to three-dimensional reconstruction of the plane array CMOS system space coordinates. using SOPC system on a chip here, taking advantage of dual-core computing systems, which let match and coordinate operations separately, thus increase processing speed. © 2014 SPIE. (9 refs.)Main Heading: Tracking (position)Controlled terms: Algorithms - Application specific integrated circuits - Binary images - Cameras - CMOS integrated circuits - Extraction - Field programmable gate arrays (FPGA) - Hardware - Image matching - Image processing - Image segmentation - Iterative methods - Light emitting diodes - Linear transformations - Manufacture - Mathematical transformations - Median filters - Optical testing - Real time control - System-on-chipUncontrolled terms: Center of gravity method - Direct linear transformation - Feature point extraction - Iterative threshold selections - Match-point - Positioning algorithms - Real-time implementations - Three-dimensional reconstructionClassification Code: 537.1 Heat Treatment Processes - 605 Small Tools and Hardware - 703.2 Electric Filters - 714.2 Semiconductor Devices and Integrated Circuits - 716.2 Radar Systems and Equipment - 721.3 Computer Circuits - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 731 Automatic Control Principles and Applications - 732 Control Devices - 741.3 Optical Devices and Systems - 742.2 Photographic Equipment - 802.3 Chemical Operations - 921 Mathematics

Database: Compendex

The recent development of fiber-optic chemical sensor

Wang, Jian1, 2, 3; Wei, Jian-Ping3; Yang, Bo4; Gao, Zhi-Yang4; Zhang, Li-Wei1; Yang, Xue-Feng1 Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, v 34, n 8, p 2035-2039, August 2014; Language: Chinese

; ISSN: 10000593; DOI: 10.3964/j.issn.1000-0593(2014)08-2035-05Author affiliation: 1 Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Key Lab. of Gas Geology and Gas Control, Henan Polytechnic University, Jiaozuo 454000, China4 School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China

Abstract: The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemicl sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introducded respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor. (36 refs.)Main Heading: Fiber optic chemical sensorsControlled terms: Fiber optics - Film preparation - Optical fibers - Sol-gel processUncontrolled terms: Chemical bondings - Development directions - Development trends - Flexible designs - Micro-structured optical fibers - Recent researches - Research focus - Sensor technologiesClassification Code: 712.1 Semiconducting Materials - 741.1.2 Fiber Optics - 813.1 Coating Techniques

Database: Compendex

Analysis and research of stereo correspondence algorithms

Li, Yan-Yun1, 2; Liu, Zhao-Hui2; Zhou, Liang1, 2 Source: Applied Mechanics and Materials, v 568-570, p 768-772, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.768;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, 710119, China2 University of Chinese Academy of Sciences, Beijing, 100039, China

Abstract: Stereo matching has been the focus of computer vision research. Some current researches on stereo matching algorithms were summarized, the stereo matching key techniques were analyzed; View of the current major challenges on binocular stereo matching, elaborated matching algorithm possible solutions and modification approaches; Finally, the field of technology development are prospected. © (2014) Trans Tech Publications, Switzerland. (19 refs.)Main Heading: Stereo image processingControlled terms: Algorithms - Binoculars - Computer vision - ResearchUncontrolled terms: Binocular matching - Binocular stereo - Disparity precision - Matching algorithm - Stereo correspondences - Stereo matching - Stereo matching algorithm - Technology developmentClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741.2 Vision - 741.3 Optical Devices and Systems - 901.3 Engineering Research - 921 Mathematics

Database: Compendex

Actively learning human gaze shifting paths for semantics-aware photo cropping

Zhang, Luming1; Gao, Yue2; Ji, Rongrong3; Xia, Yingjie4; Dai, Qionghai2; Li, Xuelong5 Source: IEEE Transactions on Image Processing, v 23, n 5, p 2235-2245, May 2014

; ISSN: 10577149; DOI: 10.1109/TIP.2014.2311658; Article number: 6766723;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Computing, National University of Singapore, Singapore, Singapore2 Tsinghua National Laboratory for Information Science and Technology, Department of Automation, Tsinghua University, Beijing 100084, China3 Department of Cognitive Science, School of Information Science and Engineering, Xiamen University, Xiamen 361000, China4 Hangzhou Institute of Service Engineering, Hangzhou Normal University, Zhejiang, China5 Center for OPtical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Photo cropping is a widely used tool in printing industry, photography, and cinematography. Conventional cropping models suffer from the following three challenges. First, the deemphasized role of semantic contents that are many times more important than low-level features in photo aesthetics. Second, the absence of a sequential ordering in the existing models. In contrast, humans look at semantically important regions sequentially when viewing a photo. Third, the difficulty of leveraging inputs from multiple users. Experience from multiple users is particularly critical in cropping as photo assessment is quite a subjective task. To address these challenges, this paper proposes semantics-aware photo cropping, which crops a photo by simulating the process of humans sequentially perceiving semantically important regions of a photo. We first project the local features (graphlets in this paper) onto the semantic space, which is constructed based on the category information of the training photos. An efficient learning algorithm is then derived to sequentially select semantically representative graphlets of a photo, and the selecting process can be interpreted by a path, which simulates humans actively perceiving semantics in a photo. Furthermore, we learn a prior distribution of such active graphlet paths from training photos that are marked as aesthetically pleasing by multiple users. The learned priors enforce the corresponding active graphlet path of a test photo to be maximally similar to those from the training photos. Experimental results show that: 1) the active graphlet path accurately predicts human gaze shifting, and thus is more indicative for photo aesthetics than conventional saliency maps and 2) the cropped photos produced by our approach outperform its competitors in both qualitative and quantitative comparisons. © 1992-2012 IEEE. (48 refs.)Main Heading: SemanticsControlled terms: Image processing - Mathematical modelsUncontrolled terms: active graphlet path - aesthetics - Efficient learning - Low-level features - Photo cropping - Prior distribution - Quantitative comparison - Sequential orderingClassification Code: 741 Light, Optics and Optical Devices - 903.2 Information Dissemination - 921 Mathematics

Database: Compendex

Searching algorithm of auto-focusing based on MTF auxiliary focal judgment

He, Zhen-Xin1; Liu, Chun-Tong1; Huang, Xian-Xiang1; Wu, Guo-Jun2; Zhang, Zhi-Li1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 4, April 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144304.0411002; Article number: 0411002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 State Key Discipline Laboratory of Armament Launch Theory and Technology, The Second Artillery Engineering University, Xi'an 710025, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Traditional climbing search algorithm cannot usually focusing accurately due to the interference of evaluation function local extremum effected by measure environment. A searching algorithm of auto-focusing based on MTF auxiliary focal judgment was introduced to improve the climbing method. Definition evaluation function and MTF values of images were considered at the same time. And based on those results, search direction was judged. Slanted-edge method was improved to calculate the image MTF values accurately based on the auto-selection of slanted-edge area. At last, the principle and implementation of the improved algorithm was given. In the theodolite auto-fousing system, the system imaging effect was validated, and different initial position and circumstance were considered using the proposed searching algorithm. The experiment results of theodolite auto-focus system show that the improved climbing search algorithm can effectively eliminate the local extremum disturbance, and make the system searching focusing accurately and reliably. (18 refs.)Main Heading: FocusingControlled terms: Function evaluation - Learning algorithmsUncontrolled terms: Auto-focus system - Auto-focusing - Climbing algorithms - Evaluation function - Search Algorithms - Search direction - Searching algorithms - Slanted-edge methodClassification Code: 711.1 Electromagnetic Waves in Different Media - 723 Computer Software, Data Handling and Applications - 921.6 Numerical Methods

Database: Compendex

Efficient search and localization of human actions in video databases

Shao, Ling1, 2; Jones, Simon2; Li, Xuelong3 Source: IEEE Transactions on Circuits and Systems for Video Technology, v 24, n 3, p 504-512, March 2014

; ISSN: 10518215; DOI: 10.1109/TCSVT.2013.2276700; Article number: 6575133;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 ,Jiangsu, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom3 Center for Optical Imagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: As digital video databases grow, so grows the problem of effectively navigating through them. In this paper we propose a novel content-based video retrieval approach to searching such video databases, specifically those involving human actions, incorporating spatio-temporal localization. We outline a novel, highly efficient localization model that first performs temporal localization based on histograms of evenly spaced time-slices, then spatial localization based on histograms of a 2-D spatial grid. We further argue that our retrieval model, based on the aforementioned localization, followed by relevance ranking, results in a highly discriminative system, while remaining an order of magnitude faster than the current state-of-the-art method. We also show how relevance feedback can be applied to our localization and ranking algorithms. As a result, the presented system is more directly applicable to real-world problems than any prior content-based video retrieval system. © 2014 IEEE. (43 refs.)Main Heading: Image retrievalControlled terms: Graphic methods - Multimedia systems - Video recordingUncontrolled terms: Content-based video retrieval - Content-based video retrieval systems - Human actions - Relevance feedback - spatiotemporal localization - State-of-the-art methods - Temporal localization - Video retrievalClassification Code: 716.4 Television Systems and Equipment - 723.5 Computer Applications - 741 Light, Optics and Optical Devices

Database: Compendex

Best slant-plane estimation based stereo matching algorithm

Cao, Xiaoqian1, 2; Ma, Caiwen1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 973-978, March 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechenics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: A novel stereo matching algorithm based on best slant-plane estimation was proposed in this paper in the purpose of eliminating "stair-casing" which showed up frequently in the slant scene matching process where the window -based matching algorithm was used. In this procedure, a slant parameter vector was randomly attributed to every pixel in the reference image firstly, then, those vectors were iteratively propagated between neighbor pixels followed by a recursively slant-plane parameter refinement process for each pixels in the principle of whether a lower cost could be got under the new slant-plane parameter vectors, until the parameter vectors were converged to the best slant-plane parameter vectors while a sub-pixel disparity was got for each pixel in the reference image. Experiment results indicate the effectiveness of the algorithm, the performance of the algorithm on the slant scene is ranked on top of those state-of-art algorithm which is relatively close to the algorithm proposed here, while the performance on the normal scene is comparable with the state-of -art algorithm. (13 refs.)Main Heading: AlgorithmsControlled terms: Image processing - Iterative methods - Pixels - Stairs - Stereo image processing - VectorsUncontrolled terms: Matching algorithm - Parameter refinement - Parameter vectors - Slant plane evaluation - Stair-casing - Stereo matching - Stereo matching algorithm - Sub-pixel disparityClassification Code: 402 Buildings and Towers - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Laser wave-front measuring based on quadri-wave lateral shearing interferometry

Ren, Juan1, 2; Luo, Xiu Juan1; Xia, Ai Li1; Zhang, Yu1, 2 Source: Applied Mechanics and Materials, v 568-570, p 50-54, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.50;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Quadri-wave lateral shearing interferometry(QWLSI) is a new and powerful technique for wave-front measurement. This paper deduced the principle of QWLSI in details, showed a Fourier analysis of the resulting interferogram, then obtained a wave-front with high accuracy and minimum reconstruction error by using the least square method. Finally a 532nm laser was measured to validate the reconstruction, and the error analysis was discussed in practical laser metrology. It is concluded that QWLSI provides a better choice for the adaptive optics as compared with traditional lateral shearing interferometer(TLSI) and Shack-Hartmann(S-H) wave-front sensor. © (2014) Trans Tech Publications, Switzerland. (8 refs.)Main Heading: InterferometryControlled terms: Adaptive optics - Fourier analysis - Least squares approximations - Shearing - Units of measurement - WavefrontsUncontrolled terms: Hartmann - Laser metrology - Lateral shearing interferometer - Lateral shearing interferometry - Least square methods - Reconstruction error - Wave front reconstruction - Wave front sensorsClassification Code: 604.1 Metal Cutting - 711 Electromagnetic Waves - 731.1 Control Systems - 751 Acoustics, Noise. Sound - 752 Sound Devices, Equipment and Systems - 902.2 Codes and Standards - 921 Mathematics - 921.6 Numerical Methods - 941.4 Optical Variables Measurements

Database: Compendex

Rytov variance equivalence through extended atmospheric turbulence and an arbitrary thickness phase screen in non-Kolmogorov turbulence

Zeng, Zhihong1, 2; Luo, Xiujuan1; Xia, Aili1; Zhang, Yu1, 2; Sun, Chuangdong1 Source: Optik, v 125, n 15, p 4092-4097, August 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.01.106;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences (CAS), Xi'an 710119, China2 Graduate University of CAS, Beijing 100049, China

Abstract: An arbitrary thickness phase screen model can describe scintillation index for Gaussian beam propagating through a phase screen more accurate than thin phase screen model. To describing actual scintillation index for Gaussian beam propagating through an extended medium using a phase screen in weak non-Kolmogorov turbulence, the scintillation index and Rytov variance for arbitrary thickness phase screen model are derived. Specially, the ratio of the Rytov variances for a phase screen and extended random media is found under the assumption of equivalence in scintillation index of the two cases. The theoretical results show that the normalized Rytov variance varies with the power law of the turbulence spectrum, the relative thickness of the phase screen, the position of the phase screen, the transmitter beam parameters and the radial position at output plane. The influences of these variables are also simulated. These results will be applied to simulation of adaptive optics and laser communication. © 2014 Elsevier GmbH. (15 refs.)Main Heading: ScintillationControlled terms: Atmospheric turbulence - Gaussian beams - Turbulence modelsUncontrolled terms: Beam parameter - Non-Kolmogorov turbulences - Phase screen - Radial position - Relative thickness - Rytov variance - Scintillation index - Turbulence spectrumClassification Code: 443.1 Atmospheric Properties - 711 Electromagnetic Waves - 741.1 Light/Optics

Database: Compendex

Simulation study on slant-to-vertical deviation in two dimensional TEC mapping over the ionosphere equatorial anomaly

Yu, Tao1, 2; Mao, Tian2; Wang, Yungang2; Zeng, Zhongcao2; Xia, Chunliang1; Wu, Fenglei3; Wang, Le4 Source: Advances in Space Research, v 54, n 4, p 595-603, August 15, 2014

; ISSN: 02731177, E-ISSN: 18791948; DOI: 10.1016/j.asr.2014.04.015;

Publisher: Elsevier LtdAuthor affiliation: 1 Institute of Geophysics and Geomatics, China University of Geosciences, No. 388 Lumo Road, Wuhan 430074, China2 National Center for Space Weather, China Meteorological Administration, Zhong-guan-cun South Str. 46#, Haidian District, Beijing 100081, China3 Beijing Aerospace Control Center, Beijing, China4 Xi'An Institute of Optics and Precision Mechanics of CAS, China

Abstract: With the rapid increase of GPS/GNSS receivers being deployed and operated in China, real-time GPS data from nearly a thousand sites are available at the National Center for Space Weather, China Meteorology Administration. However, it is challenging to generate a high-quality regional total electron content (TEC) map with the traditional two-dimensional (2-D) retrieval scheme because a large horizontal gradient has been reported over east-south Asia due to the northern equatorial ionization anomaly. We developed an Ionosphere Data Assimilation Analysis System (IDAAS), which is described in this study, using an International Reference Ionosphere (IRI) model as the background and applying a Kalman filter for updated observations. The IDAAS can reconstruct a three-dimensional ionosphere with the GPS slant TEC. The inverse slant TEC correlates well with observations both for GPS sites involved in the reconstruction and sites that are not involved. Based on the IDAAS, simulations were performed to investigate the deviation relative to the slant-to-vertical conversion (STV). The results indicate that the relative deviation induced by slant-to-vertical conversion may be significant in certain instances, and the deviation varies from 0% to 40% when the elevation decreases from 90° to 15°, while the relative IDAAS deviation is much smaller and varies from -5% to 15% without an elevation dependence. Compared with 'true TEC' map derived from the model, there is large difference in STV TEC map but no obvious discrepancy in IDAAS map. Generally, the IDAAS TEC map is much closer to the "true TEC" than is STV TEC map is. It is suggested that three-dimensional inversion technique is necessary for GPS observations of low elevation at an equatorial anomaly region, wherein the high horizontal electron density gradient may produce significant slant-to-vertical deviations using the two-dimensional STV inversion method. © 2014 COSPAR. Published by Elsevier Ltd. All rights reserved. (31 refs.)Main Heading: Ionospheric measurementControlled terms: Data processing - Global positioning system - Ionosphere - Mapping - Two dimensionalUncontrolled terms: Data assimilation - Deviation - Electron-density gradients - Equatorial ionization anomaly - International reference ionospheres - Simulation studies - Total electron content - Two Dimensional (2 D)Classification Code: 711.1 Electromagnetic Waves in Different Media - 716.3 Radio Systems and Equipment - 723.2 Data Processing and Image Processing - 723.5 Computer Applications - 902.1 Engineering Graphics

Database: Compendex

Design and implementation of serial rapidio based on DSP and FPGA

Liu, Jun1, 2; Tian, Yan1; Hao, Wei1; Qu, Lei1, 2 Source: Advanced Materials Research, v 971-973, p 1581-1585, 2014, New Technologies for Engineering Research and Design in Industry

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038351412; DOI: 10.4028/www.scientific.net/AMR.971-973.1581; Conference: 2014 International Conference on Mechatronics and Intelligent Materials, MIM 2014, May 18, 2014 - May 19, 2014; Sponsor: CEIS; IFST; National Chin-Yi University of Technology; Scientific.Net;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 XI'AN Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In order to meet the request of high-speed data exchange in embedded systems, this paper details the high-speed SRIO (Serial RapidIO) interface protocol and the process of SRIO access timing between the local endpoint devices and the remote endpoint devices. And also we implement the design of the new high-performance RapidIO interconnection between DSP and FPGA. Through the performance testing of SRIO data transmission system, experimental results show that the design can stably transfer data at high speed between processors. © (2014) Trans Tech Publications, Switzerland. (7 refs.)Main Heading: Digital signal processingControlled terms: Design - Electronic data interchange - Embedded systems - Field programmable gate arrays (FPGA) - Network protocolsUncontrolled terms: Design and implementations - DSP - High Speed - High-speed data - Interface protocol - Performance testing - RapidIO - SRIOClassification Code: 408 Structural Design - 721.3 Computer Circuits - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing

Database: Compendex

A method for ShenguangIII diagnostic instrument manipulator high precision automatic aiming

Wang, Wei1; Wang, Zheng-Zhou1; He, Jun-Hua1; Zhang, Min1; Wei, Ming-Zhi1; Yan, Ya-Dong1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 6, June 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144306.0612002; Article number: 0612002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: In order to realize diagnostic instrument manipulator precise targeting, an aiming method based on visual servoing was proposed. Defined the target deviation and projection matrix in the vision system, the calculated target deviation value computed by projection matrix was closed to the true value. Using a 3-DOF hybrid mechanism motion mode, the motion accuracy was promoted. With optimizing visual servoing strategy based on projection matrix and motion mode, the total targeting work was greatly simplified, making the vision system calibration unnecessary. Automatic positioning tests indicate that pointing accuracy is 11μm in X direction and 12 μm in Y direction. Radical positioning accuracy is 14 μm. Laser shot tests with streak camera show that the automatic aiming method can satisfy the requirements of project. (10 refs.)Main Heading: ManipulatorsControlled terms: Computer vision - Instruments - Visual servoingUncontrolled terms: Hybrid mechanisms - Motion accuracy - Motion modes - Pointing accuracy - Positioning accuracy - Projection matrix - Target deviation - Vision systemsClassification Code: 731 Automatic Control Principles and Applications - 732 Control Devices - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Method of focal length measurement for infrared optical system with long focal length

Yao, Zhen1, 2; Wu, Yiming1; Gao, Limin1; Wu, Cuigang1; Mei, Chao1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 6, p 1950-1954, June 2014; Language: Chinese

; ISSN: 10072276;

Abstract: In strong laser host device, various optical lens with different focal length are needed to expand and collimate the beam, the accurate of the lens'focal length directly affect the overall performance of the system, so it is particularly important to accurately measure the focal length of lens. A new method of measuring the infrared optical system with long focal length by using the Hartmann- Shack wave-front detected device and rotated plane mirror was proposed. The measuring principle of the system was given. Using optical simulation software ZEMAX, the influence of different aperture on the measurement of focal length was analyzed. Then the relationship between the rotation angle of the plane mirror and the system measurement error was deducted by using error theory. Finally the experiment was done to obtain the real result, the result of measurement shows that when the plane mirror rotated to a certain angle, set an appropriate optical aperture, the system measurement precision can be better than 3&permil;, much higher than the traditional measuring method. In addition, the measurement method is also conveniently to use, high stability in measure, etc.. (7 refs.)Main Heading: Optical systemsControlled terms: Computer software - Error analysis - Mirrors - WavefrontsUncontrolled terms: Focal length measurements - Infrared optical systems - Long focal length measurements - Long focal lengths - Measurement methods - Stability in measure - System measurement - System measurement precisionClassification Code: 711 Electromagnetic Waves - 723 Computer Software, Data Handling and Applications - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

Low-cost multipoint liquid-level sensor with plastic optical fiber

Lin, Xiao1; Ren, Liyong1; Xu, Yiping1; Chen, Nana1; Ju, Haijuan1; Liang, Jian1; He, Zhengquan1; Qu, Enshi1; Hu, Baowen1; Li, Yulin1 Source: IEEE Photonics Technology Letters, v 26, n 16, p 1613-1616, August 15, 2014

; ISSN: 10411135; DOI: 10.1109/LPT.2014.2329037; Article number: 6826547;

Abstract: A simple and low-cost discrete liquid-level measurement system is present in this letter. It consists of a group of plastic optical fiber segments, which are aligned coaxially and spaced equally. When the spacing between every two adjacent fiber segments is filled with liquid, the light power will be easier to couple from one segment to the next as compared with the situation that the fibers are exposed in air. Based on this point, we design this intensity-based sensor and investigate its working properties theoretically by using the ray-tracing method. The performance of this sensor is demonstrated in detail where different liquids are utilized as specimens. © 2014 IEEE. (13 refs.)Main Heading: Plastic optical fibersControlled terms: Fiber optic sensors - Plastics - Ray tracingUncontrolled terms: Fiber segments - Intensity-based sensors - Light power - Liquid level sensors - Measurement system - Optical fiber sensor - Ray-tracing method - Working propertiesClassification Code: 741.1 Light/Optics - 741.1.2 Fiber Optics - 817.1 Polymer Products

Database: Compendex

Improved non-negative tensor Tucker decomposition algorithm for interference hyper-spectral image compression

Wen, Jia1, 2; Zhao, JunSuo1; Ma, CaiWen2; Wang, CaiLing3 Source: Science China Information Sciences, December 20, 2014

; ISSN: 1674733X; DOI: 10.1007/s11432-014-5165-x;

Publisher: Science in China Press Article in PressAuthor affiliation: 1 Science and Technology on Integrated Information System Laboratory, Institute of Software, Chinese Academy of Sciences, Beijing, China2 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China3 College of Computer Science, Xian Shiyou University, Xian, China

Abstract: The compression method, first proposed in 2012, is based on the non-negative tensor decomposition for interference hyper-spectral image data. As a tensor is generated by a huge amount of interference hyper-spectral images, the multiplicative update algorithm is made extremely complicated, and even unfeasible. To reduce the computational cost and speed up the convergence, this paper, based on the characteristics of interference hyper-spectral images, develops a new algorithm using different down-sampling factors for different non-negative wavelet sub-band tensors. The experimental results showed that this algorithm could significantly shorten the running time, while maintaining a good compression performance compared with the conventional methods.Main Heading: TensorsControlled terms: Algorithms - Image compression - Interference suppression - Spectroscopy - Wavelet decompositionUncontrolled terms: Compression performance - Conventional methods - Hyper-spectral images - LASIS - Lifting wavelet transforms - Multiplicative updates - Non-negative tensor decompositions - Tucker decompositionsClassification Code: 711 Electromagnetic Waves - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 801 Chemistry - 921 Mathematics

Database: Compendex

Switchable dual-wavelength fiber laser mode-locked by carbon nanotubes

Chen, G.W.1; Li, W.L.1; Yang, H.R.1; Kong, Y.C.1 Source: Journal of Modern Optics, November 23, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.982224;

Publisher: Taylor and Francis Ltd. Article in PressAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: We have proposed a switchable mode-locked fiber laser by means of carbon nanotube saturable absorber and fiber Bragg gratings (FBGs). The single-wavelength mode-locking operation can be switched between 1549.5 and 1559.5 nm, respectively, which correspond to the central wavelengths of two FBGs. With the appropriate setting of polarization controller, the stable dual-wavelength operation can be achieved due to the high stability of saturable absorber based on carbon nanotubes. Our method provides a simple, stable, low-cost, dual-wavelength ultrafast-pulsed source.Main Heading: Mode-locked fiber lasersControlled terms: Carbon - Carbon nanotubes - Fiber Bragg gratings - Fiber lasers - Fibers - Locks (fasteners) - Nanotubes - Saturable absorbers - YarnUncontrolled terms: Central wavelength - Dual wavelength - FBGs - Fiber Bragg gratings (FBGs) - Polarization controllers - Single wavelength - Switchable - Switchable dual wavelengthsClassification Code: 601.3 Mechanisms - 741.1.2 Fiber Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 819.4 Fiber Products

Database: Compendex

Laser pulse shaping technology based on semiconductor laser

Lin, Ping1, 2; Liu, Baiyu1; Gou, Yongsheng1; Bai, Yonglin1; Wang, Bo1; Bai, Xiaohong1; Qin, Junjun1; Zhu, Bingli1; Yang, Wenzheng1; Zhu, Shaolan1; Gao, Cunxiao1; Ouyang, Xian1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 103-107, January 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of the Chinese Academy of Sciences, Beijing 100049, China

Abstract: Pulse shaping technique is of great significance for high power laser facility. In this paper, a new method used in laser pulse shaping system was proposed. An arbitrary waveform generator was fabricated to generate shaping electrical pulse. GaAs Field Effect Transistor (FET) has good ability of generating voltage-controlled current and on-off characteristic, while the semiconductor laser contains direct modulate characteristic. The unit-pulse was generated based on the on-off characteristic of GaAs FET, and then the arbitrary waveform electrical pulse was generated by stacking a set of unit-pulses. Impedance tapered micro-strip line was designed to maintain the consistency of each unit-pulse. The arbitrary waveform electrical pulse was used as shaping electrical pulse to modulate the semiconductor laser directly to realize the laser pulse shaping. With this method, a laser pulse waveform was generated with duration less than 10 ns, 330 ps time-domain adjustment. The experiment results show that the shaped laser pulse is determined only by shaping electrical pulse. (12 refs.)Main Heading: Pulse generatorsControlled terms: Electric generators - Field effect transistors - Gallium arsenide - High power lasers - Laser pulses - Pulse shaping - Semiconducting gallium - Semiconductor lasers - Time domain analysisUncontrolled terms: Arbitrary waveform - Arbitrary waveform generator - GaAs-FET - High power laser facility - Microstripes - On-off characteristic - Pulse shaping techniques - Voltage-controlledClassification Code: 921 Mathematics - 804 Chemical Products Generally - 744.1 Lasers, General - 714.2 Semiconductor Devices and Integrated Circuits - 713.4 Pulse Circuits - 712.1.1 Single Element Semiconducting Materials - 705.2 Electric Generators

Database: Compendex

High quality image resizing

Wang, Qi1; Yuan, Yuan2 Source: Neurocomputing, v 131, p 348-356, May 5, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.09.032;

Publisher: ElsevierAuthor affiliation: 1 Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: An increasing amount of display devices with fixed sizes call for an adaptive strategy for optimal display. For this purpose, content aware image resizing techniques are developed. Previous works mainly lay their attention on the shrinkage operation of the examined image. Less efforts are paid on the expansion manipulation. Though some literatures claim an extension of their shrinkage operation to expanding the image in a similar way, the obtained results are not satisfying. In this paper, a high quality image resizing method is proposed to retain the details when stretching an image. Instead of using interpolation based techniques which are taken for granted by existing methods, an expansion model is first learned from a set of training images. Then the future enlargement is based on this principle. Experiments on two publicly available datasets demonstrate the effectiveness of the presented method. A further extension on video enlargement is also presented as an example. Though the proposed method is formulated in the context of seam carving, it can be readily extended to other techniques such as cropping, segmentation and warping based resizing methods. © 2014. (42 refs.)Main Heading: ShrinkageControlled terms: Display devicesUncontrolled terms: Adaptive strategy - Content-aware image resizing - Dictionary learning - High quality images - Image resizing - Saliency - Seam carving - Training imageClassification Code: 722.2 Computer Peripheral Equipment - 951 Materials Science

Database: Compendex

Terahertz spectral investigation of anhydrous and monohydrated glucose using terahertz spectroscopy and solid-state theory

Zheng, Zhuan-Ping1; Fan, Wen-Hui1; Li, Hui1; Tang, Jie1 Source: Journal of Molecular Spectroscopy, v 296, p 9-13, February 2014

; ISSN: 00222852, E-ISSN: 1096083X; DOI: 10.1016/j.jms.2013.12.002;

Abstract: The terahertz absorption spectra of anhydrous and monohydrated glucose have been investigated and compared by using THz spectroscopy and solid-sate density functional theory. The unrevealed mechanism of THz spectral differences of both materials measured has been analyzed based on the crystalline structure. Solid-state calculations of the THz characteristic spectra using Perdew-Burke-Ernzerhof functional have provided the satisfactory spectral reproduction for these two materials. It is found that the characterized features of monohydrated glucose mainly come from the intermolecular modes of water-glucose and glucose-glucose molecules, while those of anhydrous glucose origin from the interactions of glucose molecules. © 2013 Elsevier Inc. All rights reserved. (27 refs.)Main Heading: GlucoseControlled terms: MoleculesUncontrolled terms: Crystalline structure - Glucose molecules - Intermolecular modes - Perdew-burke-ernzerhof - Spectral differences - Terahertz absorption spectrum - Thz spectroscopy - THz-TDSClassification Code: 804.1 Organic Compounds - 931.3 Atomic and Molecular Physics

Database: Compendex

A simple, polymer-microfiber-assisted approach to fabricating the silica microfiber knot resonator

Xu, Yiping1, 2; Ren, Liyong1; Liang, Jian1; Ma, Chengju1, 2; Wang, Yingli1; Chen, Nana1, 2; Qu, Enshi1 Source: Optics Communications, v 321, p 157-161, September 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.01.077;

Abstract: With the assistance of the polymer microfiber, we propose a simple approach to fabricating silica-based optical microfiber knot resonators (MKRs) in this paper. A pre-fabricated knot ring made of the polymer microfiber can be readily driven to the silica microfiber owing to the intensive van der Waals and the electrostatic forces between the polymer and the silica microfibers. The fabrication process is introduced in detail. Several kinds of MKRs are fabricated and their optical performances are demonstrated accordingly. © 2014 Elsevier B.V. (28 refs.)Main Heading: SilicaControlled terms: Fabrication - Optical fibers - Polymers - Resonators - Van der Waals forcesUncontrolled terms: Fabrication process - Micro-fiber - Micro-fiber knot resonators - Microfibers - Optical performance - Simple approach - Van der waalsClassification Code: 714 Electronic Components and Tubes - 741.1.2 Fiber Optics - 801.4 Physical Chemistry - 812 Ceramics, Refractories and Glass - 815.1 Polymeric Materials - 913.4 Manufacturing

Database: Compendex

Hybrid structure for robust dimensionality reduction

Lu, Xiaoqiang1; Yuan, Yuan1 Source: Neurocomputing, v 124, p 131-138, January 26, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.07.019;

Publisher: ElsevierAuthor affiliation: 1 The Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: In recent years, dimensionality reduction has attracted a great deal of attention in the communities of machine learning and data mining. The basic goal of dimensionality reduction is to discover the low dimensional manifold embedded in a high dimensional space. Although some existing manifold learning algorithms (ISOMAP, LE, LLE, LTSA, etc.) can capture the local structure of data manifold, they have poor performance in some recognition tasks. This is mainly because that they cannot handle well with the "out of sample" problem. Moreover, these algorithms are sensitive to the choice of nearest neighbors, which is crucial in classification. To address these problems, this paper proposes a Robust Dimensionality Reduction Algorithm With Local and Global Structure (RLGS) based on a novel adaptive weighting mechanism. Hybrid structure of local and global structures is studied. By using the adaptive weight, RLGS has the capacity of adaptively exploiting non-linear structure of data manifold and is robust to parameters. Experiments demonstrate that RLGS performs better on public face databases compared with other reported algorithms. © 2013 Elsevier B.V. (37 refs.)Main Heading: Data miningControlled terms: Face recognition - Learning algorithms - Pattern recognition - Unsupervised learningUncontrolled terms: Adaptive weighting - Dimensionality reduction - Dimensionality reduction algorithms - High dimensional spaces - Low-dimensional manifolds - Manifold learning - Manifold learning algorithm - Nonlinear structureClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications

Database: Compendex

Visual simulation for space-telescope by coordinate transform

Cui, Kai1, 2; Liu, Zhaohui1; Li, Zhiguo1, 2; Liang, Dongsheng1, 2; Yuan, Hui1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 2, p 557-561, February 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy Science, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Visual simulation is useful for designing, analyzing and testing a space-telescope on the ground. Based on the coordinate transformation theory and the equal-angle projection method, visible boundary of the telescope was deduced for different orientation, and the two-dimension visual simulation was carried out using a real star catalog and the world coast line data. Reasonable results show that when the space-telescope is pointing to the high latitude area, a distortion of the round visible boundary appears in the Equidistant Cylindrical Projection style map chart. And the visible area on the earth surface is expanded when the height of the space-carrier increases. The simulation was used to imitate the celestial background in a real testing of a space-telescope outdoor. It's useful in testing and providing space environment for space-telescope on the ground. (9 refs.)Main Heading: Earth (planet)Controlled terms: Metadata - Telescopes - VisualizationUncontrolled terms: Co-ordinate transform - Co-ordinate transformation - Cylindrical projection - Equal-angle projection - Projection method - Space environment - Visible boundary - Visual simulationClassification Code: 657 Space Physics - 723 Computer Software, Data Handling and Applications - 902.1 Engineering Graphics

Database: Compendex

Four dimensional spectral imager with integral field fiber bundle

Li, Libo1, 2; Feng, Yutao1; Wang, Shuang1; Bai, Qinglan1; Hu, Bingliang1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 5, May 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0511004; Article number: 0511004;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of optics and precision mechanics of CAS, Xi'an, Shaanxi 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: As one of the most important development of remote sensing, spectral imager has been widely used in military, geognosy, ocean and atmosphere measurement. However, the classic spectral imager, neither dispersive spectral imager nor Fourier transform spectrometer, which has to take multiple exposures to scan spectral data cube, do not suit with the situation that the scene change too fast. Four-dimensional (4D) fiber reformatting spectral imager, in which a special optical fiber bundle sits in the image plane of the telescope and has linearly aligned at the entrance to the spectrograph, can capture three-dimensional (3D) spectral data cube in a single exposure. So it enable to measure fast moving target or fast changing scene. A breadboard system in the laboratory is described, the average spectral resolution of the system is 4.2 nm in visible range, and a good imaging result of color target is got. The fiber bundle errors are analyzed, and the calibrating method is given. (14 refs.)Main Heading: SpectroscopyControlled terms: Fibers - Optical fibersUncontrolled terms: Fast changing scene - Fiber bundles - Fourier transform spectrometers - Moving targets - Multiple exposure - Single exposure - Special optical fibers - Spectral imagerClassification Code: 741.1.2 Fiber Optics - 801 Chemistry - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

A high-efficiency tunable polarization-insensitive wavelength convertor based on degenerate four-wave mixing in a highly nonlinear photonic crystal fiber

Huang, Xinning1, 2; Xie, Xiaoping1; Zhao, Wei1; Han, Biao1; Feng, Huan1 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 5, May 2014

; ISSN: 02587025; DOI: 10.3788/CJL201441.0505005; Article number: 0505005;

Publisher: Science PressAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: A high-efficiency tunable polarization-insensitive all-optical wavelength convertor for 10 Gb/s return-to-zero on-off keying (RZ-OOK) signals using degenerate four-wave mixing (FWM) in a highly nonlinear photonic crystal fiber (PCF) is demonstrated. The residual birefringence in the 50 m dispersion-flattened PCF with 11 W-1·km-1 nonlinear coefficient guarantees the FWM-based wavelength conversion to be polarization-insensitive when the pump polarization is exactly at 45° to the birefringent axes of the PCF. Experimental results show that with 45° pump launch, the polarization dependence of FWM in the PCF can be decreased to less than 0.6 dB over the entire 25 nm conversion bandwidth. The optical signal-to-noise ratios (OSNR) of the converted signals are better than 40 dB and the conversion efficiencies are better than -15 dB over the conversion range with 10 Gb/s signal polarization-scrambled. (14 refs.)Main Heading: PolarizationControlled terms: Birefringence - Four wave mixing - Nonlinear optics - Optical frequency conversion - Optical signal processing - Photonic crystal fibers - Photonic crystalsUncontrolled terms: Degenerate four wave mixing - Highly nonlinear photonic crystal fiber - Highly nonlinear photonic crystal fibers (PCF) - Nonlinear coefficient - Optical signal to noise ratio - Polarization dependence - Polarization-insensitive - Residual birefringenceClassification Code: 703 Electric Circuits - 741 Light, Optics and Optical Devices - 951 Materials Science

Database: Compendex

An improved hough transform algorithm based on pyramid method

Ren, Long1; Liao, Jia Wen1; Cao, Jian Zhong1; Wang, Hua1; Zhao, Xiao Dong1; Meng, Han1 Source: Applied Mechanics and Materials, v 543-547, p 1917-1921, 2014, Vehicle, Mechatronics and Information Technologies II

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350606; DOI: 10.4028/www.scientific.net/AMM.543-547.1917; Conference: International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2014, February 19, 2014 - February 20, 2014; Sponsor: INTIEA Information and Engineering; Scientific.Net; Trans Tech publications inc.; National Institute of Technology Rourkela; Universitatea Politehnica Din Bucuresti; et al;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and precision Mechanics Chinese Academy of Sciences, China

Abstract: Hough Transform [1] has become a common method in the usage of line detection because of its robustness. It is important in computer vision and image analysis. Usually, the standard Hough transform method(SHT) transform the points in image space into parameter space and vote for all the possible patterns passing through that point. But, there are two serious problems in the standard method of line detection. The first is the high computation complexity and the second is the large storage requirements.In order to solve the two problems, this paper raise a fast- Hough transform algorithm base on pyramid algorithm. First of all we need to desample the primitive binary image with n times; and execute the Hough transform in the nth level image to get the parameter of straight line in this image, which is used in the n-1 level image. Finally we can get the parameter of lines in the primitive image. Experiments show that this method can extremely reduces the computational time. © (2014) Trans Tech Publications, Switzerland. (12 refs.)Main Heading: Hough transformsControlled terms: Algorithms - Feature extraction - Image processing - Information technologyUncontrolled terms: Component - Computation complexity - Computational time - Hough transform algorithms - Image desample - Line detection - Pyramid method - Standard hough transformsClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 903 Information Science - 921 Mathematics - 921.3 Mathematical Transformations

Database: Compendex

Double constrained NMF for hyperspectral unmixing

Lu, Xiaoqiang1; Wu, Hao2; Yuan, Yuan1 Source: IEEE Transactions on Geoscience and Remote Sensing, v 52, n 5, p 2746-2758, May 2014

; ISSN: 01962892; DOI: 10.1109/TGRS.2013.2265322; Article number: 6553069;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Center for Optical Imagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, China2 Faculty of Mathematics and Computer Science, Hubei University, Wuhan 430062, China

Abstract: Given only the collected hyperspectral data, unmixing aims at obtaining the latent constituent materials and their corresponding fractional abundances. Recently, many nonnegative matrix factorization (NMF)-based algorithms have been developed to deal with this issue. Considering that the abundances of most materials may be sparse, the sparseness constraint is intuitively introduced into NMF. Although sparse NMF algorithms have achieved advanced performance in unmixing, the result is still susceptible to unstable decomposition and noise corruption. To reduce the aforementioned drawbacks, the structural information of the data is exploited to guide the unmixing. Since similar pixel spectra often imply similar substance constructions, clustering can explicitly characterize this similarity. Through maintaining the structural information during the unmixing, the resulting fractional abundances by the proposed algorithm can well coincide with the real distributions of constituent materials. Moreover, the additional clustering-based regularization term also lessens the interference of noise to some extent. The experimental results on synthetic and real hyperspectral data both illustrate the superiority of the proposed method compared with other state-of-the-art algorithms. © 1980-2012 IEEE. (47 refs.)Controlled terms: algorithm - data set - noise - pixel - spectral analysisClassification Code: 71.8.5.4 Remote sensing: numerical and image analysis

Database: GEOBASE

Design of infrared imaging system with adaptive correction function

Wang, Huawei1, 2; Cao, Jianzhong1; Ma, Caiwen1; Zhang, Hui1; Wu, Dengshan1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 61-66, January 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: In view of the fact that the response of IRFPA will drift with time and temperature and the IR imaging system will be used to measure and watch, an long-wave infrared uncooled imaging system which has adaptive correction function was designed. The system is based on FPGA, in which FPGA performs system control and image processing. Architecture of the system is simple and with less power dissipation. In order to improve the performance of the detector, a temperature control circuit based on ADN8830 was introduced, which could set temperature of the detector to a fixed point. In order to correct non-uniform responses of the detector' s individual elements, an adaptive non-uniformity correction algorithm was proposed based on shutter, which could compensate the response drift according to temperature and time. The system had both analog and digital video output, in which analog video could be used to watch, while digital video with 12 bit precision could be used to measure. The results show that the imaging system has the advantages of good image quality, good environmental adaptability and low power consumption. (8 refs.)Main Heading: Imaging systemsControlled terms: Computer graphics - Detectors - Field programmable gate arrays (FPGA) - Image processing - Infrared imaging - Multimedia systems - WatchesUncontrolled terms: Adaptive - Environmental adaptability - IRFPA - Low-power consumption - Nonuniformity - Nonuniformity correction - Shutter - Temperature control circuitClassification Code: 721.3 Computer Circuits - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 746 Imaging Techniques - 914 Safety Engineering - 943.3 Special Purpose Instruments

Database: Compendex

Design of space optical system with double infrared waveband based on image space scanning

Li, Gang1, 2; Fan, Xuewu1; Zou, Gangyi1, 2; Wang, Hongjuan1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 861-866, March 2014; Language: Chinese

; ISSN: 10072276;

Abstract: The design of optical systems with wide ground coverage are restricted by the size of infrared detector. This problem can be solved by choosing the appropriate imaging mode. A kind of image space scanning method was given in the paper. It could satisfy the optical systems with general area infrared detectors. The picture was built by image mosaics technology. Because the image space scanning method needs to be done in the parallel light path, the design method of three-mirror afocal system was studied based on two-mirror afocal system and the formulas to compute the initial structure was given. The optical system consists of afocal system, scanning mirror and imaging part. The scanning mirror was placed at the exit pupil of the afoacl system. The MWIR and LWIR were separated by the field-bias method and imaged respectively. The simulation analysis shows that the Narcissus is under control and the MTF of the optical system is very close to the diffraction limit. (7 refs.)Main Heading: Optical systemsControlled terms: Diffraction - Infrared detectors - Mirrors - Optical design - Scanning - Space telescopesUncontrolled terms: Diffraction limits - Image space - Initial structures - Scanning methods - Simulation analysis - Space optical system - Three-mirror afocal system - WavebandsClassification Code: 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Three-DOF manipulator kinematics and dynamics analysis and simulation

Shi, Heng1; Liang, Yan-Bing1 Source: Shanghai Jiaotong Daxue Xuebao/Journal of Shanghai Jiaotong University, v 48, p 28-32, October 28, 2014; Language: Chinese

; ISSN: 10062467;

Publisher: Shanghai Jiao Tong UniversityAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: A 3-DOF manipulator is modeled in ADAMS. In MATLAB, inverse kinematics is solved by geometric method. The desired trajectory, angular velocity and angular acceleration of each joint are obtained by the high order polynomial interpolation to complete the kinematics planning of the manipulator. Kinematics equations were got by D-H method and dynamics equations were obtained by Lagrangian method according to angular variables, velocity and acceleration. In ADAMS, kinematics and dynamics simulation on the model are made respectively. Simulation results are consistent with theoretical calculations to verify the correctness of each other, which can provide an effective basis for the control of the manipulator and the selection of the appropriate drive system. ©, 2014, Shanghai Jiao Tong University. All right reserved. (3 refs.)Main Heading: ManipulatorsControlled terms: Dynamics - Inverse kinematics - Kinematics - Lagrange multipliers - MATLAB - Robot programmingUncontrolled terms: Angular acceleration - Desired trajectories - High order polynomial - Kinematics and dynamics - Kinematics equation - Manipulator kinematics - Simulation - Theoretical calculationsClassification Code: 731.5 Robotics - 921 Mathematics - 931.1 Mechanics

Database: Compendex

Development of the large area MCP-PMT

Liu, Shulin1; Wang, Yifang1; Zhao, Tianchi1; Liu, Hulin2; Si, Shuguang3; Tian, Jinshou2; Qian, Sen1; Sun, Jian-Ning3; Cai, Xiao1; Li, Dong2; Chen, Lin2; Yan, Baojun1; Yang, Yuzhen1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9284, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413595; DOI: 10.1117/12.2069902; Article number: 928402; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Institute of High Energy Physics (IHEP) of CAS, Beijing, China2 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China3 North Night Vision Technology CO., LTD, Nanjing, China

Abstract: To adapt the specific demands of photomultiplier tubes (PMTs) in the Jiangmen Underground Neutrino Observatory, we design and manufacture a new type of micro-channel plate PMT (MCP-PMT) with the following performance indicators: the PMTs' glass shell adopts the formula of GG-17 which have no K<inf>2</inf>O, and very low background (the contents of 232Th, 238U and 40K in the raw materials are less than 40 ppb, 20 ppb and10 ppb, respectively). Its main body is sphere with 500 mm external diameter, 4 mm wall thickness and the tails that using a gradual transition of kinds of low radiation background glasses, then sealing with the Kovar. The photocathode material with lowest dark noise is bi-alkali photocathode which spectral region matches the liquid scintillator emission spectral (400&sim;440 nm). The front and back hemisphere is transmission and reflective photocathode separately. Two sets of double-stack micro-channel plates replacing the dynode chain are used to detect the photoelectrons from both sites. The focusing system makes the photoelectrons hit into the inside of MCPs to the uttermost. The anode and lead make sure charge signal is no distortion. No matter made by transfer equipment or not, the peak value of quantum efficiency of the PMT should reach 30%, and the peak-to-valley ratio of single photoelectron spectrum has surpassed 2.5:1. In a word, the MCP-PMT's reliability and other characteristics meet the need of Jiangmen Underground Neutrino Observatory. (5 refs.)Main Heading: Image storage tubesControlled terms: Elementary particles - Glass - Manufacture - Materials testing - Observatories - Optoelectronic devices - Particle beams - Photocathodes - Photoelectron spectroscopy - Photoelectrons - Photomultipliers - Photons - Quantum efficiency - Tubes (components)Uncontrolled terms: Low background - Micro channel plate - Peak-to-valley ratios - Photo multiplier tube - Single photonsClassification Code: 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 443 Meteorology - 537.1 Heat Treatment Processes - 616.1 Heat Exchange Equipment and Components - 657 Space Physics - 714.1 Electron Tubes - 714.2 Semiconductor Devices and Integrated Circuits - 812.3 Glass - 931.3 Atomic and Molecular Physics - 931.4 Quantum Theory; Quantum Mechanics - 932.1 High Energy Physics - 951 Materials Science

Database: Compendex

The design method of CGH for testing the Φ404, F2 primary mirror

Xie, Nian1, 2; Duan, Xueting1; Li, Hua1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2068031; Article number: 92800T; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an, China2 Graduate University of the Chinese Academy of Science, Beijing, China

Abstract: In order to accurately test shape quality of the large diameter aspherical mirror, a kind of binary optical element called Computer generated holograms (CGHs) are widely used.The primary role of the CGHs is to generate any desired wavefronts to realize phase compensation. In this paper, the CGH design principle and design process are reviewed at first. Then an optical testing system for testing the aspheric mirror includes a computer generated hologram (CGH) and an imaging element (IE) is disposed. And an optical testing system only concludes a CGH is proposed too. The CGH is designed for measurement of an aspheric mirror (diameter=404mm, F-number=2). Interferometric simulation test results of the aspheric mirror show that the whole test system obtains the demanded high accuracy. When combined the CGH with an imaging element in the Aspheric Compensator, the smallest feature in the CGH should be decreased. The CGH can also be used to test freeform surface with high precision, it is of great significance to the development of the freeform surface. © 2014 SPIE. (11 refs.)Main Heading: Optical testingControlled terms: Adaptive optics - Aspherics - Computer generated holography - Design - Electron holography - Holograms - Manufacture - Mirrors - Optical systems - TelescopesUncontrolled terms: Aspherical mirrors - Binary - Binary optical element - CGH - Computer generated holograms - Interferometric simulations - Optical testing system - Phase compensationClassification Code: 408 Structural Design - 537.1 Heat Treatment Processes - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 743 Holography - 743.1 Holographic Techniques - 932 High Energy Physics; Nuclear Physics; Plasma Physics

Database: Compendex

Laser spectrum detection methods for substance of Mars surface

Zhang, Dan1, 2; Xue, Bin1; Zhao, Yi-Yi1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9298, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413847; DOI: 10.1117/12.2070682; Article number: 92980F; Conference: International Symposium on Optoelectronic Technology and Application 2014: Imaging Spectroscopy; and Telescopes and Large Optics, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: The chemical element and mineral rock's abundance and distribution are the basic material of planetary geology evolution research[1], hence preterit detection for composition of Mars surface substance contains both elements sorts and mineral ingredients. This article introduced new ways to detect Mars elements and mineral components, Laser Induced Breakdown Spectroscopy (LIBS) and Raman Spectroscopy (RS) which have distinct advantages, such as work over a long distance, detect rapidly, accuratly and nondestructively. LIBS and RS both use laser excitation to shoot the substance of Mars exciting new wavelengths. The techniques of LIBS and RS in laboratory are mature, besides the technique of LIBS is being used in MSL (Chemcam) now and RS will be used in ExoMars. Comparing LIBS and RS's detection results with XRF and APXS, Mossbauer spectrometer, these existed Mars surface material detection instruments,and the Infrared spectrometer, Mid-IR, they have more accurate detection results. So LIBS and RS are competent for Mars surface substance detection instead of X-ray spectrometer and Mossbauer spectrometer which were already used in 'Viking 1' and 'Opportunity'. Only accurate detection results about Mars surface substance can lead to scientist's right analysis in inversing geological evolution of the planet. © 2014 SPIE. (12 refs.)Main Heading: MineralsControlled terms: Atomic emission spectroscopy - Chemical detection - Chemical elements - Geology - Laser excitation - Laser induced breakdown spectroscopy - Mossbauer spectroscopy - Planetary surface analysis - Spectrometers - Telescopes - X ray spectrometersUncontrolled terms: Geological evolution - Laser spectra - Laserinduced breakdown spectroscopy (LIBS) - LIBS - Mars surfaces - Mineral component - Planetary geology - RSClassification Code: 481.1 Geology - 482.2 Minerals - 657 Space Physics - 801 Chemistry - 801.4 Physical Chemistry - 804 Chemical Products Generally - 931.1 Mechanics

Database: Compendex

Dayside aurora classification via BIFs-based sparse representation using manifold learning

Han, Bing1, 2; Zhao, Xiaojing1, 2; Tao, Dacheng3; Li, Xuelong4; Hu, Zejun5; Hu, Hongqiao5 Source: International Journal of Computer Mathematics, v 91, n 11, p 2415-2426, November 2, 2014

; ISSN: 00207160, E-ISSN: 10290265; DOI: 101080/002071602013831084;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 VIPS Lab, School of Electronic Engineering, Xidian University, Xian, China2 Key Laboratory of Intelligent Perception and Image Understanding of Ministry of Education of China, Xidian University, Xian, China3 Engineering and Information Technology, University of Technology Sydney, Sydney; NSW, Australia4 Center for Optical Imagery Analysis and Learning, Xian Institute of Optics and Precision Mechanics of CAS, Xian, China5 SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai, China

Abstract: Aurora is the typical ionosphere track generated by the interaction of solar wind and magnetosphere, whose modality and variation are significant to the study of space weather activity A new aurora classification algorithm based on biologically inspired features (BIFs) and discriminative locality alignment (DLA) is proposed in this paper First, an aurora image is represented by the BIFs, which combines the C1 units from the hierarchical model of object recognition in cortex and the gist features from the saliency map; then, the manifold learning method called DLA is used to obtain the effective sparse representation for auroras based on BIFs; finally, classification results using support vector machine and nearest neighbour with three sets of features: the C1 unit features, the gist features and the BIFs illustrate the effectiveness and robustness of our method on the real aurora image database from Chinese Arctic Yellow River Station. (31 refs.)Main Heading: Classification (of information)Controlled terms: Hierarchical systems - Image retrieval - Ionosphere - Magnetosphere - Object recognition - Vector spacesUncontrolled terms: Biologically inspired - C1 unit features - Classification algorithm - Classification results - Gist features - Hierarchical model - Manifold learning - Sparse representationClassification Code: 443.1 Atmospheric Properties - 711.1 Electromagnetic Waves in Different Media - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 741 Light, Optics and Optical Devices - 921 Mathematics - 961 Systems Science

Database: Compendex

High-resolution reconstruction for terahertz imaging

Xu, Li-Min1, 2; Fan, Wen-Hui1; Liu, Jia1, 2 Source: Applied Optics, v 53, n 33, p 7891-7897, November 20, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.007891;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: We present a high-resolution (HR) reconstruction model and algorithms for terahertz imaging, taking advantage of super-resolution methodology and algorithms. The algorithms used include projection onto a convex sets approach, iterative backprojection approach, Lucy-Richardson iteration, and 2D wavelet decomposition reconstruction. Using the first two HR reconstruction methods, we successfully obtain HR terahertz images with improved definition and lower noise from four low-resolution (LR) 22 × 24 terahertz images taken from our homemade THz-TDS system at the same experimental conditions with 1.0 mm pixel. Using the last two HR reconstruction methods, we transform one relatively LR terahertz image to a HR terahertz image with decreased noise. This indicates potential application of HR reconstruction methods in terahertz imaging with pulsed and continuous wave terahertz sources. (28 refs.)Main Heading: Image reconstructionControlled terms: Algorithms - Iterative methods - Set theory - Terahertz waves - Wavelet decompositionUncontrolled terms: Continuous-wave terahertz sources - Experimental conditions - High-resolution reconstruction - Iterative back projections - Model and algorithms - Reconstruction method - Super resolution - Terahertz imagingClassification Code: 711 Electromagnetic Waves - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Integrating conventional and inverse representation for face recognition

Xu, Yong1; Li, Xuelong2; Yang, Jian3; Lai, Zhihui1; Zhang, David4 Source: IEEE Transactions on Cybernetics, v 44, n 10, p 1738-1746, October 1, 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2293391; Article number: 6684296;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Bio-Computing Research Center, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen, Guangdong, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, Shaanxi, China3 College of Computer Science and Technology, Nanjing University of Science and Technology, Nanjing, Jiangsu, China4 Biometrics Research Center, Hong Kong Polytechnic University, Hung Hom, Hong Kong

Abstract: Representation-based classification methods are all constructed on the basis of the conventional representation, which first expresses the test sample as a linear combination of the training samples and then exploits the deviation between the test sample and the expression result of every class to perform classification. However, this deviation does not always well reflect the difference between the test sample and each class. With this paper, we propose a novel representation-based classification method for face recognition. This method integrates conventional and the inverse representation-based classification for better recognizing the face. It first produces conventional representation of the test sample, i.e., uses a linear combination of the training samples to represent the test sample. Then it obtains the inverse representation, i.e., provides an approximation representation of each training sample of a subject by exploiting the test sample and training samples of the other subjects. Finally, the proposed method exploits the conventional and inverse representation to generate two kinds of scores of the test sample with respect to each class and combines them to recognize the face. The paper shows the theoretical foundation and rationale of the proposed method. Moreover, this paper for the first time shows that a basic nature of the human face, i.e., the symmetry of the face can be exploited to generate new training and test samples. As these new samples really reflect some possible appearance of the face, the use of them will enable us to obtain higher accuracy. The experiments show that the proposed conventional and inverse representation-based linear regression classification (CIRLRC), an improvement to linear regression classification (LRC), can obtain very high accuracy and greatly outperforms the naive LRC and other state-of-the-art conventional representation based face recognition methods. The accuracy of CIRLRC can be 10% greater than that of LRC. © 2013 IEEE. (53 refs.)Main Heading: Face recognitionControlled terms: Pattern recognition - SamplingUncontrolled terms: Approximation representation - Classification methods - Face recognition methods - Human faces - Linear combinations - Test samples - Theoretical foundations - Training sampleClassification Code: 716 Telecommunication; Radar, Radio and Television - 801 Chemistry

Database: Compendex

A method of small moving target detection

Li, Bin1, 2; Wen, Desheng1; Song, Zongxi1; Zhao, Bingjie1, 2; Shen, Chao1, 2; Wu, Mengjie1, 2 Source: Journal of Information and Computational Science, v 11, n 13, p 4527-4533, September 1, 2014

; ISSN: 15487741; DOI: 10.12733/jics20104353;

Publisher: Binary Information PressAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: This paper present a new method for detecting small moving targets from sequential images under the complex background of sky. The method can identify moving targets in low SNR, estimate and track the trajectory of the target using the maximum gray matrix and Kalman filter theory. Compared with other algorithms, this method has features of small amount of calculation, fast detecting speed, high real-time performance, and small identification error. Experimental results show that the pepper noise and fixed pattern noise in this type of image sequence have a good filtering effect, and also our method has good recognition and tracking effect for the small moving targets. Copyright © 2014 Binary Information Press. (9 refs.)Main Heading: Target trackingControlled terms: Image processing - Kalman filters - Signal to noise ratioUncontrolled terms: Fixed pattern noise - Identification errors - Kalman filter theory - Moving target tracking - Moving targets - Real time performance - Sequential images - Small moving target detectionsClassification Code: 716.1 Information Theory and Signal Processing - 716.2 Radar Systems and Equipment - 741 Light, Optics and Optical Devices

Database: Compendex

Influence of magnetic solenoid lens on characteristics of streak image tube

Liu, Rong1, 2, 3; Tian, Jinshou1; Wang, Qiangqiang1, 2; Wang, Chao1; Wen, Wenlong1; Lu, Yu1; Liu, Hulin1; Cao, Xibin1; Wang, Junfeng1; Zhao, Wei1 Source: Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology, v 34, n 10, p 1066-1070, October 1, 2014; Language: Chinese

; ISSN: 16727126; DOI: 10.13922/j.cnki.cjovst.2014.10.11;

Publisher: Science PressAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China3 Xi'an Technological University, Xi'an , China

Abstract: The magnetic field in the pole piece magnetic lens of a new type of femto-second (fs) streak image tube with both high temporal and spatial resolution was re-modeled to improve the precision. The influence of the magnetic solenoid lens on the magnetic field distribution and on the temporal and spatial resolution characteristics of the streak image tube was investigated. The magnetic field distributions, generated by the magnetic lens with different radius ratios, were simulated with Lorentz software; and the emission and trajectories of up to 3000 photoelectrons were sampled and calculated in Monte Carlo method with software CST PARTICLE STUDIO to statistically evaluate the temporal and spatial resolution of the image tube with the modulation transfer function. The simulated results show that the Gaussian model outperforms the bell-shaped model when it comes to description of the realistic magnetic field, and that the magnetic lens with a radius ratio of 0.83 most effectively focuses the electron beam with a temporal resolution of 190 fs and a spatial resolution over 100 lp/mm. (3 refs.)Main Heading: MagnetismControlled terms: Computer simulation - Image converters - Image resolution - Image storage tubes - Magnetic fields - Magnetic lenses - Monte Carlo methods - Solenoids - Tubes (components)Uncontrolled terms: Gaussian model - Magnetic field distribution - Simulated results - Solenoid lens - Spatial resolution - Streak image tube - Temporal and spatial - Temporal resolutionClassification Code: 616.1 Heat Exchange Equipment and Components - 701.2 Magnetism: Basic Concepts and Phenomena - 704.1 Electric Components - 714.1 Electron Tubes - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 742 Cameras and Photography - 922.2 Mathematical Statistics

Database: Compendex

Diffraction grating sampling rate measurement noise suppression technology

Wang, Wei1; Li, Dongjian1; Wang, Zhengzhou1; Xie, Zhengmao1; Cao, Shikang1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, September 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.s112005; Article number: s112005;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: The sampling rate is an important technical indicator of diffraction grating in high-energy lase device, and for the Poisson noise in the sampling rate measurement and stray light interference, the probe is inconsistent and the combination of noise processing method is proposed. The measurement environment and the statistical properties of the detector output are analyzed by statistical laws averaging methods to reduce the Poisson noise effect on the measurement results. Denoising by the histogram method, the influence of stray light is suppressed. By mutual targets, the interference caused by the inconsistencies of detector is reduced. Test results show that the sampling rate measurement relative average deviation is 0.297% and measurement standard deviation is 1.22%. The sampling rate measurement relative average deviation is better than 0.4% and measurement standard deviation is better than 2%, which meet all requirements for sampling test. The method provides a new noise suppress technical means for the measurement of the diffraction grating sampling rate and has been applied and verified in a large aperture diffraction grating comprehensive diagnosis platform. (12 refs.)Main Heading: Importance samplingControlled terms: Diffraction - Diffraction gratings - Environmental regulations - Interference suppression - Spurious signal noise - Statistics - Stray lightUncontrolled terms: Average deviation - Histogram method - Measurement standards - Sampling rates - Statistical laws - Statistical properties - Stray light suppression - Technical indicatorClassification Code: 454.2 Environmental Impact and Protection - 711 Electromagnetic Waves - 713 Electronic Circuits - 716 Telecommunication; Radar, Radio and Television - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 922 Statistical Methods - 922.2 Mathematical Statistics

Database: Compendex

Broadband high birefringence and low dispersion terahertz photonic crystal fiber

Li, Shaopeng1; Liu, Hongjun1; Huang, Nan1; Sun, Qibing1 Source: Journal of Optics (United Kingdom), v 16, n 10, October 1, 2014

; ISSN: 20408978, E-ISSN: 20408986; DOI: 10.1088/2040-8978/16/10/105102; Article number: 105102;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics Technology, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, China

Abstract: We propose a novel type of triangular lattice terahertz photonic crystal fiber with high birefringence and low dispersion in a wide spectrum range. The proposed structures have circular and elliptical air holes in the cladding. Properties of birefringence, confinement loss, and group velocity dispersion have been studied by using full-vector finite-element methods. Through adjusting the structural parameters of the photonic crystal fiber, birefringence up to 10-3 could be achieved in the frequency range of 0.1-5 THz. Moreover, group velocity dispersion curve in this frequency range is flat and the values are nearly zero. Therefore, it can be used to transmit broadband THz pulses with the polarization maintained. © 2014 IOP Publishing Ltd. (36 refs.)Main Heading: Photonic crystal fibersControlled terms: Birefringence - Crystal whiskers - Fibers - Finite element method - Group velocity dispersion - Light velocity - PolarizationUncontrolled terms: Confinement loss - Frequency ranges - Group velocity dispersion curve - High birefringence - Microstructure fibers - Structural parameter - Tera Hertz - Triangular latticeClassification Code: 711 Electromagnetic Waves - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 751 Acoustics, Noise. Sound - 801.4 Physical Chemistry - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications - 921.6 Numerical Methods - 951 Materials Science

Database: Compendex

An improved corner detection algorithm for image sequence

Yan, Minqi1; Zhang, Bianlian2; Guo, Min1; Tian, Guangyuan1; Liu, Feng1; Huo, Zeng1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9301, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413878; DOI: 10.1117/12.2071559; Article number: 93011C; Conference: International Symposium on Optoelectronic Technology and Application 2014: Image Processing and Pattern Recognition, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, 17# Information Ave., Xi'an, Shaanxi, China2 Xi'an University, 168# Taibainan Ave., Xi'an, Shaanxi, China

Abstract: A SUSAN corner detection algorithm for a sequence of images is proposed in this paper, The correlation matching algorithm is treated for the coarse positioning of the detection area, after that, SUSAN corner detection is used to obtain interesting points of the target. The SUSAN corner detection has been improved. For the situation that the points of a small area are often detected as corner points incorrectly, the neighbor direction filter is applied to reduce the rate of mistakes. Experiment results show that the algorithm enhances the anti-noise performance, improve the accuracy of detection. © 2014 SPIE. (4 refs.)Main Heading: Edge detectionControlled terms: Algorithms - Image matching - Image processing - Pattern recognition - Signal detectionUncontrolled terms: Coarse positioning - Corner detection - Correlation matching - Direction filter - Image sequence - Interesting points - Sequence of images - SUSANClassification Code: 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Research on ICCD for space observation of cosmic ray and dark matter

Hu, Bingliang1; Gao, Xiaohui1; Wang, Le2; Pi, Haifeng1; Wei, Cuiyu1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9144, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9780819496126; DOI: 10.1117/12.2055690; Article number: 91443R; Conference: Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, June 22, 2014 - June 26, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 Key Laboratory of Spectral Imaging Technology, Chinese Academy of Sciences, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: The low light level imaging and ultrafast detection system is a high performance ICCD composed of imaging intensifier and high-frame-rate CCD, the important readout system of the semi-digital 3D-imaging calorimeter for space observation of cosmic ray and dark matter that has the function of intensifying, delaying, imaging and memorizing, making rapid response to the ultrafast low light signals that is transmitted by tens of thousands of wavelength shifting fibers, generated by the semi-digital 3D-imaging calorimeter when cosmic ray is passing through. Using the images of ICCD and the semi-digital information reconstruction method, the particle type, energy and direction of cosmic ray can be obtained. By solving some key technologies such as coupling techniques of optical parts, low noise and high speed imaging of high-frame-rate and large-area CCD, the high speed gating system of imager intensifier, the prototype of high performance ICCD is developed. The prototype of ICCD can meet the requirements: up to 400 frames per second, detection ability for low light about 10 photons, linear dynamic range more than 300.Performances verification of the prototype is carried out by using a single photon test system. In this paper we will describe the requirement of ICCD for the ground cosmic detection system which is used to verify the theory of Herd (High Energy Cosmic-Radiation Detection), the key techniques used to achieve perfect performances, and test method and result of the ICCD. (8 refs.)Main Heading: Gamma raysControlled terms: Calorimeters - Cosmic rays - Cosmology - Galaxies - Gating and feeding - Imaging systems - Light - Particle beams - Photons - Space telescopesUncontrolled terms: 3D imaging - Dark matter - HERD - ICCD - Low light - Space observations - Ultra-fastClassification Code: 534.2 Foundry Practice - 657 Space Physics - 657.2 Extraterrestrial Physics and Stellar Phenomena - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 746 Imaging Techniques - 801 Chemistry - 932 High Energy Physics; Nuclear Physics; Plasma Physics - 932.1 High Energy Physics

Database: Compendex

Low-rank representation for 3D hyperspectral images analysis from map perspective

Yuan, Yuan1; Fu, Min1; Lu, Xiaoqiang1 Source: Signal Processing, March 5, 2014

; ISSN: 01651684; DOI: 10.1016/j.sigpro.2014.06.018 Article in PressAuthor affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, PR China

Abstract: Hyperspectral images naturally stand as 3D data, which carry semantic information in remote sending applications. To well utilize 3D hyperspectral images, signal processing and learning techniques have been widely exploited, and the basis is to divide a given hyperspectral data into a set of semantic classes for analysis, i.e., segmentation. To segment given hyperspectral data is an important and challenging research theme. Recently, to reduce the amount of human labor required to label samples in hyperspectral image segmentation, many approaches have been proposed and achieved good performance with a few labeled samples. However, most of them fail to exploit the high spectral correlation in distinct bands and utilize the spatial information of hyperspectral data. In order to overcome these drawbacks, a novel framework jointing the maximum a posteriori (MAP) model and low-rank representation (LRR) is proposed. In this paper, low-rank representation, conducted as a latent variables, can exploit the high spectral correlation in distinct bands and obtain a more compact and discriminative representation. On the other hand, a novel MAP framework is driven by using low-rank representation coefficient as latent variables, which will improve the probability that the closer pixels can be divided into the same class. The experiment results and quantitative analysis demonstrate that the proposed approach is effective and can obtain high segmentation accuracy compared with state-of-the-art approaches. © 2014 Elsevier B.V.Main Heading: SpectroscopyControlled terms: Independent component analysis - Semantics - Signal processingUncontrolled terms: Hyper-spectral images - Low-rank representations - Maximum a posteriori models - Segmentation accuracy - Semantic information - Spatial informations - Spectral correlation - State-of-the-art approachClassification Code: 716.1 Information Theory and Signal Processing - 723.4 Artificial Intelligence - 801 Chemistry - 903.2 Information Dissemination

Database: Compendex

Feature competition and partial sparse shape modeling for cardiac image sequences segmentation

Qin, Xianjing1, 2; Tian, Yan1; Yan, Pingkun1 Source: Neurocomputing, March 24, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2014.07.044 Article in PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, PR China2 University of Chinese Academy of Sciences, PR China

Abstract: The segmentation of endocardium and epicardium of left ventricle (LV) in cardiac MR image sequences play a crucial role in clinical applications. Active shape model (ASM) based methods are often used to extract the LV boundaries with the steps of searching and representation. However, due to the challenges, such as interior papillary muscles, complicated outside tissues and weak boundaries, the searching may be partially incorrect and the representation cannot reflect the reliable part of the contour. In this paper, a feature competition based searching strategy is proposed by exploiting both the information of the object and background to reduce the error of searching. Then, we propose a partial sparse shape model to effectively represent the searched shape. This representation is able to retain the partial reliable contour while reconstructing the unreliable part approximating to the real contour. Moreover, the incremental learning algorithm is exploited to construct a patient-specific appearance model to increase the accuracy and efficiency of image sequence segmentation. Experimental results on cardiac MR image sequences demonstrate that the proposed method improves the segmentation performance and also reduces the error accumulation compared to the existing methods. © 2014 Elsevier B.V.Main Heading: Computer visionControlled terms: Face recognition - Heart - Magnetic resonance imagingUncontrolled terms: Active shape model - Appearance modeling - Cardiac mr images - Clinical application - Error accumulation - Incremental learning - Searching strategy - Segmentation performanceClassification Code: 461.2 Biological Materials and Tissue Engineering - 716 Telecommunication; Radar, Radio and Television - 723.5 Computer Applications - 746 Imaging Techniques

Database: Compendex

Spatio-temporal Laplacian pyramid coding for action recognition

Shao, Ling1, 2; Zhen, Xiantong2; Tao, Dacheng3; Li, Xuelong4 Source: IEEE Transactions on Cybernetics, v 44, n 6, p 817-827, June 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2273174; Article number: 6572804;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom3 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology, Sydney, Ultimo, NSW 2007, Australia4 State Key Laboratory of Transient Optics and Photonics, Centre for OPTical IMagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: We present a novel descriptor, called spatio-temporal Laplacian pyramid coding (STLPC), for holistic representation of human actions. In contrast to sparse representations based on detected local interest points, STLPC regards a video sequence as a whole with spatio-temporal features directly extracted from it, which prevents the loss of information in sparse representations. Through decomposing each sequence into a set of band-pass-filtered components, the proposed pyramid model localizes features residing at different scales, and therefore is able to effectively encode the motion information of actions. To make features further invariant and resistant to distortions as well as noise, a bank of 3-D Gabor filters is applied to each level of the Laplacian pyramid, followed by max pooling within filter bands and over spatio-temporal neighborhoods. Since the convolving and pooling are performed spatio-temporally, the coding model can capture structural and motion information simultaneously and provide an informative representation of actions. The proposed method achieves superb recognition rates on the KTH, the multiview IXMAS, the challenging UCF Sports, and the newly released HMDB51 datasets. It outperforms state of the art methods showing its great potential on action recognition. © 2013 IEEE. (66 refs.)Main Heading: Laplace transformsControlled terms: Codes (symbols) - Computer vision - Image recognition - Information filtering - Motion estimationUncontrolled terms: Action recognition - Laplacian Pyramid - Max-pooling - Motion information - Sparse representation - Spatio-temporal features - State-of-the-art methods - Video sequencesClassification Code: 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 723.2 Data Processing and Image Processing - 723.5 Computer Applications - 903.1 Information Sources and Analysis - 921.3 Mathematical Transformations

Database: Compendex

Visual measurement of the pulse laser ablation process on liquid surface by using digital holography

Wang, J.1; Zhao, J.L.1; Di, J.L.1; Rauf, A.1; Yang, W.Z.2; Wang, X.L.2 Source: Journal of Applied Physics, v 115, n 17, May 7, 2014

; ISSN: 00218979, E-ISSN: 10897550; DOI: 10.1063/1.4874742; Article number: 173106;

Publisher: American Institute of Physics Inc.Author affiliation: 1 Key Laboratory of Space Applied Physics and Chemistry, Ministry of Education, Northwestern Polytechnical University, Xi'an 710072, China2 State Key Laboratory of Transient Optics and Photonics Technology, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We present a visual method to dynamically and quantitatively measure the ablation process on liquid surface induced by pulse laser based on digital holography. Taking deionized water as a liquid example, the quantitative data of the evolution of cavity, jet, and pressure in ablation process are experimentally obtained. According to Abel inversion, the refractive index and the thickness contained in the phase information of the axisymmetric jet are decoupled. The temporal resolution, temporal stability, and measurement accuracy of this method are analyzed based on digital holographic theory. In addition, a numerical simulation is performed to calculate the maximum cavity depth, and the results are in good agreement with the experimental data. © 2014 AIP Publishing LLC. (25 refs.)Main Heading: LiquidsControlled terms: Ablation - Computer generated holography - Deionized water - Refractive indexUncontrolled terms: Digital holography - Holographic theory - Maximum cavity depths - Measurement accuracy - Phase information - Temporal resolution - Temporal stability - Visual measurementsClassification Code: 445.1 Water Treatment Techniques - 641.2 Heat Transfer - 723.5 Computer Applications - 741.1 Light/Optics - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

High-precision method of machining taper holes of diesel engine nozzle with femtosecond laser

Wang, Feng1, 2; Luo, Jian-Jun1; Li, Ming2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 4, April 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144304.0414003; Article number: 0414003;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Femtosecond laser processing has litle-thermal effects, high precision, and is not particular about materials. Aiming at the machining requirement for nozzle's spray holes, as a key part of the high pressure common rail injection system for diesel engine, a femtosecond laser processing apparatus with three-wedge scanning system was designed for technical research of taper holes' machining. Then tests of the taper holes' physical dimensions and the flow rate of the fuel jet nozzles were carried out with three coordinates measuring machine (measurement accuracy 1.2 μm) and high-pressure liquid flow test bench for the injector(measurement accuracy ±0.1%). The experimental results show that the designed apparatus can machine nozzles, and the performance is able to meet the application requirement of Euro V emission regulations. The technique has important significance for improving the level of automobile industry and domestic emission standard of diesel engined car. (15 refs.)Main Heading: Diesel enginesControlled terms: Automotive industry - Flow rate - Micromachining - Nozzles - Spray nozzles - Ultrashort pulsesUncontrolled terms: Application requirements - Emission regulation - Femtosecond laser processing - High pressure common rail - High pressure common rail injection system - High-pressure liquid - Measurement accuracy - Taper holesClassification Code: 604.2 Machining Operations - 612.2 Diesel Engines - 631 Fluid Flow - 631.1 Fluid Flow, General - 661 Automotive Engines and Related Equipment - 662 Automobiles and Smaller Vehicles - 663 Buses, Tractors and Trucks - 664 Automotive Engineering, General - 744.1 Lasers, General

Database: Compendex

A nonlinear adaptive level set for image segmentation

Wang, Bin1; Gao, Xinbo1; Tao, Dacheng2; Li, Xuelong3 Source: IEEE Transactions on Cybernetics, v 44, n 3, p 418-428, March 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2256891; Article number: 6542718;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic Engineering, Xidian University, Xi'an 710071, Shaanxi, China2 Centre for Quantum Computation and Intelligent Systems, University of Technology, Sydney, Ultimo, NSW 2007, Australia3 State Key Laboratory of Transient Optics and Photonics, Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, Shaanxi, China

Abstract: In this paper, we present a novel level set method (LSM) for image segmentation. By utilizing the Bayesian rule, we design a nonlinear adaptive velocity and a probability-weighted stopping force to implement a robust segmentation for objects with weak boundaries. The proposed method is featured by the following three properties: 1) it automatically determines the curve to shrink or expand by utilizing the Bayesian rule to involve the regional features of images; 2) it drives the curve evolve with an appropriate speed to avoid the leakage at weak boundaries; and 3) it reduces the influence of false boundaries, i.e., edges far away from objects of interest. We applied the proposed segmentation method to artificial images, medical images and the BSD-300 image dataset for qualitative and quantitative evaluations. The comparison results show the proposed method performs competitively, compared with the LSM and its representative variants. © 2013 IEEE. (40 refs.)Main Heading: Image segmentationControlled terms: Finite difference method - Partial differential equationsUncontrolled terms: Active contours - Bayesian criterion - Comparison result - Level Set - Level Set method - Quantitative evaluation - Robust segmentation - Segmentation methodsClassification Code: 741.1 Light/Optics - 921.2 Calculus - 921.6 Numerical Methods

Database: Compendex

Phase retrieval using spatially modulated illumination

Gao, Peng1, 2; Pedrini, Giancarlo1; Zuo, Chao1, 3; Osten, Wolfgang1 Source: Optics Letters, v 39, n 12, p 3616-3618, June 15, 2014

; ISSN: 01469592, E-ISSN: 15394794; DOI: 10.1364/OL.39.003615;

Publisher: Optical Society of American (OSA)Author affiliation: 1 Institut für Technische Optik, Universität Stuttgart, Pfaffenwaldring 9, 70569 Stuttgart, Germany2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Centre for Optical and Laser Engineering, School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore

Abstract: In this Letter, we propose a method for retrieving the phase of a wavefront from the diffraction patterns recorded when the object is sequentially illuminated by spatially modulated light. For wavefronts having a smooth phase, the retrieval is achieved by using a deterministic method. When the phase has discontinuities, an iterative process is used for the retrieval and enhancement of the spatial resolution. Both the deterministic and iterative phase reconstructions are demonstrated by experiments. © 2014 Optical Society of America. (31 refs.)Main Heading: Iterative methodsControlled terms: Optical microscopy - WavefrontsUncontrolled terms: Deterministic methods - Iterative process - Phase reconstruction - Phase retrieval - Spatial resolution - Spatially modulated - Spatially modulated illuminationClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 921.6 Numerical Methods

Database: Compendex

The compensation of Y waveguide temperature drifts in FOG with the thermal resistor

Wang, Ying Li1; Ren, Li Yong1; Xu, Jin Tao1, 2; Liang, Jian1; Kang, Meng Hua1, 3; Ren, Kai Li1, 3; Shi, Nian Bao1, 2 Source: Advanced Materials Research, v 924, p 336-342, 2014, Frontiers in Micro-Nano Science and Technology

; ISSN: 10226680; ISBN-13: 9783038350569; DOI: 10.4028/www.scientific.net/AMR.924.336; Conference: 12th China International Nanoscience and Technology Symposium, and the Nano-Products Exposition, CINSTS 2013, October 27, 2013 - October 31, 2013; Sponsor: Chinese Society of MironanoTechnology; IEEE Nanotechnology Council;

Publisher: Trans Tech PublicationsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China2 Xi'an Sino Huaxin Measurement and Control Co., Ltd, Xi'an, 710119, China3 University of Chinese Academy of Sciences, Beijing, 100049, China

Abstract: The lithium niobate integrated optical phase modulator(Y waveguide) is the key device in the digital closed-loop fiber optic gyroscope. However, the half-wave voltage of the lithium niobate changes with the environment temperature, which produces the phase bias drift and ultimately decreases the accuracy of FOG. In this manuscript, the thermal resistor is introduced in the amplification part in the driving circuits of Y waveguide. Due to the characteristic of the thermal resistor, the magnitude of driving voltage on Y waveguide changed with temperature to compensate the electro-optic effect's temperature drift of the lithium niobate. This method was proved to improve the performance of fiber optic gyroscopes conveniently in experiment. © (2014) Trans Tech Publications, Switzerland. (11 refs.)Main Heading: Fiber opticsControlled terms: Gyroscopes - Thermistors - WaveguidesUncontrolled terms: Compensation circuits - Electrooptic effects - Environment temperature - Fiber optic gyroscopes - Half-wave voltage - Optical phase modulator - Temperature drifts - Thermal resistorClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 741.1.2 Fiber Optics - 943.1 Mechanical Instruments

Database: Compendex

Tunneling induced dark states and the controllable resonance fluorescence spectrum in quantum dot molecules

Tian, Si-Cong1; Wan, Ren-Gang2; Tong, Cun-Zhu1; Ning, Yong-Qiang1; Qin, Li1; Liu, Yun1 Source: Journal of Physics B: Atomic, Molecular and Optical Physics, v 47, n 15, August 14, 2014

; ISSN: 09534075, E-ISSN: 13616455; DOI: 10.1088/0953-4075/47/15/155503; Article number: 155503;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Optical spectroscopy, a powerful tool for probing and manipulating quantum dots (QDs), has been used to investigate the resonance fluorescence spectrum from linear triple quantum dot molecules controlled by tunneling, using atomic physics methods. Interesting features such as quenching and narrowing of the fluorescence are observed. In such molecules the tunneling between the quantum dots can also induce a dark state. The results are explained by the transition properties of the dressed states generated by the coupling of the laser and the tunneling. Unlike the atomic system, in such quantum dot molecules quantum coherence can be induced using tunneling, requiring no coupling lasers, which will allow tunneling controllable quantum dot molecules to be applied to quantum optics and photonics. © 2014 IOP Publishing Ltd. (51 refs.)Main Heading: Semiconductor quantum dotsControlled terms: Atomic physics - Electron tunneling - Fluorescence - Molecules - Quantum optics - Quantum theory - ResonanceUncontrolled terms: Dark state - Optical spectroscopy - Physics methods - Quantum coherence - Quantum dot molecules - Resonance fluorescence spectrum - Resonance fluorescences - Transition propertiesClassification Code: 701 Electricity and Magnetism - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 931.3 Atomic and Molecular Physics - 931.4 Quantum Theory; Quantum Mechanics

Database: Compendex

Adaptive fusion of particle filtering and spatio-temporal motion energy for human tracking

Zhou, Huiyu1; Fei, Minrui2; Sadka, Abdul3; Zhang, Yi4; Li, Xuelong5 Source: Pattern Recognition, v 47, n 11, p 3552-3567, November 2014

; ISSN: 00313203; DOI: 10.1016/j.patcog.2014.05.006;

Publisher: Elsevier LtdAuthor affiliation: 1 School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Belfast BT3 9DT, United Kingdom2 School of Mechatronics Engineering and Automation, Shanghai University, China3 School of Engineering and Design, Brunel University, United Kingdom4 Institute of Automation, Chongqing University of Post and Telecommunication, China5 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Object tracking is an active research area nowadays due to its importance in human computer interface, teleconferencing and video surveillance. However, reliable tracking of objects in the presence of occlusions, pose and illumination changes is still a challenging topic. In this paper, we introduce a novel tracking approach that fuses two cues namely colour and spatio-temporal motion energy within a particle filter based framework. We conduct a measure of coherent motion over two image frames, which reveals the spatio-temporal dynamics of the target. At the same time, the importance of both colour and motion energy cues is determined in the stage of reliability evaluation. This determination helps maintain the performance of the tracking system against abrupt appearance changes. Experimental results demonstrate that the proposed method outperforms the other state of the art techniques in the used test datasets. © 2014 Elsevier Ltd. (67 refs.)Main Heading: Image processingControlled terms: Color - Computer vision - Human computer interaction - Monte Carlo methods - Security systems - Signal filtering and prediction - Tracking (position)Uncontrolled terms: Human computer interfaces - Illumination changes - Motion energy - Object Tracking - Occlusion - Reliability Evaluation - Spatio-temporal dynamics - State-of-the-art techniquesClassification Code: 461.4 Ergonomics and Human Factors Engineering - 716.2 Radar Systems and Equipment - 731.1 Control Systems - 741 Light, Optics and Optical Devices - 914.1 Accidents and Accident Prevention - 922.2 Mathematical Statistics

Database: Compendex

Phase control of light amplification in steady and transient processes in an inverted-Y atomic system with spontaneously generated coherence

Tian, Si-Cong1; Tong, Cun-Zhu1; Wan, Ren-Gang3; Ning, Yong-Qiang1; Qin, Li1; Liu, Yun1; Wang, Li-Jun1; Zhang, Hang1; Wang, Zeng-Bin4; Gao, Jin-Yue2 Source: Chinese Physics B, v 23, n 4, April 2014

; ISSN: 16741056; DOI: 10.1088/1674-1056/23/4/044205; Article number: 044205;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Luminescence and Application, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China2 State Key Lab. of Coherent Light and Atomic and Molecular Spectroscopy of Ministry of Education, College of Physics, Jilin University, Changchun 130012, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China4 Quantum Engineering Center, Beijng Institute of Control Devices, Beijing 100854, China

Abstract: We investigate the effects of spontaneously generated coherence (SGC) on both the steady and transient gain properties in a four-level inverted-Y-type atomic system in the presence of a weak probe, two strong coherent fields, and an incoherent pump. For the steady process, we find that the inversionless gain mainly origins from SGC. In particular, we can modulate the inversionless gain by changing the relative phase between the two fields. Moreover, the amplitude of the gain peak can be enhanced and the additional gain peak can appear by changing the detuning of the coupling field. As for the transient process, the transient gain properties can also be dramatically affected by the SGC. Compared to the case without SGC, the transient gain can be greatly enhanced with completely eliminated transient absorption by choosing the proper relative phase between the two fields. And the inverted-Y-type system with SGC can be simulated in both atomic and semiconductor quantum well systems avoiding the conditions of SGC. © 2014 Chinese Physical Society and IOP Publishing Ltd. (54 refs.)Main Heading: AmplificationControlled terms: Atoms - Semiconductor quantum wells - Spontaneous emission - Transmission line theoryUncontrolled terms: Gain without inversion - Light amplification - Relative phase - Spontaneously generated coherence - Steady and transient - Transient absorption - Transient evolution - Transient processClassification Code: 703.1 Electric Networks - 711 Electromagnetic Waves - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 931.3 Atomic and Molecular Physics

Database: Compendex

Accelerating beams with non-parabolic trajectories

Yan, Shaohui1; Li, Manman1, 2; Yao, Baoli1; Lei, Ming1; Yu, Xianghua1, 2; Qian, Jia1, 2; Gao, Peng1 Source: Journal of Optics (United Kingdom), v 16, n 3, March 2014

; ISSN: 20408978, E-ISSN: 20408986; DOI: 10.1088/2040-8978/16/3/035706; Article number: 035706;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: We present a family of one-dimensional accelerating beams in the paraxial limit whose trajectory is described, in normalized coordinates (ξ, s), by a non-parabolic curve ξ = α(s) with α(s) denoting the transverse shift of beams. When taking different values of the parameters appearing in α(s), three types of accelerating beams are observed. The first type accelerates initially along X direction and almost stops accelerating after traveling a large distance. The second type is seen to travel along a straight line with an angle with respect to the Z-axis at large distance. The beam of the last type is seen to leave initially upward and cross the Z-axis downward after traveling some distance. © 2014 IOP Publishing Ltd. (14 refs.)Main Heading: OpticsUncontrolled terms: accelerating beams - nonparabolic curve - Paraxial limits - Transverse shiftClassification Code: 741.1 Light/Optics

Database: Compendex

The progress of sub-pixel imaging methods

Wang, Hu1, 2; Wen, Desheng1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9142, 2014, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410938; DOI: 10.1117/12.2054205; Article number: 91420K; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013, October 20, 2013 - October 29, 2013; Sponsor: Chinese Society of Astronautics; ducation, Shanghai Jiaotong University; Education and Training Department, China; Key Laboratory for Laser Plasmas, Ministry of E; Ordnance Society; Photoelectronic Technology Professional Committee,;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanism, Chinese Academy of Sciences, Xi'an, 710019, China2 School of Astronautics, Northwestern Polytechnical University, Xi'an, 710072, China

Abstract: This paper reviews the Sub-pixel imaging technology principles, characteristics, the current development status at home and abroad and the latest research developments. As Sub-pixel imaging technology has achieved the advantages of high resolution of optical remote sensor, flexible working ways and being miniaturized with no moving parts. The imaging system is suitable for the application of space remote sensor. Its application prospect is very extensive. It is quite possible to be the research development direction of future space optical remote sensing technology. © 2014 Copyright SPIE. (7 refs.)Main Heading: Remote sensingControlled terms: Image reconstruction - Imaging techniques - Optical image storage - Space optics - TechnologyUncontrolled terms: Development status - High-resolution imaging - Imaging technology - Optical remote sensing - Optical remote sensors - Research development - Space remote sensors - Sub pixelsClassification Code: 731.1 Control Systems - 741 Light, Optics and Optical Devices - 746 Imaging Techniques - 901 Engineering Profession

Database: Compendex

Measurement of extinction ratio by dual modulation

Li, Chun-Yan1, 2; Wu, Yi-Ming1; Gao, Li-Min1; Lu, Wei-Guo1; Xiao, Mao-Sen1 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 3, p 582-587, March 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142203.0582;

Abstract: A method by using magneto-optical modulation and light source modulation techniques was proposed to measure the extinction ratio of a polarizing prism precisely, and an extinction ratio measurement system was also established based on the two modulation techniques. Firstly, the system's measurement model was derived according to the Jones matrix describing manner of polarized light. By using a magneto-optical modulator, the optical axis angle between a polarizer and a measured polarizing prism was precisely located. Then, by using a chopper to modulate the square wave of a light source, the impact of noises on the system measurement accuracy was eliminated and the system could measure the light intensity value accurately after the measured polarizing prism's axis was located precisely. Finally, the polarizing prism was measured for a number of times and the data were averaged. The experimental results indicate that the measurement accuracy of extinction ratio for the polarizing prism can be 10-6, which verifies the effectiveness and stability of the method. The system is characterized by high stability, high accuracy, and can offer the references for the performance test and engineering applications of polarized devices. (10 refs.)Main Heading: PolarizationControlled terms: Frequency modulation - Light extinction - Light modulation - Light modulators - Light polarization - Light sources - PrismsUncontrolled terms: Engineering applications - Extinction ratio measurements - Extinction ratios - Magneto-optical - Magneto-optical modulators - Modulation techniques - Polarizing prisms - Source modulationClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Effect of Gb on phase transformation and martensitic phase transformation in Ni-Mn-In alloys

Cheng, Ya Dong1, 2 Source: Advanced Materials Research, v 1015, p 177-180, 2014, Chemical Engineering and Material Properties III

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038352303; DOI: 10.4028/www.scientific.net/AMR.1015.177; Conference: 4th International Symposium on Chemical Engineering and Material Properties, ISCEMP 2014, June 28, 2014 - June 29, 2014; Sponsor: Cross Ref; Engineering Village; et al; INTIEA - Informatization and Engineering; Scientific.Net; Trans Tech Publications inc;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 University of Chinese Academy of Sciences, Beijing 100049, China2 Xi'an Institute of Optics and Fine Mechanics, Xi'an, 710119, China

Abstract: The Ni-Mn-In alloy occur martensite reverse phase transitions driven by magnetic field in a certain composition range, resulting in the macroscopic strain, and along with the output of up to 108 MPa stress. However, there are some defects impeded practical application of alloy, such as brittleness and low Curie temperature. So, we will improve its mechanical properties by doping the suitable rare earth Gd elements in Ni-Mn-In alloy in this paper.In this paper, we study the microstructure, martensitic transformation and mechanical properties of Ni<inf>45.4</inf>Mn4<inf>1.5-x</inf>In<inf>13.1</inf>Gd<inf>x</inf> (x=0,0.2,0.5,1,2)magnetic shape memory alloy by DSC and Compression fracture strength and strain curve, which clarify the influence of Gd doping on martensitic phase transformation and mechanical properties of alloys.The studies have shown that the microstructure of the alloy changes from single organization into a mixed-phase structure of the matrix and the rich-Gd phase with the increasing of rare earth Gd content and martensitic transformation temperature of the alloys increases gradually with the increasing of Gd element content; The fracture strength and fracture strain increases first and then a decreasing trend with increasing the rare earth Gd elements. The result of the improved mechanical properties is the co-action of fine grain strengthening and second phase strengthening. © (2014) Trans Tech Publications, Switzerland. (5 refs.)Main Heading: GadoliniumControlled terms: Alloys - Fracture mechanics - Fracture toughness - Manganese - Martensitic transformations - Mechanical properties - Microstructure - Nickel - Phase structure - Rare earths - Shape memory effect - StrainUncontrolled terms: Compression fracture - Fine grain strengthening - Low Curie temperature - Macroscopic strains - Magnetic shape memory alloys - Martensitic phase transformations - Martensitic transformation temperatures - Second phase strengtheningClassification Code: 421 Strength of Building Materials; Mechanical Properties - 481.2 Geochemistry - 531.1 Metallurgy - 531.2 Metallography - 543.2 Manganese and Alloys - 547.2 Rare Earth Metals - 548.1 Nickel - 933 Solid State Physics - 951 Materials Science

Database: Compendex

Toward a biometric-aware cloud service engine for multi-screen video applications

Hu, Han1; Jin, Yichao2; Wen, Yonggang2; Chua, Tat-Seng1; Li, Xuelong3 Source: SIGCOMM 2014 - Proceedings of the 2014 ACM Conference on Special Interest Group on Data Communication, p 581-582, 2014, SIGCOMM 2014 - Proceedings of the 2014 ACM Conference on Special Interest Group on Data Communication; ISBN-13: 9781450328364; DOI: 10.1145/2619239.2631430; Conference: 2014 ACM Conference on Special Interest Group on Data Communication, SIGCOMM 2014, August 17, 2014 - August 22, 2014; Sponsor: ACM SIGCOMM;

Publisher: Association for Computing MachineryAuthor affiliation: 1 School of Computing, National Univ. of Singapore, Singapore 117417, Singapore2 School of Computer Eng., Nanyang Tech. University, Singapore 639798, Singapore3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), XIOPM, CAS, Xi'an 710119, China

Abstract: The emergence of portable devices and online social networks (OSNs) has changed the traditional video consumption paradigm by simultaneously providing multi-screen video watching, social networking engagement, etc. One challenge is to design a unified solution to support ever-growing features while guarantee system performance. In this demo, we design and implement a multi-screen technology to provide multi-screen interactions over wide area network (WAN). Furthermore, we incorporate face-detection technology into our system to identify users' bio-features and employ a machine learning based traffic scheduling mechanism to improve the system performance. © 2014 Authors. (3 refs.)Main Heading: BiometricsControlled terms: Artificial intelligence - Clouds - Convolutional codes - Scheduling - Social networking (online) - Wide area networksUncontrolled terms: Design and implements - Internet video - Online social networks (OSNs) - Portable device - Second screens - Traffic scheduling - Unified solutions - Video applicationsClassification Code: 443 Meteorology - 722.3 Data Communication, Equipment and Techniques - 723 Computer Software, Data Handling and Applications - 912.2 Management

Database: Compendex

Laboratory simulation of atmosphere turbulence for Fourier telescopy

Zeng, Zhi-Hong1, 2; Luo, Xiu-Juan1; Wang, Bao-Feng1, 2; Xia, Ai-Li1; Cheng, Zhi-Yuan1, 2; Si, Qing-Dan1, 2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 6, June 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144306.0601002; Article number: 0601002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences (CAS), Xi'an 710119, China2 Graduate University of CAS, Beijing 100049, China

Abstract: Fourier telescopy is a sort of high-resolution imaging technology for deep space object which is very small and dim. To verify the atmosphere turbulence net effect on Fourier telescope, the experimental demonstrations of atmosphere turbulence simulation were performed in a lab. Based on the laboratory system of three-beam Fourier telescope, the scintillation and the phase jitter were simulated by changing the radio-frequency driver output power and the instantaneous frequency, respectively. The detail of the experimental principle was presented, and the relation between the turbulent intensity and experimental variable was built. For different cases with random scintillation and phase jitter in weak turbulence, the experiments were conducted for single beam and three beams, and all the results' Strehl ratio were calculated. The experimental results indicate that, with single beam holding turbulence, there are no obvious change for all the reconstructed image; with three beams adding turbulence, the image quality of the Fourier telescope system is few influenced by weak scintillation, but is severe affected by phase jitter. As indicated, removing the phase and light intensity jitter effect is a key point of improving the image reconstruction arithmetic. (17 refs.)Main Heading: Atmospheric turbulenceControlled terms: Fourier transforms - Image reconstruction - Imaging systems - Jitter - Scintillation - TelescopesUncontrolled terms: Atmosphere turbulence - Experimental demonstrations - Fourier telescopy - High-resolution imaging - Instantaneous frequency - Laboratory simulation - Turbulence simulation - Turbulent intensitiesClassification Code: 443.1 Atmospheric Properties - 657 Space Physics - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 746 Imaging Techniques - 921.3 Mathematical Transformations

Database: Compendex

Algorithm of laser spot detection based on optimal arc

Cao, Shikang1; Li, Dongjian1; Xu, Ruihua1; Wang, Wei1; Wang, Zhengzhou1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 10, p 3492-3496, October 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China

Abstract: Laser spot detection is the key technique used in optical measurement, and widely used in optical measurement system, optical automatic alignment system and laser communication target tracing. In order to improve the optical measurement and anti-interference of spot center and radius, a kind of laser spot center detecting algorithm was put forward based on the optimal arc, according to the symmetry of a circle, the algorithm overcame the interference edges, and then selected the arc with good sysmmetry as the optimal arc to provid the fitting data, calculated center and radius of a circle by using the least squraes method. And it was compared with other commonly used algorithms. Experiments show that the proposed algorithm has high orientation precision for the center and radius, fast speed, and can improve the anti-interference of testing center. The algorithm is suitable for real-time detection. (10 refs.)Main Heading: AlgorithmsControlled terms: Image processing - Least squares approximations - Optical communication - Optical data processing - Optical variables measurementUncontrolled terms: Automatic alignment - Circle fitting - Laser spots - Least square methods - Optical measurement - Optical measurement systems - Optimal arc - Real-time detectionClassification Code: 717.1 Optical Communication Systems - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921 Mathematics - 921.6 Numerical Methods - 941.4 Optical Variables Measurements

Database: Compendex

Misalignment induced aberration characteristic of Cassegrain telescope

Pang, Zhihai1, 2; Fan, Xuewu1; Ma, Zhen1; Chen, Qinfang1; Zou, Gangyi1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 195-200, January 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Based on the vector wavefront aberration theory, the misalignment induced aberration' s characteristic of Cassegrain optical system was analyzed in this paper. It is shown that a misaligned Cassegrain has three residual 3rd aberrations. The 3rd order spherical aberration is constant over the field and the 3rd order coma increases linearly with the field but the zero coma point no longer locates at the field center. Moreover, the astigmatism aberration field in system without symmetric contains two zero astigmatism point, neither of which is necessarily located on the field center of view. It has been demonstrated that a Cassegrain under assembly is only measured to have perfect performance on-axis but not aligned in any significant way, so the measurements of multiple field points for the Cassegrain are required in the process of alignment. (12 refs.)Main Heading: Optical systemsControlled terms: Aberrations - AlignmentUncontrolled terms: Cassegrain - Cassegrain telescopes - Field points - Measurements of - Misalignment - Optical assemblies - Spherical aberrations - Wavefront aberrationsClassification Code: 601.1 Mechanical Devices - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems

Database: Compendex

Spectral-spatial constraint hyperspectral image classification

Ji, Rongrong1; Gao, Yue2; Hong, Richang3; Liu, Qiong4; Tao, Dacheng5; Li, Xuelong6 Source: IEEE Transactions on Geoscience and Remote Sensing, v 52, n 3, p 1811-1824, March 2014

; ISSN: 01962892; DOI: 10.1109/TGRS.2013.2255297; Article number: 6527932;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Department of Cognitive Science, School of Information Science and Technology, Xiamen University, Xiamen 361005, China2 School of Computing, National University of Singapore, Singapore 117417, Singapore3 Computer Science and Information Engineering, Hefei University of Technology, Hefei Hefei 230009, China4 Department of Electronic and Information Engineering, Huazhong University of Science and Technology, Wuhan, China5 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology, Sydney 2007, Australia6 State Key Laboratory of Transient Optics and Photonics, Xiàn Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xiàn 710119, China

Abstract: Hyperspectral image classification has attracted extensive research efforts in the recent decade. The main difficulty lies in the few labeled samples versus the high dimensional features. To this end, it is a fundamental step to explore the relationship among different pixels in hyperspectral image classification, toward jointly handing both the lack of label and high dimensionality problems. In the hyperspectral images, the classification task can be benefited from the spatial layout information. In this paper, we propose a hyperspectral image classification method to address both the pixel spectral and spatial constraints, in which the relationship among pixels is formulated in a hypergraph structure. In the constructed hypergraph, each vertex denotes a pixel in the hyperspectral image. And the hyperedges are constructed from both the distance between pixels in the feature space and the spatial locations of pixels. More specifically, a feature-based hyperedge is generated by using distance among pixels, where each pixel is connected with its K nearest neighbors in the feature space. Second, a spatial-based hyperedge is generated to model the layout among pixels by linking where each pixel is linked with its spatial local neighbors. Both the learning on the combinational hypergraph is conducted by jointly investigating the image feature and the spatial layout of pixels to seek their joint optimal partitions. Experiments on four data sets are performed to evaluate the effectiveness and and efficiency of the proposed method. Comparisons to the state-of-the-art methods demonstrate the superiority of the proposed method in the hyperspectral image classification. © 2013 IEEE. (46 refs.)Main Heading: Image classificationControlled terms: Independent component analysis - Pixels - SpectroscopyUncontrolled terms: Classification tasks - High dimensional feature - Hyper-spectral images - Hypergraph - HyperSpectral - Hyperspectral image classification - spatial-constraint - State-of-the-art methodsClassification Code: 716 Telecommunication; Radar, Radio and Television - 723.4 Artificial Intelligence - 723.5 Computer Applications - 801 Chemistry

Database: Compendex

Spectral-spatial constraint hyperspectral image classification

Ji, Rongrong1; Gao, Yue2; Hong, Richang3; Liu, Qiong4; Tao, Dacheng5; Li, Xuelong6 Source: IEEE Transactions on Geoscience and Remote Sensing, v 52, n 3, p 1811-1824, March 2014

; ISSN: 01962892; DOI: 10.1109/TGRS.2013.2255297; Article number: 6527932;

Abstract: Hyperspectral image classification has attracted extensive research efforts in the recent decade. The main difficulty lies in the few labeled samples versus the high dimensional features. To this end, it is a fundamental step to explore the relationship among different pixels in hyperspectral image classification, toward jointly handing both the lack of label and high dimensionality problems. In the hyperspectral images, the classification task can be benefited from the spatial layout information. In this paper, we propose a hyperspectral image classification method to address both the pixel spectral and spatial constraints, in which the relationship among pixels is formulated in a hypergraph structure. In the constructed hypergraph, each vertex denotes a pixel in the hyperspectral image. And the hyperedges are constructed from both the distance between pixels in the feature space and the spatial locations of pixels. More specifically, a feature-based hyperedge is generated by using distance among pixels, where each pixel is connected with its K nearest neighbors in the feature space. Second, a spatial-based hyperedge is generated to model the layout among pixels by linking where each pixel is linked with its spatial local neighbors. Both the learning on the combinational hypergraph is conducted by jointly investigating the image feature and the spatial layout of pixels to seek their joint optimal partitions. Experiments on four data sets are performed to evaluate the effectiveness and and efficiency of the proposed method. Comparisons to the state-of-the-art methods demonstrate the superiority of the proposed method in the hyperspectral image classification. © 2013 IEEE. (46 refs.)Controlled terms: data set - image classification - learning - pixel - research - spectral resolutionClassification Code: 71.8.5.4 Remote sensing: numerical and image analysis

Database: GEOBASE

Robust superpixel tracking via depth fusion

Yuan, Yuan1; Fang, Jianwu1; Wang, Qi1 Source: IEEE Transactions on Circuits and Systems for Video Technology, v 24, n 1, p 15-26, January 2014

; ISSN: 10518215; DOI: 10.1109/TCSVT.2013.2273631; Article number: 6560405;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Center for OPTical IMagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China

Abstract: Although numerous trackers have been designed to adapt to the nonstationary image streams that change over time, it remains a challenging task to facilitate a tracker to accurately distinguish the target from the background in every frame. This paper proposes a robust superpixel-based tracker via depth fusion, which exploits the adequate structural information and great flexibility of mid-level features captured by superpixels, as well as the depth-map's discriminative ability for the target and background separation. By introducing graph-regularized sparse coding into the appearance model, the local geometrical structure of data is considered, and the resulting appearance model has a more powerful discriminative ability. Meanwhile, the similarity of the target superpixels' neighborhoods in two adjacent frames is also incorporated into the refinement of the target estimation, which helps a more accurate localization. Most importantly, the depth cue is fused into the superpixel-based target estimation so as to tackle the cluttered background with similar appearance to the target. To evaluate the effectiveness of the proposed tracker, four video sequences of different challenging situations are contributed by the authors. The comparison results demonstrate that the proposed tracker has more robust and accurate performance than seven ones representing the state-of-the-art. © 2013 IEEE. (45 refs.)Main Heading: Graph theoryControlled terms: Computer vision - Image processing - Image segmentationUncontrolled terms: Cluttered backgrounds - Discriminative ability - Geometrical structure - Object Tracking - Sparse coding - Structural information - Super pixels - Target and backgroundClassification Code: 741 Light, Optics and Optical Devices - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Nonlinear characterization on mid-infrared fluorotellurite glass fiber

Zhan, Huan1, 2, 3; Shi, Tengfei1, 3; Zhang, Aidong1; Zhou, Zhiguang1; Si, Jinhai2; Lin, Aoxiang1 Source: Materials Letters, v 120, p 174-176, April 1, 2014

; ISSN: 0167577X; DOI: 10.1016/j.matlet.2014.01.071;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an 710119, China2 Key Laboratory for Physical Electronics and Devices, Ministry of Education and Shaanxi Key Lab of Information Photonic Technique, Xi'An Jiaotong University, Xianning-xilu 28, Xi'an 710049, China3 Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049, China

Abstract: By physical and chemical dehydration technique to remove OH group from raw materials and via built-in casting method to make glass fiber preform, mid-infrared fluorotellurite glass fibers with low loss of 3.61 dB/m at 1550 nm were fabricated recently. With the addition of fluoride components, fluorotellurite glass fiber cane presents a 'water-free' state with a broadband transparency in the range of 0.38-4.2 μm. By the continuous-wave self-phase modulation method, the nonlinear refractive index n<inf>2</inf> and the effective nonlinear parameter γ of the made fluorotellurite glass fiber were estimated to be 1.4×10-18 m2/W and 20.9/W/km at 1550 nm, respectively. © 2013 Elsevier B.V. All rights reserved. © 2014 Elsevier B.V. (19 refs.)Main Heading: FibersControlled terms: Glass fibers - Infrared devices - Oxidation - Refractive indexUncontrolled terms: Casting method - Continuous waves - Fibre technology - Fluoro-tellurite glass - FTIR - Non-linear parameters - Nonlinear characterization - Nonlinear refractive indexClassification Code: 413 Insulating Materials - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 802.2 Chemical Reactions - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

Near- and mid-infrared emissions of Dy3+ doped and Dy 3+/Tm3+co-doped lead cesium iodide modified chalcohalide glasses

Guo, Haitao1; Xu, Yantao1; Chen, Hongyan2; He, Xin3; Cui, Xiaoxia1; Wang, Pengfei1; Lu, Min1; Li, Weinan1; Hou, Chaoqi1; Peng, Bo1 Source: Journal of Luminescence, v 148, p 10-17, April 1, 2014

; ISSN: 00222313; DOI: 10.1016/j.jlumin.2013.11.011;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, Shaanxi 710119, China2 Institute of Publication Science, Chang'An University, Xi'an, Shaanxi 710064, China3 School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong 529020, China

Abstract: 0.2 wt% Dy3+ doped and 0.2 wt% Dy3+/0.5 wt% Tm 3+ co-doped novel GeS<inf>2</inf>-Ga<inf>2</inf>S<inf>3</inf>-PbS-CsI chalcohalide glasses were prepared and their spectroscopic properties were analyzed based on absorption (ranges from 300 to 3000 nm) and emission (ranges from 1000 to 4700 nm) measurements. Judd-Ofelt analyses were performed to estimate radiative transition parameters for the excited levels. Compositional dependences of near- and mid-infrared luminescences (especially the 1330, 2930 and 4320 nm) excited at 808 nm were investigated and discussed. These novel chalcohalide glasses may have potential uses in 1.3 μm fiber-amplifiers and 2.9 or 4.3 μm mid-infrared laser devices. © 2013 Elsevier B.V. (31 refs.)Main Heading: GlassControlled terms: Absorption spectroscopy - Cesium iodide - Fiber amplifiers - Infrared devices - Luminescence - Optical parametric oscillators - SpectroscopyUncontrolled terms: Chalcohalide glass - Compositional dependence - Judd-Ofelt - Judd-ofelt analysis - Mid-infrared emission - Radiative transitions - Rare earth ions - Spectroscopic propertyClassification Code: 741 Light, Optics and Optical Devices - 801 Chemistry - 804 Chemical Products Generally - 812.3 Glass

Database: Compendex

A gradient threshold auto-focus algorithm

Mo, Chunhong1, 2; Liu, Bo1; Ding, Lu1; Chen, Errui1; Guo, Gao1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 323-327, January 2014; Language: Chinese

; ISSN: 10072276;

Abstract: Traditional gradient auto-focus algorithms have large amount of calculation which will cause the reduction of real-time performance. These algorithms are also weak in anti-noise capability which will result in the decline of unimodality and sensitivity. So a gradient threshold auto-focus algorithm was proposed to improve the focusing performance to meet the requirements of real time and accuracy in auto-focusing subsystem of photoelectric tracking system. The proposed algorithm took the local variance as a local threshold to distinguish the edge pixels from non-edge pixels. Then it used a kind of new standard deviation of the whole image as a global threshold to weaken the effects of noise and background. At last, it used one of traditional gradient auto-focus algorithms to calculate the focusing value of the pre-processed image for clarity-evaluation. The results of lots of experiments show that the proposed algorithm has good real- time performance, strong unimodality, high sensitivity and powerful anti-noise capability. When the proposed algorithm is used in the auto-focusing subsystem of photoelectric tracking system, all the attractive performances remain, which traditional gradient auto-focus algorithm can't achieve. (7 refs.)Main Heading: AlgorithmsControlled terms: Focusing - Gradient methods - Image processing - Photoelectricity - Pixels - Tracking (position)Uncontrolled terms: Auto-focus - Auto-focus algorithm - Evaluation function - Focusing performance - Gradient thresholds - Real time performance - Strong unimodality - ThresholdClassification Code: 921.6 Numerical Methods - 921 Mathematics - 741.1 Light/Optics - 741 Light, Optics and Optical Devices - 723.5 Computer Applications - 723 Computer Software, Data Handling and Applications - 716.2 Radar Systems and Equipment

Database: Compendex

A 66 fs highly stable single wall carbon nanotube mode locked fiber laser

Yu, Zhenhua1; Wang, Yonggang2; Zhang, Xiao1; Dong, Xinzheng1; Tian, Jinrong1; Song, Yanrong1 Source: Laser Physics, v 24, n 1, January 2013

; ISSN: 1054660X, E-ISSN: 15556611; DOI: 10.1088/1054-660X/24/1/015105; Article number: 015105;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Institute of Information Photonics Technology and College of Applied Sciences, Beijing University of Technology, Beijing, 100124, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China

Abstract: We demonstrate a highly stable mode locked fiber laser based on single wall carbon nanotubes The mode locking is achieved by the evanescent field interaction of the propagating light with a single wall carbon nanotube saturable absorber in a microfiber The pulse width is 66 fs which to the best of our knowledge is the shortest pulse achieved in a carbon nanotube mode locked fiber laser The maximum average output power is 26 mW which is about 20 times larger than that of a typical carbon nanotube mode locked fiber laser The center of the wavelength is 1555 nm with 54 nm spectral width The repetition rate is 146 MHz To investigate the laser's stability the output pulses are monitored for 120 h and there is no significant degradation of the laser spectral width or shape © 2014 Astro Ltd. (26 refs.)Main Heading: Locks (fasteners)Controlled terms: Carbon nanotubes - Fiber lasers - Laser mode locking - Pulse generators - Saturable absorbers - Ultrashort pulsesUncontrolled terms: Average output power - Field interactions - Highly stables - Laser-based - Output pulse - Repetition rate - Spectral widths - Ultrashort pulse generationClassification Code: 601.3 Mechanisms - 713.4 Pulse Circuits - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology

Database: Compendex

Video quality assessment via supervised topic model

Guo, Qun1, 2; Lu, Xiaoqiang1; Yuan, Yuan1 Source: 2014 IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014 - Proceedings, p 636-640, September 3, 2014; ISBN-13: 9781479954032; DOI: 10.1109/ChinaSIP.2014.6889321; Article number: 6889321; Conference: 2nd IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014, July 9, 2014 - July 13, 2014; Sponsor: et al.; KC Wong Education Foundation; National Natural Science Foundation of China; Northwestern Polytechnical University; Texas Instruments; The Institute of Electrical and Electronics Engineers (IEEE) Signal Processing Society (SPS);

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient, Optics and Photonics, Chinese Academy of Sciences, Xi'an, Shaanxi, China2 Graduate University of the Chinese Academy of Science, 19A Yuquanlu, Beijing, China

Abstract: Video quality assessment (VQA) plays a very important role in many video processing and communication systems. Since video signals are ultimately delivered to human observers, an accurate objective video quality metric should agree well with judgment of human visual system (HVS). In this paper, a novel full-reference VQA scheme is developed to measure the perceived video quality in both local and global aspects. First, to account for the crucial impact of motion on perception, effective quality features are extracted from the local spatiooral volumes which are generated around the motion trajectories in the video. Second, a statistical model is utilized to discover the latent relation between local quality and global perceived quality. Experimental results on LIVE database demonstrate promising performance of the proposed metric in comparison with state-of-the-art VQA metrics. © 2014 IEEE. (20 refs.)Main Heading: Video signal processingControlled terms: Image qualityUncontrolled terms: Human visual systems - Motion trajectories - Objective video quality metrics - Perceived video quality - Statistical modeling - Topic Modeling - Video quality assessment - Video quality assessments (VQA)Classification Code: 716.4 Television Systems and Equipment - 741 Light, Optics and Optical Devices

Database: Compendex

Exact analytical solution for the mutual compensation of astigmatism using curved mirrors in a folded resonator laser

Wen, Qiao1, 2; Liang, Guowen1, 2; Zhang, Xiaojun1, 2; Liang, Zongsen1, 2; Wang, Yonggang3; Li, Ji1; Niu, Hanben1 Source: IEEE Photonics Journal, v 6, n 6, December 2014

; ISSN: 19430655; DOI: 10.1109/JPHOT.2014.2366160; Article number: 6945338;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Key Lab. of Optoelectronic Devices and Systems of the Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China2 Key Laboratory of Micro-Nano Measuring and Imaging in Biomedical Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: For the first time, to the best of our knowledge, analytical expressions for mutually compensating the curved mirror astigmatism in the two terminal arms of a folded resonator are deduced and experimentally verified. The analytical expressions are derived using the theory of the propagation and transformation of Gaussian beams under few assumptions. Our exact analytical expressions describe the necessary and sufficient conditions for simultaneously compensating astigmatism in two arms of a sequence of two off-axis curved mirrors. The theoretical results indicate that, when the astigmatism compensation expressions are satisfied, the astigmatism introduced by a folded curved mirror can be mutually compensated by another folded curved mirror, even if there is no additional Brewster element inside the cavity. The astigmatism can only be successfully eliminated by using a pair of concave mirrors or convex mirrors. Our analytical expressions can be used to design astigmatically compensated folded resonators without a Brewster element. A typical side-pumped z-shaped cavity Nd:YAG laser is employed to demonstrate the astigmatic compensation. Experimental measurements of the pattern of the laser output beam show that not only the spot intensity profile deformation but, in addition, the phase distortion in the two terminal arms can be simultaneously compensated completely in the cavity, which is in good agreement with the analytical predictions. (15 refs.)Main Heading: Laser mirrorsControlled terms: Adaptive optics - Gaussian beams - Laser resonators - Mirrors - Neodymium lasers - Optical resonators - Pumping (laser)Uncontrolled terms: Analytical expressions - Analytical predictions - Astigmatic compensation - Exact analytical solutions - Laser output beam - Phase compensation - Phase distortions - Spot intensitiesClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744 Lasers

Database: Compendex

Lung nodule detection and segmentation algorithm based on average intensity projection and shift Gaussian model

Qiu, Shi1, 2; Wen, Desheng1; Wang, Lei3 Source: Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument, v 35, n 11, p 2550-2559, November 1, 2014; Language: Chinese

; ISSN: 02543087;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China3 School of Electronic Engineering, Xidian University, Xi'an , China

Abstract: Aiming at the problem that in CT image the blood vessels and nodules may connected that leads to segmentation difficulty, a novel nodule segmentation algorithm is proposed based on average intensity projection (AIP) and shift Gaussian model. Firstly, the AIP method is employed on a 2D CT image to generate an AIP image with local 3D features. Secondly, the region of interest (ROI) is obtained by performing threshold segmentation and morphology transformation on the AIP image. Finally, through establishing the shift Gaussian model the nodules are accurately extracted. The experiments on 30 CT images with blood vessel connection were conducted, the results show that the area overlap measure (AOM) reaches 91% between the proposed algorithm and the professional doctor manual segmentation; the proposed algorithm can achieve effect segmentation of lung nodules with blood vessel connection; however, there is still a risk of miss detection for the lung nodules with weak grey scale and small volume, which needs to be further studied. (16 refs.)Main Heading: Image segmentationControlled terms: Algorithms - Biological organs - Blood vessels - Computerized tomography - Gaussian distribution - Risk assessmentUncontrolled terms: Average intensity projection - Gaussian model - Lung nodule detection - Lung nodule segmentation - Morphology transformations - Segmentation algorithms - The region of interest (ROI) - Threshold segmentationClassification Code: 461.2 Biological Materials and Tissue Engineering - 531 Metallurgy and Metallography - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 801 Chemistry - 921 Mathematics - 922.1 Probability Theory

Database: Compendex

Laser pulse propagation and enhanced energy coupling to fast electrons in dense plasma gradients

Gray, R.J.1; Carroll, D.C.1, 2; Yuan, X.H.1, 5; Brenner, C.M.1, 2; Burza, M.3; Coury, M.1; Lancaster, K.L.2; Lin, X.X.4; Li, Y.T.4; Neely, D.1, 2; Quinn, M.N.1; Tresca, O.1; Wahlström, C.-G.3; McKenna, P.1 Source: New Journal of Physics, v 16, November 28, 2014

; ISSN: 13672630; DOI: 10.1088/1367-2630/16/11/113075; Article number: 113075;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Department of Physics, SUPA, University of Strathclyde, Glasgow, United Kingdom2 Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot, Oxfordshire, United Kingdom3 Department of Physics, Lund University, PO Box 118, Lund, Sweden4 Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing, China5 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Laser energy absorption to fast electrons during the interaction of an ultraintense (1020 Wcm-2), picosecond laser pulse with a solid is investigated, experimentally and numerically, as a function of the plasma density scale length at the irradiated surface. It is shown that there is an optimum density gradient for efficient energy coupling to electrons and that this arises due to strong self-focusing and channeling driving energy absorption over an extended length in the preformed plasma. At longer density gradients the laser filaments, resulting in significantly lower overall energy coupling. As the scale length is further increased, a transition to a second laser energy absorption process is observed experimentally via multiple diagnostics. The results demonstrate that it is possible to signi ficantly enhance laser energy absorption and coupling to fast electrons by dynamically controlling the plasma density gradient. (30 refs.)Main Heading: Electromagnetic wave propagation in plasmaControlled terms: Beam plasma interactions - Electrons - Energy absorption - Laser diagnostics - Laser produced plasmas - Laser pulses - Plasma density - Pulse generatorsUncontrolled terms: Density gradients - Fast electron generation - Irradiated surface - Laser energy absorption - Laser pulse propagation - Laser-plasma interactions - Picosecond laser pulse - Plasma density gradientClassification Code: 713.4 Pulse Circuits - 744.1 Lasers, General - 744.9 Laser Applications - 931.3 Atomic and Molecular Physics - 932.3 Plasma Physics

Database: Compendex

Experimental and theoretical investigations of a tunable dissipative soliton fiber laser

Han, D.D.1 Source: Applied Optics, v 53, n 32, p 7629-7633, November 10, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.007629;

Abstract: Atunable dissipative soliton fiber laser based on carbon nanotubes and the nonlinear polarization rotation (NPR) technique has been investigated experimentally and numerically for the first time to the author's best knowledge. The laser proposed delivers strongly chirped solitons with pulse duration of &sim;220 ps and a spectral width of &sim;5.6 nm. With the NPR-related filtering effect, the output pulses are wavelength tunable over the range from 1566 to 1593nmby adjusting the polarization controller (PC).Numerical results are in good agreement with experimental observations and clearly reveal that the tunable mode-locking operation is attributed to the variation of phase delay caused by the PCs. © 2014 Optical Society of America. (45 refs.)Main Heading: SolitonsControlled terms: Fiber lasers - Locks (fasteners) - Microcomputers - Polarization - YarnUncontrolled terms: Dissipative solitons - Filtering effects - Nonlinear polarization rotation - Numerical results - Polarization controllers - Pulse durations - Theoretical investigations - Wavelength tunableClassification Code: 601.3 Mechanisms - 711.1 Electromagnetic Waves in Different Media - 722.4 Digital Computers and Systems - 741.1.2 Fiber Optics - 819.4 Fiber Products - 931.3 Atomic and Molecular Physics

Database: Compendex

Focus shaping of radial polarized beam based on pupil filter

Zhu, Huafeng1, 2; Wang, Tianyang2; Liu, Pei2; Fu, Jianbo2; Li, Dailin2; Wang, Ning2; Wang, Xiumin2 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, September 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.s126001; Article number: s126001;

Abstract: The optical intensity distribution in the focal volume plays an important role on the performance for many optical systems. Effective manipulation of focused optical intensity distribution can be obtained by using a pupil filter composed by zonal optical diffractive element and zonal double half-wave plate which can modulate both the phase and the direction of polarization of incident radially polarized beam zone by zone, and turn radially polarized beam into zonal sylindrically polarized beam. Numerical simulations of Matlab show that different intensity distributions can be obtained in the focal volume. Using the method, besides the existing doughnut intensity distribution and flattop focal spot in focal plane, the flattop doughnut intensity in the focal plane with hollow three-dimension (3D) pattern is obtained. This result can find potential use in fields such as particle manipulation and caption, laser micromachining, etc. (12 refs.)Main Heading: Fiber optic sensorsControlled terms: Birefringence - Diffractive optical elements - Focusing - Light polarization - MATLAB - Optical devices - Physical opticsUncontrolled terms: Diffractive element - Half waveplate - Intensity distribution - Laser micro-machining - Optical intensities - Particle manipulation - Polarized beams - Radially polarized beamClassification Code: 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Very large mode area optical fiber with complex ring cores

Zhu, Yonggang1; Duan, Kailiang1; Yang, Hening1; Zhao, Baoyin1; Zhao, Wei1 Source: Optik, v 125, n 23, p 7016-7019, December 1, 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.08.083;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: A novel kind of single-mode large-mode-area optical fiber is presented in this paper. The proposed fiber core is composed of high-index central rod and the surrounding multilayer rings. The mode characteristics are discussed considering the fiber structure parameters. The calculation results show that the proposed fiber possesses extreme large mode area of 2975 μm2 with single mode operation at the wavelength of 1.08 μm. Even larger mode area of the complex ring core fiber with single mode output can be achieved by coiling the fiber, due to the significant difference of bending loss between the fundamental mode and the higher-order transverse modes. Such fibers are expected to find applications in the field of fiber lasers and amplifiers. (12 refs.)Main Heading: Fiber amplifiersControlled terms: Fiber lasers - Fibers - Optical fibersUncontrolled terms: Calculation results - Fiber lasers and amplifiers - Fiber structures - Fundamental modes - Large mode area - Mode characteristics - Single mode - Single mode operationClassification Code: 741.1.2 Fiber Optics - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

Distributed real-time networked control architecture for suppressing wind load deformation of Fourier telescope

Cheng, Zhiyuan1; Ma, Caiwen1 Source: Proceedings - 2014 6th International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC 2014, v 2, p 364-367, September 25, 2014; ISBN-13: 9781479949557; DOI: 10.1109/IHMSC.2014.189; Article number: 6911517; Conference: 2014 6th International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC 2014, August 26, 2014 - August 27, 2014; Sponsor: Zhejiang Provincial Natural Science Foundation of China;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an Shanxi, China

Abstract: To advance optical profile accuracy of high-resolution imaging Fourier telescope and improve the real-time of profile error suppressing, the paper proposed a novel real-time networked control scheme integrated Ether CAT(Ethernet for control Automation Technology) field bus with PC-based control model. Based on the high speed transmission principle of EtherCAT field bus it improves the real-time of surface error suppressing induced by wind load and meets the requirements of high resolution imaging, Then it makes good use of powerful clustering control, the open architecture of PC controller to solve cluster control problem of mass distributed drivers in large telescope. The results show that EtherCAT networked control solution has advantages of highest real-time, flexible network control structure, powerful clustering control ability. It can meet the real-time requirement of profile error suppressing caused by wind load in Large Fourier telescope. © 2014 IEEE. (11 refs.)Main Heading: TelescopesControlled terms: Aerodynamic loads - Cluster computing - Computer architecture - Fourier transforms - Image reconstruction - Network architecture - Wind stressUncontrolled terms: Distributed drivers - EtherCAT - Fourier - High speed transmission - High-resolution imaging - Networked controls - PC control - Real time requirementClassification Code: 402 Buildings and Towers - 421 Strength of Building Materials; Mechanical Properties - 651.1 Aerodynamics, General - 657 Space Physics - 722 Computer Systems and Equipment - 722.4 Digital Computers and Systems - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 921.3 Mathematical Transformations

Database: Compendex

Remote-focusing microscopy with long working distance objective lenses

Qi, Yujiao1; Lei, Ming1; Yang, Yanlong1; Yao, Baoli1; Dan, Dan1; Yu, Xianghua1; Yan, Shaohui1; Ye, Tong1 Source: Applied Optics, n 16, p 3473-3478, June 1, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.003473;

Abstract: Remote-focusing microscopy has recently attracted a lot of interest due to its high-speed axial scanning capabilities. In this paper, we modeled remote-focusing microscopy, based on a pair of long working distance objective lenses. Three-dimensional intensity distributions of the point spread functions (PSFs) are calculated, and no significant spherical aberrations are introduced over a large volume of 100 μm × 100 μm × 150 μm. The validity of the scheme is verified by imaging biological samples and microelectronic chips at the imaging depth of 150 μm without introducing aberrations in the experiment. © 2014 Optical Society of America. (16 refs.)Main Heading: FocusingControlled terms: Microelectronics - Optical instrument lenses - Optical transfer functionUncontrolled terms: Axial scanning - Biological samples - Imaging depth - Intensity distribution - Microelectronic chip - Objective lens - Spherical aberrations - Working distancesClassification Code: 713 Electronic Circuits - 714 Electronic Components and Tubes - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Lensless ghost imaging experiments in three different configurations

Xue, Yu-Lang1; Wan, Ren-Gang1; Feng, Fei1; Yao, Yin-Ping1; Zhang, Tong-Yi1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 8, August 1, 2014

; ISSN: 10044213; DOI: 10.3788/gzxb20144308.0823006; Article number: 0823006;

Abstract: To achieve stand-off sensing applications, ghost imaging experiments with pseudothermal light were performed from transmissive to reflective cases. First, ghost images of a transmissive double-slit aperture were retrieved in a setup that both the reference beam and signal beam were collected with two different regions of a single CCD. Then a CCD and a separate bucket detector were used to record the light intensity information of the reference beam and the signal beam, respectively. By calculating the intensity correlation function of the signal beam with no spatial light distribution and the spatial dependent reference beam that does not interact with the object, ghost images of a transmissive object and a reflective object were achieved. In order to design and develop prototype systems field applicable, detailed experimental investigations were performed to compare the effect of system parameters on the quality of imaging in the transmission configuration. The results show that enough high power of light source, large sample numbers, and proper exposure time and spatial frequency bandwidth can lead to ghost image with good resolution and visibility. (24 refs.)Main Heading: Image processingControlled terms: Experiments - Imaging systems - Light sourcesUncontrolled terms: Experimental investigations - Ghost imaging - Intensity correlation functions - Pseudothermal light - Pseudothermal light source - Second orders - Sensing applications - Transmission configurationClassification Code: 741 Light, Optics and Optical Devices - 744 Lasers - 746 Imaging Techniques - 901.3 Engineering Research

Database: Compendex

CFRP variable curvature mirror being capable of generating a large variation of saggitus: Prototype design and experimental demonstration

Zhao, Hui1; Fan, Xuewu1; Pang, Zhihai1; Ren, Guorui1; Wang, Wei1; Xie, Yongjie1; Ma, Zhen1; Du, Yunfei1; Su, Yu1; Wei, Jingxuan2; Xie, Xiaopeng3 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9272, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413458; DOI: 10.1117/12.2065554; Article number: 92720S; Conference: Optical Design and Testing VI, October 9, 2014 - October 10, 2014; Sponsor: Chinese Optical Society (COS); The Society of Photo-Optical Instrumentation Engineers (SPIE);

Abstract: The key to realize non-moving-element optical zooming lies in VCM (variable curvature mirror). In order to obtain a large optical magnification, VCM should be capable of providing a large center deflection and this requires that the mirror material should be robust enough, require less force to deform and have a high ultimate strength. In this paper, CFRP (carbon-fiber-reinforced-polymer) is selected as the mirror material and a prototype VCM has been fabricated. With diameter of 100mm, thickness of 2mm and initial curvature radius of 1740mm, this VCM can provide a center deflection approaching nearly 23um, which proves the feasibility of CFRP in constructing VCM. Compared with the work reported in [Proc. of SPIE, 8725, 87250W, 2013], the center deflection obtained here becomes even larger. © 2014 SPIE. (7 refs.)Main Heading: MirrorsControlled terms: Carbon fiber reinforced plastics - Design - Fiber reinforced plastics - Optical design - Strength of materialsUncontrolled terms: Carbon fiber reinforced polymer - Experimental demonstrations - Initial curvature - Mirror materials - Optical zooming - Prototype designs - Ultimate strength - Variable curvature mirrorClassification Code: 408 Structural Design - 421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 817.1 Polymer Products - 817.2 Polymer Applications - 951 Materials Science

Database: Compendex

Improved adaptive control for wing rock via fuzzy neural network with randomly assigned fuzzy membership function parameters

Rong, Hai-Jun1; Han, Sai2; Bai, Jian-Ming3; Liang, Yong-Qi1 Source: Aerospace Science and Technology, March 18, 2014

; ISSN: 12709638; DOI: 10.1016/j.ast.2014.06.009 Article in PressAuthor affiliation: 1 State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an, ShaanXi, 710049, China2 Institute of Avionics and Flight Control, AVIC Xi'an Aircraft Branch Company, Yanliang, ShaanXi, 710089, China3 Optical Direction and Pointing Technique Research Department, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, ShaanXi, 710119, China

Abstract: Two stable adaptive fuzzy-neural control schemes within the indirect and direct frameworks are proposed to suppress the wing rock occurring at high angles of attack. In the two control strategies, a fuzzy neural network (FNN) with any bounded nonconstant piecewise continuous membership function is used to approximate the system nonlinear dynamics and external disturbances. Differently from the existing techniques, the parameters of the fuzzy membership functions are determined based on the recently developed fuzzy-neural algorithm named online sequential fuzzy extreme learning machine (OS-Fuzzy-ELM) where the fuzzy membership function parameters need not be adjusted and could randomly be generated according to any given continuous probability distribution without any prior knowledge. This simplifies the design of the controllers. Furthermore to ensure stable control performance, the tuning laws of the consequent parameters are derived using the projection algorithm and Lyapunov stability theorem. The merits of the proposed control schemes lie in the simplicity, robustness and stability, which manifests they can be applied for online learning and real-time control. In order to evaluate the performance of the proposed two control schemes, a comparison between a neural control, a fuzzy control and a fuzzy-neural control is carried out on various initial conditions. Results indicate the performance of the proposed controllers is superior using the randomly assigned fuzzy membership function parameters. © 2014 Elsevier Masson SAS.Main Heading: ControllersControlled terms: Fuzzy control - Fuzzy neural networks - Membership functions - Probability distributions - Real time controlUncontrolled terms: Continuous probability distribution - External disturbances - Extreme learning machine - Fuzzy membership function - Fuzzy-Neural algorithms - High angles of attack - Lyapunov stability theorem - Projection algorithmsClassification Code: 723.4 Artificial Intelligence - 731 Automatic Control Principles and Applications - 732 Control Devices - 732.1 Control Equipment - 921 Mathematics - 922.1 Probability Theory

Database: Compendex

Testing of large relative aperture convex aspheric lens with doublets

Chen, Qin-Fang1; Ma, Zhen1; Zhao, Meng1; Fang, Hu1; Wang, Hu1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 3, March 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144303.0322004; Article number: 0322004;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 The Space Optical Technology Research Department, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: It is difficult to fabricate and test convex aspherical surfaces, especially for steep convex aspheical surfaces. Based on the analysis of the conventional null test, a simple test system with cemented doublet for two steep convex ellipsoids was discussed. The wavefront of the both test system was less than 1/30λ RMS (Root Meat Square, λ=632.8 nm). The convex aspheric lens had their successful application in practical optical system. The result showed that the null test for convex aspheric lens discussed in this paper is valid. Compared with the traditional test method, the cemented doublet offsets the spherical aberration generated by the sphere surface of the lens. So the proposed test method decreases the amount of the spherical aberration generated by the aspherical lens, with fewer elements, and reduces the system's alignment difficulty. It was demonstrated to be an effective, high-precision testing method. (15 refs.)Main Heading: TestingControlled terms: Aberrations - Optical instrument lenses - Optical systemsUncontrolled terms: Aspheric lens - Doublet - Ellipsoid - Large relative aperture - Null testClassification Code: 423.2 Non Mechanical Properties of Building Materials: Test Methods - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems

Database: Compendex

The performance of new polymer solar cells based on thiophene and thienyl-quinoxaline with the post treatments

Gao, Bowen1, 3; Gao, Chao2; Wu, Haimei2; Que, Wenxiu3; Wei, Wei1 Source: Materials Letters, v 122, p 74-77, May 1, 2014

; ISSN: 0167577X; DOI: 10.1016/j.matlet.2014.01.140;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precwasion Mechanics, Chinese Academy of Science (CAS), Xian, Shaanxi 710119, China2 Xian Modern Chemwastry Research Institute, Xian, Shaanxi 710065, China3 School of Electronics and Information Engineering, Xian Jiaotong University, Xian, Shaanxi 710049, China

Abstract: A new low band gap (optical band gap=1.62 eV) polymer (TTQ) based on thiophene and thienyl-quinoxaline by substituting phenyl in quinoxaline unit for thiophene rings was synthesized and characterized for application in polymer solar cells (PSCs). The optical band gap (E<inf>g</inf>opt) deduced from the onset (765 nm) of the polymer absorption spectrum in the films was 1.62 eV, which was less than those of the polymers TQ and FTQ and was closer to the ideal band gap of a donor for BHJ polymer solar cell applications. For the optimized polymer solar cell of TTQ:PC<inf>71</inf>BM, 1:1 w/w, in DCB solution, a PCE over 1.41% with V<inf>oc</inf> of 0.70 V, J<inf>sc</inf> of 3.89 mA/cm2, and fill factor (FF) of 55% under AM1.5 conditions was achieved by solvent annealing in comparing with those of solvent surface treatment devices (PCE of 1.34%) and thermal annealing devices (PCE of 1.10%). © 2014 Elsevier B.V. (18 refs.)Main Heading: PolymersControlled terms: Absorption spectroscopy - Annealing - Energy gap - Optical band gaps - Polymer films - Solar cells - Solvents - Surface treatment - ThiopheneUncontrolled terms: Low band gap - Polymer solar cell (PSCs) - Polymer Solar Cells - Post treatment - Solvent annealing - Thermal-annealing - Thienyl-quinoxaline - Thiophene ringClassification Code: 933 Solid State Physics - 931.3 Atomic and Molecular Physics - 931 Classical Physics; Quantum Theory; Relativity - 815.1 Polymeric Materials - 804.1 Organic Compounds - 802 Chemical Apparatus and Plants; Unit Operations; Unit Processes - 801 Chemistry - 741 Light, Optics and Optical Devices - 615.2 Solar Power - 539 Metals Corrosion and Protection; Metal Plating - 537.1 Heat Treatment Processes

Database: Compendex

Bound state of dissipative solitons in a nanotube-mode-locked fiber laser

Yun, Ling1; Han, Dongdong1 Source: Optics Communications, v 313, p 70-73, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2013.10.005;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The bound state of dissipative solitons (DSs) in a nanotube-based erbium-doped fiber laser is observed experimentally for the first time to our best knowledge. The bound-state DSs exhibit a rectangular spectrum profile accompanied by high-contrast modulated fringes on the top. The pulse duration of DSs is estimated as ~3.6 ps and the pulse-pulse separation is ~30 ps. The propagation dynamics of the bound-state DSs are further investigated by utilizing single-mode fiber with different lengths. It is found that the pulses can be compressed to ~208 fs and subsequently broadened linearly along the extracavity fiber, while the pu separation between the two bound-state DSs remains constant. © 2013 Elsevier B.V. (52 refs.)Main Heading: NanotubesControlled terms: Fiber lasers - Pulse generators - Single mode fibers - SolitonsUncontrolled terms: Bound state - Dissipative solitons - Erbium doped fiber laser - High contrast - Propagation dynamics - Pulse durations - Spectrum profile - Ultra-fast pulse generationClassification Code: 713.4 Pulse Circuits - 741.1.2 Fiber Optics - 761 Nanotechnology - 931.3 Atomic and Molecular Physics

Database: Compendex

Enhanced 2.7 lm emission of Er/Pr-codoped water-free fluorotellurite glasses

Zhan, Huan1, 2; Zhang, Aidong1; He, Jianli1; Zhou, Zhiguang1; Li, Lu1, 2; Shi, Tengfei1; Xiao, Xusheng1; Si, Jinhai1, 2; Lin, Aoxiang1 Source: Journal of Alloys and Compounds, v 582, p 742-746, 2014

; ISSN: 09258388; DOI: 10.1016/j.jallcom.2013.07.211;

Publisher: Elsevier LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an 710119, China2 Key Laboratory for Physical Electronics, Devices of the Ministry of Education, Xi'an Jiaotong University, Xianning-xilu 28, Xi'an 710049, China

Abstract: Using physical and chemical dehydration technique and traditional melting and quenching method, we fabricated a group of Er/Pr-codoped water-free fluorotellurite glasses with composition of 60TeO<inf>2</inf>- 30ZnF <inf>2</inf>-10NaF (TZNF60, mol%). The lifetime τf of 4I <inf>11/2</inf>→4I<inf>13/2</inf> transition, directly measured under the excitation by an optical parametric oscillator (OPO) laser system at 978 nm, in Er/Pr codoped fluorotellurite glasses is 1.37-1.55 ms, longer than that of Er-doped tellurite oxide (215 μs) and Er-doped fluorotellurite glasses (1.07 ms). The introduction of Pr3+ ions into Er-doped system increases the emission intensity at 2.71 μm (Er: 4I <inf>11/2</inf>→4I<inf>13/2</inf>) and emission cross section as well. These advances partially arise from the absence of OH groups and low phonon energy with the addition of large amount of fluorides into oxide-based host glasses. With the high quantum efficiency and large figure of merit, Er/Pr-TZNF60 glass can be potentially a promising material for the development of mid-infrared fiber lasers at around 2.7 μm. © 2013 Published by Elsevier B.V. (33 refs.)Main Heading: Doping (additives)Controlled terms: Energy transfer - Erbium - Fiber lasers - Fiber optics - Fluorescence - Glass - Infrared radiation - Laser excitation - Optical parametric oscillators - Tellurium compoundsUncontrolled terms: Emission cross section - Emission intensity - Figure of merits - Fluoro-tellurite glass - High quantum efficiency - Low phonon energies - Midinfrared lasers - Rare earth doped materialsClassification Code: 812.3 Glass - 804.1 Organic Compounds - 801.4 Physical Chemistry - 801 Chemistry - 741 Light, Optics and Optical Devices - 641.2 Heat Transfer - 547.2 Rare Earth Metals

Database: Compendex

A new infrared thermal design based on GWIR uncooled detector

Xie, Qing Sheng1; Yi, B.1; Liu, Wei1; Duan, Cheng Peng1; Chen, Yao Hong1 Source: Advanced Materials Research, v 1049-1050, p 1249-1252, 2014

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038353140; DOI: 10.4028/www.scientific.net/AMR.1049-1050.1249; Conference: 4th International Conference on Intelligent System and Applied Material, GSAM 2014, August 23, 2014 - August 24, 2014;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanical of CAS, Xian, China

Abstract: The infrared detector is the kernel of an infrared thermal imager. Usually it is the most expensive device. This paper describes a new infrared thermal design, based on an uncooled infrared detector with high performance and low price. It describes the specifications of the infrared detector and illustrates detailed the circuit to driver the infrared detector, include pivotal functions like TEC control and bias-voltages generation. The software to obtain image, correct non-uniformity and enhancement image is discussed also. At last, some infrared images prove the correctness of this design. © (2014) Trans Tech Publications, Switzerland. (5 refs.)Main Heading: Infrared detectorsControlled terms: Design - Image processing - Infrared imaging - Intelligent systemsUncontrolled terms: Infrared thermal imager - IR images - Non-uniformities - Thermal designs - Uncooled detectors - Uncooled infrared detectorsClassification Code: 408 Structural Design - 723.4 Artificial Intelligence - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 746 Imaging Techniques

Database: Compendex

Action recognition based on semantic feature description and cross classification

Zhao, Yang1, 3; Wang, Qi2; Yuan, Yuan1 Source: 2014 IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014 - Proceedings, p 626-630, September 3, 2014; ISBN-13: 9781479954032; DOI: 10.1109/ChinaSIP.2014.6889319; Article number: 6889319; Conference: 2nd IEEE China Summit and International Conference on Signal and Information Processing, IEEE ChinaSIP 2014, July 9, 2014 - July 13, 2014; Sponsor: et al.; KC Wong Education Foundation; National Natural Science Foundation of China; Northwestern Polytechnical University; Texas Instruments; The Institute of Electrical and Electronics Engineers (IEEE) Signal Processing Society (SPS);

Abstract: Action recognition is a challenging topic in computer vision. In this work, we present a novel method for action recognition which is based on two claimed contributions: semantic feature description and cross classification. The designed descriptor is combined by several local 3D-SIFT and is informative and distinctive, reflecting the spatiooral clues of the video. The cross classification effectively combines the feature localization and action categorization together. The proposed method is justified on a popular dateset named UCF50 and the experimental results demonstrate that our method outperforms the state-of-the-art competitors. © 2014 IEEE. (23 refs.)Main Heading: Classification (of information)Controlled terms: Computer vision - SemanticsUncontrolled terms: 3DSIFT - Action recognition - Descriptors - Semantic features - State of the artClassification Code: 723.5 Computer Applications - 903.1 Information Sources and Analysis - 903.2 Information Dissemination

Database: Compendex

Color management of sRGB color space for HDR digital camera

Guo, Huinan1; Cao, Jianzhong1; Wang, Hua1; Zhang, Jian1; Yang, Hongtao1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, p 238-242, December 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Digital imaging devices require color space characterization while transferring or showing image between various devices which is a crucial part of color management for digital devices. In order to keep the color reproduction ability for output image, a high dynamic range digital (HDR) camera requires characterization based on the device properties. For existing characterization algorithms, which are in most cases for 8-bit-digital cameras, the processes of transformation matrix calibration are involved in some complex approaches, which are easy to cause system errors and influence the precision of color space transformation matrix. Accordingly, a color management approach was proposed for a high dynamic range colorful digital camera that using a color space mapping from camera RGB space to CIE1931 XYZ color space to estimate the function relation between two color spaces and using the least square method to achieve color matrix calibration. Eventually the camera RGB color space was transformed to sRGB standard color space which achieves characterization for HDR camera. Experimental results show that this method is of good robustness and easy to realize as well as the mean square error is less than 0.08. ©, 2014, Chinese Society of Astronautics. All right reserved. (11 refs.)Main Heading: ColorControlled terms: Calibration - Characterization - Color printing - Computer vision - Digital cameras - Digital devices - Least squares approximations - Linear transformations - Mean square error - Video camerasUncontrolled terms: Color management - Color space transformation - Color-space mappings - Digital imaging devices - HDR - High dynamic range - Least square methods - Transformation matricesClassification Code: 721 Computer Circuits and Logic Elements - 731.1 Control Systems - 741.1 Light/Optics - 741.2 Vision - 742.2 Photographic Equipment - 745.1 Printing - 921.3 Mathematical Transformations - 921.6 Numerical Methods - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments - 951 Materials Science

Database: Compendex

Prediction of length-of-day using gaussian process regression

Lei, Yu1, 2; Guo, Min3; Cai, Hongbing1; Hu, Dandan3; Zhao, Danning1, 2 Source: Journal of Navigation, v 68, n 3, p 563-575, May 27, 2015

; ISSN: 03734633, E-ISSN: 14697785; DOI: 10.1017/S0373463314000927;

Publisher: Cambridge University PressAuthor affiliation: 1 National Time Service Center, Chinese Academy of Sciences, China2 University of Chinese Academy of Sciences, China3 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, China

Abstract: The predictions of Length-Of-Day (LOD) are studied by means of Gaussian Process Regression (GPR). The EOP C04 time-series with daily values from the International Earth Rotation and Reference Systems Service (IERS) serve as the data basis. Firstly, well known effects that can be described by functional models, for example effects of the solid Earth and ocean tides or seasonal atmospheric variations, are removed a priori from the C04 time-series. Only the differences between the modelled and actual LOD, i.e. the irregular and quasi-periodic variations, are employed for training and prediction. Different input patterns are discussed and compared so as to optimise the GPR model. The optimal patterns have been found in terms of the prediction accuracy and efficiency, which conduct the multi-step ahead predictions utilising the formerly predicted values as inputs. Finally, the results of the predictions are analysed and compared with those obtained by other prediction methods. It is shown that the accuracy of the predictions are comparable with that of other prediction methods. The developed method is easy to use. © 2015 The Royal Institute of Navigation. (20 refs.)Controlled terms: accuracy assessment - numerical model - prediction - regression analysis - stochasticity - time seriesClassification Code: 901 Geobase: Related Topics

Database: GEOBASE

Double-mode electrostatic dispersive prism for compressing electron pulse

Wang, C.1; Kang, Y.2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9233, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628412871; DOI: 10.1117/12.2064943; Article number: 923327; Conference: International Symposium on Photonics and Optoelectronics 2014, SOPO 2014, August 22, 2014 - August 24, 2014; Sponsor: Ningbo University; Tianjin University; Wuhan University;

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, China Academy of Sciences, Xi'an, China2 School of Science, Air Force Engineering University, Xi'an, China

Abstract: The generalized theory of double-mode electrostatic dispersing prism for time-domain compressing electron pulse is presented. The fundamental difference between the two modes of o mode and e mode lies in the dispersive dependence of electron's time of flight on its initial kinetic energy at prism entrance: the electrons with higher initial axial energy definitely have longer time of flight for o mode, while not the case for e mode, which results from the electron pulse's Ushaped motion in the prism. The dispersive dependence of time of flight constitutes the mechanism of electron pulse compression for each mode. An example is given to demonstrate the issue of parameter choosing for the prism and to verify its tunable performance of electron pulse compression. (14 refs.)Main Heading: ElectronsControlled terms: Electrostatics - Kinetic energy - Kinetics - Optoelectronic devices - Photonics - Prisms - Pulse compressionUncontrolled terms: Dispersive prisms - Double-mode - Electron pulse - Generalized theory - Initial kinetics - Time domain - Time of flight - Tunable performanceClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 741.3 Optical Devices and Systems - 931 Classical Physics; Quantum Theory; Relativity - 931.1 Mechanics

Database: Compendex

Infrared small target detection based on bilateral filtering algorithm with similarity judgments

Li, Yanbei1, 2; Li, Yan1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9300, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413861; DOI: 10.1117/12.2070949; Article number: 93000P; Conference: International Symposium on Optoelectronic Technology and Application 2014: Infrared Technology and Applications, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Infrared small target detection is part of the key technologies in infrared precision-guided, search and track system. Resulting from the relative distance of the infrared image system and the target is far, the target becomes small, faint and obscure. Furthermore, the interference of background clutter and system noise is intense. To solve the problem of infrared small target detection in a complex background, this paper proposes a bilateral filtering algorithm based on similarity judgments for infrared image background prediction. The algorithm introduces gradient factor and similarity judgment factor into traditional bilateral filtering. The two factors can enhance the accuracy of the algorithm for smooth region. At the same time, spatial proximity coefficients and gray similarity coefficient in the bilateral filtering are all expressed by the first two of McLaughlin expansion, which aiming at reducing the time overhead. Simulation results show that the proposed algorithm can effectively suppress complex background clutter in the infrared image and enhance target signal compared with the improved bilateral filtering algorithm, and it also can improve the signal to noise ratio (SNR) and contrast. Besides, this algorithm can reduce the computation time. In a word, this algorithm has a good background rejection performance. © 2014 SPIE. (10 refs.)Main Heading: Signal to noise ratioControlled terms: Algorithms - Clutter (information theory) - Infrared imaging - Infrared radiation - Nonlinear filtering - Signal detection - Signal filtering and predictionUncontrolled terms: Background prediction - Background rejection - Bilateral filtering - Complex background - Infrared image systems - Infrared small targets - Relative distances - Similarity judgmentsClassification Code: 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741.1 Light/Optics - 746 Imaging Techniques - 921 Mathematics

Database: Compendex

High efficient CEP-stabilized infrared optical parametric amplifier made from a BBO single crystal

You, Lang-Fang1, 2; Ling, Wei-Jun1, 2; Li, Ke1; Zhang, Ming-Xia1; Zuo, Yin-Yan1; Wang, Yi-Shan2 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 21, November 5, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.214203; Article number: 214203;

Publisher: Institute of Physics, Chinese Academy of SciencesAuthor affiliation: 1 Institute of Laser Technology, Tianshui Normal University, Tianshui, China2 State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, China

Abstract: We demonstrate an efficient tunable phase-stabilized near-infrared optical parametric amplifier (OPA) made from a BBO (β-BaB<inf>2</inf>O<inf>4</inf>) single crystal in this paper. By using the seeded white-light continuum produced by CEP(carrier envelop phase)-stabilized femtosecond laser amplifier system which is seeded into the two stages of a type II OPA system, the pump-to-signal conversion efficiency of 34% can be achieved at 1350 nm. The CEP jitter of amplified pulses measured by an f-2f interferometer is 137 mrad in 30 minutes. This paper demonstrates a simple, feasible and efficient way to produce tunable femtosecond pulses with CEP control. (19 refs.)Main Heading: Optical parametric amplifiersControlled terms: Electromagnetic pulse - Infrared devices - Light amplifiers - Pumping (laser) - Single crystals - Ultrafast lasers - Ultrashort pulsesUncontrolled terms: Amplified pulse - Attosecond pulse - Carrier envelop phase - Optical parameter amplifiers - Optical parametric amplifiers (OPA) - Pump-to-signal conversion - Tunable femtosecond pulse - White-light continuumClassification Code: 701 Electricity and Magnetism - 714 Electronic Components and Tubes - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 933.1 Crystalline Solids

Database: Compendex

Efficient closed-loop multiple-view registration

Shao, Xiaowei1, 2; Shi, Yun3, 4; Zhao, Huijing5; Li, Xuelong6; Shibasaki, Ryosuke4 Source: IEEE Transactions on Intelligent Transportation Systems, v 15, n 6, p 2524-2538, December 1, 2014

; ISSN: 15249050; DOI: 10.1109/TITS.2014.2319352; Article number: 6818435;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Earth Observation Data Integration and Fusion Research Initiative, University of Tokyo, Tokyo, Japan2 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, China3 Key Laboratory of Agri-informatics, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Beijing, China4 Center for Spatial Information Science, University of Tokyo, Tokyo, Japan5 State Key Laboratory of Machine Perception, Peking University, Beijing, China6 Center for Optical Imagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an, China

Abstract: Registering multiple views is an essential and challenging problem for many intelligent transportation applications that employ a mobile sensing platform or consist of multiple stationary sensors. In this paper a novel algorithm is presented for multiple-view registration under a loop closure constraint. Different from most existing methods, which use general optimization techniques, our method studies the mechanism of adjusting the poses of views in a loop and provides a highly efficient and accurate solution. We prove that translation vectors can be decoupled if the same point set is used in each view to associate the previous and subsequent views, leading to our solution for such decouplable cases. If this condition does not hold, an exact solution of translation vectors is provided when rotation parameters are given, which results in our iterative solution for general cases by updating rotation and translation alternately. In our method, the effect of the accumulated pose error in a loop can be distributed to all views efficiently through loop factors, and only a few iterations are needed. Most important of all, in each iteration our method has linear computational complexity with respect to the number of views, which is much superior to that of state-of-the-art methods. A series of experiments was conducted, involving simulation of thousands of views and real vehicle-borne sensing data that include 65 371 point pairs in 352 views. Experimental results show that our proposed method is not only stable and highly efficient but also provides competitive accuracy relative to existing methods. (52 refs.)Main Heading: Iterative methodsControlled terms: Algorithms - Computational complexityUncontrolled terms: General optimizations - Intelligent transportation - Loop closure - Loop closure constraints - Matrix exponentiated gradients - Mobile sensing platforms - Multiple-view - State-of-the-art methodsClassification Code: 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 723 Computer Software, Data Handling and Applications - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

Shaping algorithm for laser spot

Wang, Feng1, 2; Luo, Jianjun1; Li, Ming2; Deng, Yue2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 12, p 3937-3940, December 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 School of Astronautics, Northwestern Polytechnical University, Xi'an, China2 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an, China

Abstract: In order to eliminate the backscattering phenomenon of the infrared laser sport images, or make the distribution of laser spot's gray levels reasonable, a backscattering suppression algorithm based on the spot center of gravity and an algorithm for compensating the gray levels of a laser spot were proposed. The backscattering suppression algorithm was based on extracting the laser spot's center of gravity. Then, the radius of the laser spot can be determined. Finally, the gray levels of the image should be decided by the set threshold. The algorithm for compensating the gray levels of the laser spot was based on determining the laser spot's edge points. Then, the center of the laser spot can be calculated. After that, the center should be corrected through the intensity of regional energy, and the radius of the laser spot would be confirmed. Finally, the gray levels of the laser spot were adjusted through the laser spot's center and radius. The experiment results of these two algorithms and their analyses were shown. Research proves that the backscattering suppression algorithm can substantially eliminate the backscattering phenomenon in the laser spot image, and the distribution of laser spot's gray levels is improved. The images which are processed by the algorithms are suitable for further analysis in engineering experiments or real-time observation. (6 refs.)Main Heading: AlgorithmsControlled terms: BackscatteringUncontrolled terms: Backscattering phenomenon - Center of gravity - Engineering experiments - Laser spots - On the spots - Real time observation - Shaping algorithm - Suppression algorithmClassification Code: 711 Electromagnetic Waves - 723 Computer Software, Data Handling and Applications - 921 Mathematics

Database: Compendex

Global method based on Tao stereo matching framework

Qi, Min1; Cao, Jianzhong1; Zhou, Zuofeng1; Gao, Bo1; Guo, Huinan1; Yang, Lei1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 9, p 3122-3127, September 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China

Abstract: Traditional stereo matching based on global optimization is of computational complex which is poor to get accuracy matching result for the pixels in occlusion and depth discontinuity region. An efficient method of stereo matching was proposed, which was based on Tao stereo matching framework. Firstly, the initial matching disparity was obtained by the enhanced local method. Then occlusion and mismatched pixels were applied from reliable pixels using the robust method and named unreliable pixels, then reliable pixels and presupposition of disparity plane were used to refine the unreliable disparity. Finally, in order to improve the disparity accuracy in low texture region, an enhanced belief propagation method was used to optimize the refined initial disparity, which had adaptive convergence threshold. Experimental results demonstrate that our method can reduce the error matching rate effectively, improve the matching accuracy in occlusion and depth discontinuity region, reduce the computational complexity as well as improve matching speed. (10 refs.)Main Heading: Stereo image processingControlled terms: Biometrics - Computational complexity - Global optimization - Image segmentation - PixelsUncontrolled terms: Accuracy matching - Belief propagation - Depth discontinuities - Error matching - Global methods - Matching speed - Robust methods - Stereo matchingClassification Code: 461 Bioengineering and Biology - 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 723 Computer Software, Data Handling and Applications - 732 Control Devices - 921.5 Optimization Techniques

Database: Compendex

Realistic action recognition via sparsely-constructed Gaussian processes

Liu, Li1, 2; Shao, Ling1, 2; Zheng, Feng2; Li, Xuelong3 Source: Pattern Recognition, v 47, n 12, p 3819-3827, December 1, 2014

; ISSN: 00313203; DOI: 10.1016/j.patcog.2014.07.006;

Publisher: Elsevier LtdAuthor affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, United Kingdom3 State Key Laboratory of Transient Optics and Photonics, XIOPM, Chinese Academy of Sciences, Xi'an, China

Abstract: Realistic action recognition has been one of the most challenging research topics in computer vision. The existing methods are commonly based on non-probabilistic classification, predicting category labels but not providing an estimation of uncertainty. In this paper, we propose a probabilistic framework using Gaussian processes (GPs), which can tackle regression problems with explicit uncertain models, for action recognition. A major challenge for GPs when applied to large-scale realistic data is that a large covariance matrix needs to be inverted during inference. Additionally, from the manifold perspective, the intrinsic structure of the data space is only constrained by a local neighborhood and data relationships with far-distance usually can be ignored. Thus, we design our GPs covariance matrix via the proposed &ell;1construction and a local approximation (LA) covariance weight updating method, which are demonstrated to be robust to data noise, automatically sparse and adaptive to the neighborhood. Extensive experiments on four realistic datasets, i.e., UCF YouTube, UCF Sports, Hollywood2 and HMDB51, show the competitive results of &ell;1-GPs compared with state-of-the-art methods on action recognition tasks. © 2014 Elsevier Ltd. (30 refs.)Main Heading: Gaussian distributionControlled terms: Computer vision - Covariance matrix - Gaussian noise (electronic)Uncontrolled terms: Action recognition - Data relationships - Gaussian Processes - Intrinsic structures - Local approximation - Local neighborhoods - Probabilistic framework - State-of-the-art methodsClassification Code: 713 Electronic Circuits - 716 Telecommunication; Radar, Radio and Television - 723.5 Computer Applications - 921 Mathematics - 922 Statistical Methods

Database: Compendex

Square wave modulation to eliminate the influence of Wollaston prism nonlinear coefficients on spatial angle measurement

Lu, Weiguo1; Wu, Yiming1; Gao, Limin1; Li, Chunyan1, 2; Xiao, Maosen1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 7, p 2198-2203, July 25, 2014; Language: Chinese

; ISSN: 10072276;

Abstract: A spatial angle measurement model was established based on polarizing beam splitting principle of Wollaston prism. The influence of exit light intensity from Wollaston prism on the system angle measurement accuracy was made by theoretical analysis and simulation briefly. The simulation results show that the exit light intensity deviates from the Malus' law, a certain nonlinear deviation is presented, and there is a great influence of the nonlinear deviation of Wollaston prism on the angle measurement accuracy of spatial angle measurement, the practical value of the device is reduced. Furthermor, a method of square wave magneto- optical modulation was presented to improve the angle measurement accuracy, which effectively eliminated the influence of nonlinear coefficients of Wollaston prism, fluctuations of magneto-optical glass modulation, differences of circuit gain and fluctuations of the light intensity. Finally, by doing relevant experiments, the system angle measurement accuracy can reach 15″ in the range of-8° to+8° by using this method. (10 refs.)Main Heading: Nonlinear opticsControlled terms: Angle measurement - Modulation - Optical glass - Polarimeters - PrismsUncontrolled terms: Analysis and simulation - Measurement accuracy - Non-linear deviation - Nonlinear coefficient - Nonlinearity coefficient - Polarizing beams - Square wave modulation - Wollaston prismClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741.1.1 Nonlinear Optics - 741.3 Optical Devices and Systems - 941.3 Optical Instruments - 943.2 Mechanical Variables Measurements

Database: Compendex

Optimization of PID parameters based on improved particle-swarm-optimization

Fan, Xinming1, 2; Cao, Jianzhong1; Yang, Hongtao1; Dong, Xiaokun1; Liu, Chen1, 2; Gong, Zhendong1, 2; Wu, Qingquan1, 2 Source: Proceedings - 2013 International Conference on Information Science and Cloud Computing Companion, ISCC-C 2013, p 393-397, December 3, 2014; ISBN-13: 9781479952458; DOI: 10.1109/ISCC-C.2013.99; Article number: 6973624; Conference: 2013 International Conference on Information Science and Cloud Computing Companion, ISCC-C 2013, December 7, 2013 - December 8, 2013;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shanxi Province, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Because the PID parameter settings obtained by classical method fail to achieve the best control performances, this paper proposes an improved particle swarm optimization (IPSO) algorithm with non-linear inertial weight changes and border buffer. Unlike the original PSO, the inertial weight changes instead of linearly. In addition, we provide a border buffer to the slopping-over particles, making them to fall in the explored space of optima to enhance the diversity of the particle swarm. The simulation experiments show that the system whose parameters are optimized by IPSO has better performances. Meanwhile, it proves the effectiveness of the improved particle swarm optimization. (13 refs.)Main Heading: Particle swarm optimization (PSO)Controlled terms: Reactive power - Three term control systemsUncontrolled terms: Better performance - Classical methods - Control performance - Improved particle swarm optimization algorithms - Parameters tuning - Particle swarm - PID controllers - System simulationsClassification Code: 706 Electric Transmission and Distribution - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems

Database: Compendex

Effects of mirror surface roughness on encircled energy for far ultraviolet telescopes

Fu, Huaiyang1, 2; Zhou, Sizhong1; Jiang, Kai1; Mei, Chao1, 2; Zhang, Hui1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 8, p 2562-2567, August 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: The image quality was degraded by the surface roughness of astronomy imaging applications, and it might be specified in terms of fractional encircled energy. Relationship between the encircled energy and roughness RMS was qualitatively analysed by cosine phase grating model, moreover, the effective transfer function of the surface was built drew on Fourier optical linear systems theory, then the associated angle spread function as well as encircled energy were deduced. For 1 216Å(1Å=0.1 nm) far ultraviolet telescope which closed to diffraction limit and in the terms of primary and secondary mirrors roughness RMS were far less than one wavelength, encircled energy versus RMS roughness and autocovariance width could be infered. So resolution error caused by surface roughness was limited in 0.171 5, the manufacturing requirement for mirrors roughness RMS was less than 31 Åand autocovariance width was longer than one wavelength. It's useful for our manufacturing guiding significance. (10 refs.)Main Heading: Surface roughnessControlled terms: Diffraction - Diffraction gratings - Linear systems - Manufacture - Mirrors - TelescopesUncontrolled terms: Autocovariances - Diffraction limits - Encircled energy - Guiding significances - Imaging applications - Mirror surface roughness - Phase grating - Secondary mirrorClassification Code: 537.1 Heat Treatment Processes - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 921 Mathematics - 931.2 Physical Properties of Gases, Liquids and Solids - 961 Systems Science

Database: Compendex

Large femtosecond third-order optical nonlinearity of Bi<inf>3.15</inf>Nd<inf>0.85</inf>Ti<inf>3</inf>O<inf>12</inf> ferroelectric thin films

Li, S.1; Zhong, X.L.1; Cheng, G.H.2; Liu, X.2; Wang, J.B.1; Huang, J.1; Song, H.J.1; Tan, C.B.1; Li, B.1; Zhou, Y.C.1 Source: Applied Physics Letters, v 105, n 19, November 10, 2014

; ISSN: 00036951; DOI: 10.1063/1.4900758; Article number: 192901;

Publisher: American Institute of Physics Inc.Author affiliation: 1 School of Materials Science and Engineering, Xiangtan University, Hunan Xiangtan, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, CAS, Shanxi Xi'an, China

Abstract: Both the linear and nonlinear optical properties of Bi<inf>3.15</inf>Nd<inf>0.85</inf>Ti<inf>3</inf>O<inf>12</inf> (BNT<inf>0.85</inf>) ferroelectric thin films deposited on quartz substrates were investigated. The fundamental optical constants were determined as a function of light wavelength by optical transmittance measurements. By performing single-beam Z-scan experiments with femtosecond laser pulses at a wavelength of 800nm, the two-photon absorption (TPA) coefficient β and third-order nonlinear refraction index γ were measured to be 1.15×102cm/GW and -8.15×10-3 cm2/GW, respectively. The large TPA is attributed to an indirect transition process via the intermediate energy levels and the large refractive nonlinearity is the result of the electronic polarization and ferroelectric polarization arisen from the femtosecond midinfrared radiation. The results indicate that the BNT<inf>0.85</inf> thin film is a promising candidate for applications in nonlinear photonic devices. © 2014 AIP Publishing LLC. (34 refs.)Main Heading: Nonlinear opticsControlled terms: Ferroelectric films - Ferroelectric thin films - Ferroelectricity - Laser pulses - Luminescence of organic solids - Optical properties - Photonic devices - Polarization - Quartz - Thin films - Two photon processes - Ultrafast lasers - Ultrashort pulsesUncontrolled terms: Electronic polarization - Ferroelectric polarization - Linear and nonlinear optical properties - Nonlinear photonic devices - Nonlinear refraction index - Refractive non-linearity - Third-order optical nonlinearities - Transmittance measurementsClassification Code: 482.2 Minerals - 701.1 Electricity: Basic Concepts and Phenomena - 708.1 Dielectric Materials - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 741.1.1 Nonlinear Optics - 744.1 Lasers, General

Database: Compendex

Research on nonsmooth H<inf>∞</inf> control for the adaptive optics system

Zhao, Xin1, 2; Ma, Cai-Wen1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 9, September 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144309.0901003; Article number: 0901003;

Abstract: To design an adaptive optics robust controller with the characteristics of simple structure and low orders, a nonsmooth H<inf>∞</inf> control method for the adaptive optics system was proposed. The full order H<inf>∞</inf> controller and the reduced order H<inf>∞</inf> controller were designed by conventional H<inf>∞</inf> control method combined with model reduction based on Hankel singular values. And the orders of the controllers are 226 and 163 respectively, whereas the nonsmooth H<inf>∞</inf> controller designed for the system is simply the product of a constant matrix and a 4 order single input single output transfer function. For the sake of control performance verification and comparation, the dynamic atmospheric turbulence wavefront phase was simulated, as well as the residual wavefront phase corrected by adaptive optics systems with the full order H<inf>∞</inf> controller and with the nonsmooth H<inf>∞</inf> controller. The simulation demonstrates that the two adaptive optics systems achieve approximate control performance, and proves the efficiency of nonsmooth H<inf>∞</inf> control method for the adaptive optics system. (19 refs.)Main Heading: Adaptive opticsControlled terms: Adaptive control systems - Atmospheric thermodynamics - Atmospheric turbulence - Computer simulation - Controllers - Robust control - WavefrontsUncontrolled terms: Adaptive optics systems - Control performance - Hankel singular values - Model reduction - Robust controllers - Simple structures - Simulation - Single input single outputClassification Code: 443.1 Atmospheric Properties - 711 Electromagnetic Waves - 723.5 Computer Applications - 731 Automatic Control Principles and Applications - 731.1 Control Systems - 732.1 Control Equipment

Database: Compendex

Environmental simulation evaluation of SSiC brazed optical mirrors

Liu, Yan1; Ma, Zhen2; Chen, Jian1; Chen, Zhongming1; Liu, Xuejian1; Huang, Zhengren1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2068140; Article number: 928009; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Shanghai Institute of Ceramics, C.A.S, Shanghai, China2 Xi'an Institute of Optics and Precision Mechanics, C.A.S, Xi'an, China

Abstract: Sintered silicon carbide (SSiC) is becoming one of the most important materials for the optical mirrors due to its excellent specific stiffness (E/ρ) and demission stability (λ/α). However, it is difficult to fabricate the monolithic structure SSiC optical mirror with demission of larger than Φ1.5m because of process limitation. Joining of SSiC segments (brazing) provide a good solution to prepare large size mirror optics. However, compared with the uniform properties of the monolithic structure SSiC optical mirror, the brazed mirror is composed of two materials (SSiC segments and brazing material), so the performance of optical grinding and reliability of brazed optical mirrors become the focus. In this paper, the Φ300mm and Φ600mm brazed optical mirrors was used to evaluate the reliability of different conditions. Three kinds of environmental simulation tests, including thermal stability, thermal circle and random vibration were carried out. The evaluation results show that the temperature and vibration has no obvious effects on the surface figure (RMS) of the brazed optical mirrors. © 2014 SPIE. (2 refs.)Main Heading: Optical testingControlled terms: Brazing - Manufacture - Mirrors - Silicon carbide - Sintered carbides - Sintering - Telescopes - Thermodynamic stabilityUncontrolled terms: Environmental simulation - Evaluation results - Monolithic structures - Optical mirror - Random vibrations - Specific stiffness - Surface figure - Thermal circleClassification Code: 536.1 Powder Metallurgy Operations - 537.1 Heat Treatment Processes - 538.1.1 Soldering - 641.1 Thermodynamics - 741.3 Optical Devices and Systems - 804.2 Inorganic Compounds

Database: Compendex

Low-memory-usage and high-speed image wavelet transform

Huang, Ji-Jiang1; Cao, Jian-Zhong1; Bo, Yi1; Chen, Liu2 Source: ICIST 2014 - Proceedings of 2014 4th IEEE International Conference on Information Science and Technology, p 523-526, October 10, 2014; ISBN-13: 9781479948086; DOI: 10.1109/ICIST.2014.6920531; Article number: 6920531; Conference: 2014 4th IEEE International Conference on Information Science and Technology, ICIST 2014, April 26, 2014 - April 28, 2014; Sponsor: Chinese Academy of Engineering; IEEE Beijing Section; The Chinese University of Hong Kong;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 Graduate University of Chinese Academy of Sciences, Beijing, China

Abstract: Discrete wavelet transform (DWT) is being broadly used in processing digital image, but the large requirement of memory and the time delay limit the DWT usage. For instance, when the image is processed in the space, the realtime processing, low power consumption, reduced complexity and low memory consumption are required. Lifting-based DWT is implemented to lessen complexity. And then the coefficients of the lifting filters are turned to be binary and the filters are therefore implemented efficiently without using any multiplier. In this way the frequency of DWT can be improved and the architecture is simplified. When 2-dimensional DWT is carried out, the line-based wavelet transform is able to save memory in a larger sense. The architecture of line-based wavelet can also be executed in a parallel way. Both horizontal transform and vertical transform can be executed at the same time. This paper takes 9/7 wavelet as an example and compares with others its architecture and performance. The advantages of this design include real-time performance improvement, memory reduction and architecture simplification. © 2014 IEEE. (9 refs.)Main Heading: Wavelet transformsControlled terms: Discrete wavelet transforms - Time delayUncontrolled terms: Binary coefficient - Lifting based DWT - Lifting-based wavelet - Line-based - Low-power consumption - Real time performance - Realtime processing - Reduced complexityClassification Code: 713 Electronic Circuits - 731 Automatic Control Principles and Applications - 921.3 Mathematical Transformations

Database: Compendex

Experimental analysis of focal fields in laser scanning fluorescence stereomicroscopy

Yang, Yanlong1; Peng, Tong1; Lei, Ming1; Li, Runze1; Zhou, Xing1; Wu, Di1; Yao, Baoli1; Ye, Tong2 Source: Progress in Biomedical Optics and Imaging - Proceedings of SPIE, v 8949, 2014, Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXI

; ISSN: 16057422; ISBN-13: 9780819498625; DOI: 10.1117/12.2040248; Article number: 89491R; Conference: Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXI, February 3, 2014 - February 6, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi, China2 CU-MUSC Bioengineering Program, Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Charleston, SC 29425, United States

Abstract: Bessel beams have been proved to have the ability to extend the depth of focus in fluorescence microscopy. But the depth discrimination was not investigated thoroughly. Following our previous work2, we investigated focal fields of Bessel-Gauss beams at different scanning angles. We found that the central focusing lines were tilted differently at different scanning angles. This effect manifests the ability of the true perspective view in the fluorescence stereomicroscopy. © 2014 SPIE. (17 refs.)Main Heading: Three dimensionalControlled terms: Bessel functions - Fluorescence - Fluorescence microscopy - Image acquisition - Laser applications - Laser beamsUncontrolled terms: Bessel-Gauss beams - Extended depth of field - Laser scanning - Stereomicroscopy - Three dimensional imaging - Volume imagingClassification Code: 461.9.1 Immunology - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741.1 Light/Optics - 744.8 Laser Beam Interactions - 744.9 Laser Applications - 921 Mathematics

Database: Compendex

Research on polarized scattering of self-organized nanogratings induced by femtosecond laser

Xue, Jun1; Yang, Yong2; Li, Chen2; Li, Dongjuan2 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 4, April 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0432001; Article number: 0432001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 School of Natural and Applied Sciences, Engineering University, Armed Police Force, Xi'an, Shaanxi 710086, China2 States Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China

Abstract: Experiments confirm that the femtosecond laser induced periodic nanogratings in a transparent material represents the novel optical properties. The scattering characteristics of nanogratings and nano-grating array are studied in detail by experiments and finite-difference time-domain (FDTD) respectively. Analysis result shows that scattering characteristics of nanogratings are sensitive to the polarization of the incident laser. For arrays of nanogratings, the scattering intensity in the laser polarization perpendicular to the nanograting is 20000 times larger than that in the laser polarization parallel to the nanograting. Morerover, the scattering intensity is dependent on the incident laser wavelength. The longer the wavelength is, the weaker the scattering intensity will be. The simulation results demonstrate that type II waveguide and the light polarized guide mechanism of nanograting are based on scattering characteristics of nanograting instead of birefringence effect theoretically. (16 refs.)Main Heading: ScatteringControlled terms: Experiments - Finite difference time domain method - Laser optics - Time domain analysis - Ultrashort pulses - WaveguidesUncontrolled terms: Birefringence effects - Finite difference time domains - Laser technique - Nanograting - Polarization scattering - Polarized scattering - Scattering char-acteristics - Transparent materialClassification Code: 711 Electromagnetic Waves - 714.3 Waveguides - 744.1 Lasers, General - 901.3 Engineering Research - 921 Mathematics

Database: Compendex

Design of midwave infrared athermalization optical system with a large focal plane array

Shen, Mande1; Li, Cheng1; Ren, Huanhuan1; Jiang, Qinxiu1; Chen, Liangyi2 Source: Optik, v 125, n 13, p 3085-3087, July 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.12.024;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Wuhan Textile University, Wuhan, Hubei 430073, China2 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an 710119, China

Abstract: Based on the most advanced staring focal plane array which had a format of 640 × 480 and the pixel pitch of 15 μm, a set of all-sphere midwave infrared ahermalization optical system was designed. The working wavelength was in 3-5 μm, the full field of view was 8.58°, the relative aperture was 1/2, the efficient focal length (EFL) was 80 m. The opticalsystem consisted of four lenses with three kinds of material - Ge, ZnSe and Si. All surfaces were sphere, which was easier to process test, making the cost inexpensive, and it could avoid using diffractive surface and aspheric surface. The image quality of the system approaches the diffraction limit in the temperature range -60 °C-180 °C. The design results proved that, the high resolution midwave infrared optical system had compact structure, small volume, high resolution and excellent image quality, meeting the design requirements, so that it could be used for photoelectric detection and tracking system.Main Heading: Optical systemsControlled terms: Diffraction - Germanium - Image quality - Optical designUncontrolled terms: Compact structures - Diffraction limits - Diffractive surfaces - Infrared lens - Infrared optical systems - Mid wave infrared (MWIR) - Photoelectric detection - Temperature rangeClassification Code: 741 Light, Optics and Optical Devices - 804 Chemical Products Generally

Database: Compendex

Vehicle detection based on semantic component analysis

Cui, Guosheng1, 3; Wang, Qi2; Yuan, Yuan1 Source: ACM International Conference Proceeding Series, p 172-176, 2014, ICIMCS 2014 - Proceedings of the 6th International Conference on Internet Multimedia Computing and Service; ISBN-13: 9781450328104; DOI: 10.1145/2632856.2632861; Conference: 6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014, July 10, 2014 - July 12, 2014; Sponsor: National Natural Foundation of China; SIGMM China Chapter; Xiamen University;

Publisher: Association for Computing MachineryAuthor affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China3 University of the Chinese Academy of Sciences, 19A Yuquanlu, Beijing, 100049, China

Abstract: Vehicle detection is a hot topic in trafic monitoring applications. Though many researchers has done a lot work towards this direction, the detection in occluded conditions is rarely explored and it still remains a challenge. In this work, we focus on the occlusion problem in vehicle detection and propose a novel method based on semantic component analysis and scale consideration. Two contributions are claimed in this procedure: 1) Tackling vehicle detection by semantic component detection and synthesis. 2) Addressing the scale variation of vehicles by simple yet effective standard component definition. The experimental results on two typical surveillance videos show that the proposed method can effectively detect the vehicles in the crowded trafic conditions with occlusion. Copyright 2014 ACM. (18 refs.)Main Heading: SemanticsControlled terms: Internet - Network security - Security systemsUncontrolled terms: Deformable part-based models - Monitoring applications - Occlusion - Occlusion problems - Semantic components - Standard components - Surveillance video - Vehicle detectionClassification Code: 723 Computer Software, Data Handling and Applications - 903.2 Information Dissemination - 914.1 Accidents and Accident Prevention

Database: Compendex

Double constrained NMF for hyperspectral unmixing

Lu, Xiaoqiang1; Wu, Hao2; Yuan, Yuan1 Source: IEEE Transactions on Geoscience and Remote Sensing, v 52, n 5, p 2746-2758, May 2014

; ISSN: 01962892; DOI: 10.1109/TGRS.2013.2265322; Article number: 6553069;

Abstract: Given only the collected hyperspectral data, unmixing aims at obtaining the latent constituent materials and their corresponding fractional abundances. Recently, many nonnegative matrix factorization (NMF)-based algorithms have been developed to deal with this issue. Considering that the abundances of most materials may be sparse, the sparseness constraint is intuitively introduced into NMF. Although sparse NMF algorithms have achieved advanced performance in unmixing, the result is still susceptible to unstable decomposition and noise corruption. To reduce the aforementioned drawbacks, the structural information of the data is exploited to guide the unmixing. Since similar pixel spectra often imply similar substance constructions, clustering can explicitly characterize this similarity. Through maintaining the structural information during the unmixing, the resulting fractional abundances by the proposed algorithm can well coincide with the real distributions of constituent materials. Moreover, the additional clustering-based regularization term also lessens the interference of noise to some extent. The experimental results on synthetic and real hyperspectral data both illustrate the superiority of the proposed method compared with other state-of-the-art algorithms. © 1980-2012 IEEE. (47 refs.)Main Heading: AlgorithmsControlled terms: Electrical engineering - GeologyUncontrolled terms: Clustering-based regularization - Constituent materials - Hyperspectral unmixing - Mixed pixel - Nonnegative matrix factorization - Sparseness constraints - State-of-the-art algorithms - Structural informationClassification Code: 481.1 Geology - 709 Electrical Engineering, General - 723 Computer Software, Data Handling and Applications - 921 Mathematics

Database: Compendex

Study of push-broom infrared fiber image transmission system

Zhao, Yi-Yi1, 2; Yang, Jian-Feng1; Yan, Xing-Tao1, 2; Li, Fu1; Xue, Bin1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 2, February 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144302.0222002; Article number: 0222002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: The push-broom infrared remote sensing imaging technology plays an important role in the high-resolution earth observation, but the internal development of infrared imaging technology is baffled by the technical level of long-linear array infrared detector. To achieve high-resolution push-broom infrared imaging, a method by the use of line-plane-switching infrared fiber bundle was proposed. In this method, the linear array end of the imaging fiber bundle was used as a long-linear array infrared detector and the plane array end of the bundle was coupled by a mature small infrared focal plane array with the single fiber corresponding to the pixel of the focal plane. The main problem of the design of the objective lens and coupling lens in the infrared fiber image transmission system was analyzed. And a system with an objective lens and an coupling lens was designed for a kind of fiber bundle which has 4000×6 pixels on its entrance end and has 160×150 pixels on its exit end. The imaging performance of the objective lens and coupling lens were close to the diffraction limits while meeting special requirements of infrared fiber image transmission system. The presented design is a better reference for this kind of fiber image transmission system. The mean transfer function was introduced for evaluating the MTF of the overall optical system, and the simulation results show a good image quality. (15 refs.)Main Heading: FibersControlled terms: Diffraction - Infrared detectors - Infrared imaging - Optical design - Optical instrument lenses - Optical systems - PixelsUncontrolled terms: Fiber bundles - Fiber image transmissions - Imaging fiber bundle - Infrared focal plane arrays - Infrared imaging technology - Infrared remote sensing - Internal development - Objective lensClassification Code: 723.5 Computer Applications - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

Temporal contrast measurement of a single-shot laser pulse by optical pulse replication

Yuan, Suochao1; Gao, Limin1; Li, Dongjian1; Zhao, Juanning1, 2 Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams, v 26, n 5, 2014; Language: Chinese

; ISSN: 10014322; DOI: 10.11884/HPLPB201426.051016; Article number: 051016;

Publisher: Editorial Office of High Power Laser and Particle BeamsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: For the measurement of the time profile and the contrast information of the ultrashort laser pulse, based on the third-order intensity correlation principle, using optical pulse replication, a measurement method is proposed. Theoretical analysis is made about the measurement method. The simulation was done with split-step Fourier and Runge-Kutta methods. By measuring the pulse with pieces of windows and piecing the windows together, the measuring range can be enlarged. Thus a high resolution and large window measurement is achieved. The pre-pulse and main pulse are separated into different windows to avoid the use of gradient attenuator, and provides high-contrast measurement capability. (23 refs.)Main Heading: MeasurementsControlled terms: Runge Kutta methods - Ultrashort pulsesUncontrolled terms: Contrast measurements - Intensity correlation - Measurement methods - Pulse replication - Single-shot - Split-step Fourier - Temporal contrast - Third-orderClassification Code: 744.1 Lasers, General - 921.6 Numerical Methods - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

An optimization model and genetic algorithm solution for automated celestial navigation of ships

Li, Hui1; Lu, Gang2; Wang, Wei3; Wang, An Guo1 Source: Applied Mechanics and Materials, v 548-549, p 1277-1281, 2014, Achievements in Engineering Sciences

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350842; DOI: 10.4028/www.scientific.net/AMM.548-549.1277; Conference: 3rd International Conference on Manufacturing Engineering and Process, ICMEP 2014, April 10, 2014 - April 11, 2014; Sponsor: Carleton University; Science and Engineering Institute; University of Ontario Institute of Technology (UOIT);

Publisher: Trans Tech PublicationsAuthor affiliation: 1 Dept. of Navigation, Dalian Naval Academy, Liaoning province, Dalian 116018, China2 Shandong province, Qingdao 266071, China3 Xi'an Institute of Optics and Precision Mechanics, Shanxi province, Xi'an 710119, China

Abstract: Inclination measurement errors have a significant effect on the positioning accuracy of an automated ship celestial navigation system using the existing theoretical models. To reduce such undesirable effect, we propose a nonlinear least-squares model based on global optimization and provide a genetic algorithm solution using proportional selection, arithmetical crossover, Gaussian mutation, and elitist strategy. The performance of the model and solution is demonstrated by an instance of simulation experiment. The results indicate that the global near-optimal solution of a ship's attitude and position can be obtained with accuracy of arc-second level, and the accuracy is better than that of the existing models by one to two orders of magnitude under the same measurement conditions. © (2014) Trans Tech Publications, Switzerland. (10 refs.)Main Heading: ShipsControlled terms: Algorithms - Automation - Computer simulation - Genetic algorithms - Global optimization - Navigation systems - Star trackersUncontrolled terms: Celestial navigation - Celestial Navigation System - Measurement conditions - Near-optimal solutions - Nonlinear least squares - Optimization modeling - Positioning accuracy - Undesirable effectsClassification Code: 434.4 Waterway Navigation - 671 Naval Architecture - 672 Naval Vessels - 674 Small Craft and Other Marine Craft - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 731 Automatic Control Principles and Applications - 732 Control Devices - 741.3 Optical Devices and Systems - 921 Mathematics - 921.5 Optimization Techniques

Database: Compendex

Image annotation by multiple-instance learning with discriminative feature mapping and selection

Hong, Richang1; Wang, Meng1; Gao, Yue2; Tao, Dacheng3; Li, Xuelong4; Wu, Xindong1, 5 Source: IEEE Transactions on Cybernetics, v 44, n 5, p 669-680, May 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2265601; Article number: 6542696;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Computer and Information, Hefei University of Technology, Hefei 230009, China2 School of Computing, National University of Singapore, 119615 Singapore, Singapore3 Center for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology, Sydney, NSW 2007, Australia4 Center for Optical Imagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China5 Department of Computer Science, University of Vermont, Burlington, VT 05405-0156, United States

Abstract: Multiple-instance learning (MIL) has been widely investigated in image annotation for its capability of exploring region-level visual information of images. Recent studies show that, by performing feature mapping, MIL can be cast to a single-instance learning problem and, thus, can be solved by traditional supervised learning methods. However, the approaches for feature mapping usually overlook the discriminative ability and the noises of the generated features. In this paper, we propose an MIL method with discriminative feature mapping and feature selection, aiming at solving this problem. Our method is able to explore both the positive and negative concept correlations. It can also select the effective features from a large and diverse set of low-level features for each concept under MIL settings. Experimental results and comparison with other methods demonstrate the effectiveness of our approach. © 2013 IEEE. (52 refs.)Main Heading: Feature extractionControlled terms: Image analysis - MappingUncontrolled terms: Concept correlation - Discriminative ability - Discriminative features - Image annotation - Low-level features - Multiple-instance learning - Supervised learning methods - Visual informationClassification Code: 716 Telecommunication; Radar, Radio and Television - 741 Light, Optics and Optical Devices - 902.1 Engineering Graphics

Database: Compendex

Theoretical study on slow light in different structures of optical microfiber knot resonators (OMKRs)

Xu, Yiping1, 2; Ren, Liyong1; Ma, Chengju1, 2; Liang, Jian1 Source: Optik, v 125, n 12, p 2856-2861, June 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.11.056;

Abstract: Based on the light propagation theory of the single-ring optical microfiber knot resonator (OMKR), we further establish the similar theory for OMKRs with a parallel connection structure and that with a serial connection structure, respectively. The relationships of the output and the input light fields in different OMKRs are analyzed. Numerical simulations of the slow-light performances of the OMKRs with single ring, multi-parallel rings and multi-serial rings at the communication wavelength around 1550 nm are given and discussed. Compared with the single-ring OMKR, it is found that a large group time delay with very narrow bandwidth can be obtained in OMKRs with n-ring parallel connection structure, while a broadband group time delay can be achieved in OMKRs with n-ring serial connection structure. © 2014 Elsevier GmbH. All rights reserved. (32 refs.)Main Heading: ResonatorsControlled terms: Electric connectors - Electric inverters - Group delay - Optical fibers - Slow lightUncontrolled terms: Communication wavelengths - Different structure - Micro-fiber knot resonators - Narrow bandwidth - Parallel connections - Propagation theory - Serial connection - Theoretical studyClassification Code: 703.1 Electric Networks - 704.2 Electric Equipment - 706.2 Electric Power Lines and Equipment - 714 Electronic Components and Tubes - 741.1 Light/Optics - 741.1.2 Fiber Optics

Database: Compendex

Robust Hashing with local models for approximate similarity search

Song, Jingkuan1; Yang, Yi1; Li, Xuelong2; Huang, Zi1; Yang, Yang3 Source: IEEE Transactions on Cybernetics, v 44, n 7, p 1225-1236, July 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2289351; Article number: 6714849;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD 4072, Australia2 Center for Optical Imagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, Shaanxi, China3 School of Computing, National University of Singapore, 119077 Singapore, Singapore

Abstract: Similarity search plays an important role in many applications involving high-dimensional data. Due to the known dimensionality curse, the performance of most existing indexing structures degrades quickly as the feature dimensionality increases. Hashing methods, such as locality sensitive hashing (LSH) and its variants, have been widely used to achieve fast approximate similarity search by trading search quality for efficiency. However, most existing hashing methods make use of randomized algorithms to generate hash codes without considering the specific structural information in the data. In this paper, we propose a novel hashing method, namely, robust hashing with local models (RHLM), which learns a set of robust hash functions to map the high-dimensional data points into binary hash codes by effectively utilizing local structural information. In RHLM, for each individual data point in the training dataset, a local hashing model is learned and used to predict the hash codes of its neighboring data points. The local models from all the data points are globally aligned so that an optimal hash code can be assigned to each data point. After obtaining the hash codes of all the training data points, we design a robust method by employing <inf>2,1</inf>-norm minimization on the loss function to learn effective hash functions, which are then used to map each database point into its hash code. Given a query data point, the search process first maps it into the query hash code by the hash functions and then explores the buckets, which have similar hash codes to the query hash code. Extensive experimental results conducted on real-life datasets show that the proposed RHLM outperforms the state-of-the-art methods in terms of search quality and efficiency. © 2013 IEEE. (29 refs.)Main Heading: Hash functionsControlled terms: Image retrieval - Indexing (of information) - Query processingUncontrolled terms: High dimensional data - Indexing structures - Locality sensitive hashing - Randomized Algorithms - Robust hashing - Similarity search - State-of-the-art methods - Structural informationClassification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 903.1 Information Sources and Analysis - 921 Mathematics

Database: Compendex

Road surface condition sensor based on scanning detection of backward power

Xu, Songsong1; Ruan, Chi1; Feng, Lili1 Source: Chinese Optics Letters, v 12, n 5, May 2014

; ISSN: 16717694; DOI: 10.3788/COL201412.050801; Article number: 050801;

Abstract: A method of detecting dry, icy and wet road surface conditions based on scanning detection of single wavelength backward power is proposed in this letter. The detector is used to receive the backward scattered power which changes with the incidence angle. The relationship between backward power and incidence angle is used to find out the effective angle range and distinguish method. Experiment and simulation show that it is feasible to classify these three conditions within incidence angle of 5.3 degree. © 2014 Chinese Optics Letters. (12 refs.)Main Heading: DetectorsControlled terms: Roads and streetsUncontrolled terms: Incidence angles - Road surface condition - Single wavelength - Wet roadClassification Code: 406.2 Roads and Streets - 914 Safety Engineering

Database: Compendex

Methods of fault diagnosis in fiber optic current transducer based on Allan variance

Wang, Lihui1, 2; Chen, Gang3; Ji, Jianfei3; Sun, Jian3; Qian, Jiabin1; Liu, Xixiang1 Source: Mathematical Problems in Engineering, v 2014, 2014

; ISSN: 1024123X, E-ISSN: 15635147; DOI: 10.1155/2014/831075; Article number: 831075;

Publisher: Hindawi Publishing CorporationAuthor affiliation: 1 Southeast University, Key Laboratory of Micro-Inertial Instrument and Advanced Navigation Technology, Ministry of Education, Nanjing 210096, China2 State Key Laboratory of Transient Optics and Technology, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian 710119, China3 Jiangsu Electrical Power Company Research Institute, Nanjing 211103, China

Abstract: To ensure low failure and high reliability of fiber optic current transducers (FOCTs), it is urgent to study methods of condition monitoring and fault diagnosis in FOCT. Faults in FOCT have statistical characteristics. With the analyzing of time domain and frequency domain features in fiber optic current transformers' measurement data, we establish correspondence between the physical characteristics of key components in transformer and data features and then build diagnostic analysis model based on Allan variance. According to the Allan variance calculation results, we can diagnose fiber optic current transformer's health state and realize faults location. Experiment results show that diagnostic methods based on Allan variance are accurate and effective to identify fault features. © 2014 Lihui Wang et al. (13 refs.)Main Heading: Time domain analysisControlled terms: Condition monitoring - Electric fault currents - Electric instrument transformers - Fiber optics - TransducersUncontrolled terms: Current transducer - Diagnostic analysis - Diagnostic methods - Fiber optic current transformer - Frequency domains - High reliability - Physical characteristics - Statistical characteristicsClassification Code: 603 Machine Tools - 704 Electric Components and Equipment - 706 Electric Transmission and Distribution - 706.2 Electric Power Lines and Equipment - 714 Electronic Components and Tubes - 715 Electronic Equipment, General Purpose and Industrial - 741.1.2 Fiber Optics - 921 Mathematics

Database: Compendex

Piecewise linear response based on CMV4000 image sensor

Meng, Yang Yang1; Hu, Xiao Dong1; Yang, Dong Lai1 Source: Applied Mechanics and Materials, v 568-570, p 568-572, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.568;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: With high speed CMOS image sensor CMV4000 produced by CMOSIS company as the object, after the thorough analysis of the piecewise linear response principle and how to extend the dynamic range, using piecewise linear response extends the dynamic range of CMV4000 image sensor. The ideas and methods of using the finite state machine designs piecewise linear response sequence are given, and the function simulation is done for the sequence in the Quartus II 9.0 environment using the Verilog HDL hardware description language. Through the analysis of simulation results, it can satisfy the demands of piecewise linear response sequence. The method is simple and feasible, and can improve the optical dynamic range of CMV4000 image sensor. © (2014) Trans Tech Publications, Switzerland. (7 refs.)Main Heading: Piecewise linear techniquesControlled terms: Computer hardware description languages - Image sensors - Machine designUncontrolled terms: Analysis of simulations - CMOS image sensor - CMV4000 - Dynamic range - Function simulation - Optical dynamics - Piecewise linear - Verilog HDLClassification Code: 601 Mechanical Design - 722 Computer Systems and Equipment - 731.1 Control Systems - 741.3 Optical Devices and Systems

Database: Compendex

FIVQ algorithm for interference hyper-spectral image compression

Wen, Jia1, 2; Ma, Caiwen2; Zhao, Junsuo1 Source: Optics Communications, v 322, p 97-104, July 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.02.016;

Publisher: ElsevierAuthor affiliation: 1 Science and Technology on Integrated Information System Laboratory, Institute of Software, Chinese Academy of Sciences, No. 4 South Fourth Street, Zhong Guan Cun, Beijing 100190, China2 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, No. 17 Xinxi Road Xian Hi-Tech Ind. Devel. Zone, Xian, Shaanxi 710119, China

Abstract: Based on the improved vector quantization (IVQ) algorithm [1] which was proposed in 2012, this paper proposes a further improved vector quantization (FIVQ) algorithm for LASIS (Large Aperture Static Imaging Spectrometer) interference hyper-spectral image compression. To get better image quality, IVQ algorithm takes both the mean values and the VQ indices as the encoding rules. Although IVQ algorithm can improve both the bit rate and the image quality, it still can be further improved in order to get much lower bit rate for the LASIS interference pattern with the special optical characteristics based on the pushing and sweeping in LASIS imaging principle. In the proposed algorithm FIVQ, the neighborhood of the encoding blocks of the interference pattern image, which are using the mean value rules, will be checked whether they have the same mean value as the current processing block. Experiments show the proposed algorithm FIVQ can get lower bit rate compared to that of the IVQ algorithm for the LASIS interference hyper-spectral sequences. © 2014 Elsevier B.V. (13 refs.)Main Heading: AlgorithmsControlled terms: Encoding (symbols) - Image compression - Image quality - Spectroscopy - Vector quantizationUncontrolled terms: Arithmetic Coding - Current processing - Encoding rules - Hyper-spectral images - Imaging principle - Interference patterns - LBG algorithm - Optical characteristicsClassification Code: 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 741 Light, Optics and Optical Devices - 801 Chemistry - 921 Mathematics

Database: Compendex

The pulsed all fiber laser application in the high-resolution 3D imaging LIDAR system

Gao, Cunxiao1; Zhu, Shaolan1; Niu, Linquan1; Feng, Li1; He, Haodong1; Cao, Zongying1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9135, 2014, Laser Sources and Applications II

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410839; DOI: 10.1117/12.2048275; Article number: 91351M; Conference: Laser Sources and Applications II, April 14, 2014 - April 17, 2014; Sponsor: Brussels Photonics Team (B-PHOT); Brussels-Capital Region; Fonds Wetenschappelijk Onderzoek (FWO); The Society of Photo-Optical Instrumentation Engineers (SPIE); Ville de Bruxelles;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics (China) 1State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: An all fiber laser with master-oscillator-power-amplifier (MOPA) configuration at 1064nm/1550nm for the high-resolution three-dimensional (3D) imaging light detection and ranging (LIDAR) system was reported. The pulsewidth and the repetition frequency could be arbitrarily tuned 1ns&sim;10ns and 10KHz&sim;1MHz, and the peak power exceeded 100kW could be obtained with the laser. Using this all fiber laser in the high-resolution 3D imaging LIDAR system, the image resolution of 1024×1024 and the distance precision of ±1.5 cm was obtained at the imaging distance of 1km. © 2014 SPIE. (5 refs.)Main Heading: Imaging systemsControlled terms: Fiber amplifiers - Fiber lasers - Image resolution - Optical radar - Power amplifiersUncontrolled terms: 3D imaging - All-fiber lasers - High resolution - Imaging distances - Light detection and ranging systems - Pulsewidths - Repetition frequency - Three dimensional (3-D) imagingClassification Code: 713.1 Amplifiers - 741 Light, Optics and Optical Devices - 742 Cameras and Photography - 746 Imaging Techniques

Database: Compendex

Line-plane-switching infrared fiber imaging bundle

Zhan, Huan1, 2; Yan, Xingtao1, 2; Zhang, Aidong1; Li, Fu1; Yang, Jianfeng1; Lin, Aoxiang1 Source: Optics InfoBase Conference Papers, 2014, CLEO: Science and Innovations, CLEO_SI 2014; E-ISSN: 21622701; ISBN-13: 9781557529992; Conference: CLEO: Science and Innovations, CLEO_SI 2014, June 8, 2014 - June 13, 2014;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an 710119, China2 Graduate School of Chinese Academy of Sciences (CAS), Beijing 100049, China

Abstract: Using line-plane-switching infrared fiber imaging bundle made from As<inf>2</inf>S<inf>3</inf> glass fibers with core of 40 μm, clad of 45 μm, and error of 1% in diameter, we demonstrated push-broom infrared sensing imaging. © 2014 OSA. (5 refs.)Uncontrolled terms: Imaging bundles - Infrared fibers - Infrared sensing

Database: Compendex

Green, cubic Y<inf>2</inf>O<inf>3</inf>: Tb3+ nanospheres: Synthesis and photoluminescence property

Miao, H.1, 2; Hu, X.1, 2; Sun, X.1; Wang, Z.1; Sun, Q.1; Wu, H.1; Zhang, D.1, 2; Bai, J.1, 2; Hou, X.1, 3 Source: Technical Proceedings of the 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014, v 1, p 160-163, 2014, Technical Proceedings of the 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014; ISBN-13: 9781482258264; Conference: Nanotechnology 2014: Graphene, CNTs, Particles, Films and Composites - 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014, June 15, 2014 - June 18, 2014; Sponsor: ACCT Canada; Aerojet Rocketdyne; American University in Cairo; Angel Capital Association; Angel Venture Forum; et al.;

Publisher: Nano Science and Technology InstituteAuthor affiliation: 1 School of Physics, Northwest University, Xi'an 710069, China2 Natl. Photoelectric Technol. and Funct. Mat. and Appl. of Sci. and Technol. Intl. Cooperation Base, Northwest University, Xi'an 710069, China3 State Key Laboratory of Transient Optics and Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710068, China

Abstract: In this study, Tb3+-doped Y<inf>2</inf>O<inf>3</inf> green nanospheres were prepared via the simple, cost-effective urea homogeneous precipitation method without additives. The specimens annealed above 800° C are well matched with the cubic phase (JCPDS, 41-1105), and the crystallinity increases with raising the annealing temperature. All the as prepared samples consist of well separated spherical particles with diameter size varying from 200nm to 700nm. Obviously, the average size of the separated spherical particles decreases by the raising of the annealing temperature while the photoluminescence intensity excited by either 275nm or 300nm increases. (7 refs.)Main Heading: Nanocomposite filmsControlled terms: Annealing - Nanospheres - Nanotechnology - Photoluminescence - Precipitation (chemical) - Synthesis (chemical) - UreaUncontrolled terms: Annealing temperatures - Average size - Crystallinities - Cubic phase - Photoluminescence intensities - Photoluminescence properties - Spherical particle - Urea homogeneous precipitationsClassification Code: 537.1 Heat Treatment Processes - 712.1 Semiconducting Materials - 741.1 Light/Optics - 761 Nanotechnology - 802.2 Chemical Reactions - 802.3 Chemical Operations - 804.1 Organic Compounds - 933 Solid State Physics

Database: Compendex

Design of large aperture off-axis middle infrared continuous zoom lens

Wang, Da-Bao1; Jiang, Kai2; Zhao, Shi-Min3; Hao, Wei2; Jiang, Bo2; Zhou, Si-Zhong2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 6, June 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144306.0622004; Article number: 0622004;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Beijing Institute of Spacecraft System Engineering, Beijing 100094, China2 The Photoelectric Track and Measurement Technology Research Department, Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an 710119, China3 Taiyuan Satellite Launching Center, Taiyuan 030027, China

Abstract: On the basics of a cool 320×240 detector with staring focal plane array, a off-axis catadioptric middle infrared continuous zoom system with large aperture and long focal length is designed. The optical system was divided into two segments. First an off-axis aspheric non-power system as the front system was designed, then the continuous zoom lens which matched with the non-power system as the back system was designed. Because of the material constraint, the refractive zoom system can't realize large aperture. Coaxal catadioptric zoom system has great block ratio. And three mirrors zoom system can't achieve cold shield efficiency 100%. The off-axis catadioptric zoom system can account for forenamed limitation. The system worked at 3.7~4.8 μm has achieved the zoom of 250 mm to 2 000 mm and F number of 4. This system can offer a high resolution and excellent images, and its cold shield efficiency is 100%. The system satisfies the design requirements. (15 refs.)Main Heading: Optical systemsControlled terms: Imaging systems - Optical designUncontrolled terms: Continuous zooms - Large aperture - Middle infrared - Off-axis - UnobstructedClassification Code: 741 Light, Optics and Optical Devices - 746 Imaging Techniques

Database: Compendex

Linearization of coupled pointing and tracking dynamical equations

Luo, Cui Hua1, 2, 3; Qi, Hai Feng3; Ma, Cai Wen3 Source: Advanced Materials Research, v 971-973, p 1637-1642, 2014, New Technologies for Engineering Research and Design in Industry

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038351412; DOI: 10.4028/www.scientific.net/AMR.971-973.1637; Conference: 2014 International Conference on Mechatronics and Intelligent Materials, MIM 2014, May 18, 2014 - May 19, 2014; Sponsor: CEIS; IFST; National Chin-Yi University of Technology; Scientific.Net;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Dept. Electrical and Information Engineering, Southwest University for Nationalities, Chengdu, 610041, China2 Dept. Opt-electronicTracking and Measurement Technology, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, 710119,, China3 University of Chinese Academy of Sciences, Beijing, 100038, China

Abstract: Cooperative pointing and tracking is one important characteristic of deep space intersatellite laser communication, so that the dynamic mathematical model is complicated nonlinearity and coupling. The contribution of this paper is to substitute the time-domain error transfer function of state equations and to linearize the state space for the sake of physical realization easily in terms of previous authors' work. The method applied is state feedback and coordinate transformation in nonlinear field, the calculated result is demonstrated that differential equations modeled can be transferred into canonical controllable form and realized physically. © (2014) Trans Tech Publications, Switzerland. (8 refs.)Main Heading: Control nonlinearitiesControlled terms: Controllability - Differential equations - Equations of state - Linearization - Mathematical transformations - Optical links - State feedback - Transfer functionsUncontrolled terms: Co-ordinate transformation - Dynamic mathematical model - Dynamical equation - Inter-satellite laser communications - Nonlinearity - Physical realization - Pointing and tracking - Time-domain errorClassification Code: 717.1 Optical Communication Systems - 731.1 Control Systems - 921 Mathematics

Database: Compendex

LED-based digital holographic microscopy with slightly off-axis interferometry

Guo, Rongli1, 2; Yao, Baoli1; Min, Junwei1; Zhou, Meiling1; Yu, Xianghua1; Lei, Ming1; Yan, Shaohui1; Yang, Yanlong1; Dan, Dan1 Source: Journal of Optics (United Kingdom), v 16, n 12, December 1, 2014

; ISSN: 20408978, E-ISSN: 20408986; DOI: 10.1088/2040-8978/16/12/125408; Article number: 125408;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 Xi'an Technological University, Xi'an, China

Abstract: An LED illuminated Linnik-type digital holographic microscope (DHM) for high-quality phase imaging is presented by the adoption of slightly off-axis two-step blind-phase-shifting interferometry (TB-PSI). Slightly off-axis interferometry lowers the requirement on the angle between the object and the reference waves as well as the requirement on the resolving power of the charge-coupled device (CCD) camera. In addition, the apparatus is cost-effective and offers ease of alignment. The phase-shifting DHM is simply implemented by mechanically moving the reference mirror while disposing of a precise phase modulator such as a piezoelectric transducer (PZT). The phase shift between the two interferograms is extracted by Fourier transformation analysis, and then the phase image is reconstructed. The performance of the TB-PSI used in the scheme is analyzed. The phase imaging for nanostructured specimens is conducted, and the results demonstrate the feasibility of the scheme. The phase noise is reduced by 73% when compared to the result obtained with coherent illumination. (35 refs.)Main Heading: Holographic interferometryControlled terms: Charge coupled devices - Computer generated holography - Cost effectiveness - Fourier transforms - Microscopic examination - Phase measurement - Phase shift - Phase shiftersUncontrolled terms: Coherent illumination - Digital holographic microscopy - Digital holography - Fourier transformations - Interference microscopy - Phase shifting Interferometry - Piezoelectric transducers (PZT) - Reference mirrorsClassification Code: 703.1 Electric Networks - 714.2 Semiconductor Devices and Integrated Circuits - 723.5 Computer Applications - 746 Imaging Techniques - 912.3 Operations Research - 921.3 Mathematical Transformations - 941.4 Optical Variables Measurements - 942.2 Electric Variables Measurements

Database: Compendex

Preparation of the oxyfluoride glass with high 3 laser induced damage threshold

Hou, Chaoqi1, 2; Wang, Pengfei1; Li, Weinan1; Guo, Haitao1; Fu, Lili2; Qiao, Zebang1; Lu, Min1; Wei, Wei1; Peng, Bo1 Source: Optics and Laser Technology, v 56, p 88-91, 2014

; ISSN: 00303992; DOI: 10.1016/j.optlastec.2013.06.015;

Publisher: Elsevier LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Procession Mechanics, Chinese Academy of Science (CAS), Xi'an 710119, China2 Graduate College of Chinese Academy of Science, Beijing 100049, China

Abstract: An oxyfluoride glass with good thermal stability (ΔT=313.72 C), high transmittance and excellent 3ω laser induced damage threshold (LIDT) was prepared by a high temperature melting technique. The oxyfluoride glass has an optical transmittance as high as 91.2% (without AR coatings) at 351 nm and the transmission is stable in the successive laser shots. Its 3ω LIDT is higher than that of fused silica, and the corresponding mechanism has been discussed through SEM microstructure and damage morphology observation. This novel oxyfluoride glass makes itself a promising candidate material used in 3ω high power laser system. © 2013 Published by Elsevier Ltd. (15 refs.)Main Heading: Laser damageControlled terms: Glass - High power lasers - Materials - Optical materialsUncontrolled terms: AR coatings - Candidate materials - Damage morphology - High transmittance - High-power laser systems - High-temperature melting - Laser induced damage thresholds - Oxy-fluoride glassClassification Code: 741.3 Optical Devices and Systems - 744.1 Lasers, General - 744.8 Laser Beam Interactions - 812.3 Glass - 951 Materials Science

Database: Compendex

Reconstructing signals via stochastic resonance generated by photorefractive two-wave mixing bistability

Cao, Guangzhan1; Liu, Hongjun1; Li, Xuefeng2; Huang, Nan1; Sun, Qibing1 Source: Optics Express, v 22, n 4, p 4214-4223, February 24, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.004214;

Publisher: Optical Society of AmericaAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, 710119, China2 School of Science, Xi'An University of Post and Telecommunications, Xi'an, 710121, China

Abstract: Stochastic resonance is theoretically investigated in an optical bistable system, which consists of a unidirectional ring cavity and a photorefractive two-wave mixer. It is found that the output properties of stochastic resonance are mainly determined by the applied noise, the crystal length and the applied electric field. The influences of these parameters on the stochastic resonance are also numerically analyzed via cross-correlation, which offers general guidelines for the optimization of recovering noisehidden signals. A cross-correlation gain of 4 is obtained by optimizing these parameters. This provides a general method for reconstructing signals in nonlinear communications systems. © 2014 Optical Society of America. (25 refs.)Main Heading: Magnetic resonanceControlled terms: Circuit resonance - Electric fields - Optimization - PhotoreactivityUncontrolled terms: Bistable system - Communications systems - Cross correlations - Output property - Photo-refractive - Reconstructing Signals - Stochastic resonances - Unidirectional ring cavityClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 701.2 Magnetism: Basic Concepts and Phenomena - 703.1.1 Electric Network Analysis - 741.1 Light/Optics - 921.5 Optimization Techniques

Database: Compendex

A general approach for fabrication of nitrogen-doped graphene sheets and its application in supercapacitors

Wang, Dewei1; Min, Yonggang1; Yu, Youhai1; Peng, Bo1 Source: Journal of Colloid and Interface Science, v 417, p 270-277, March 1, 2014

; ISSN: 00219797, E-ISSN: 10957103; DOI: 10.1016/j.jcis.2013.11.021;

Publisher: Academic Press Inc.Author affiliation: 1 Institute of Advanced Materials, State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: In this paper, a general and efficient strategy has been developed to produce nitrogen-doped graphene sheets (NGs) based on hard and soft acids and bases (HSAB) theory. Under hydrothermal conditions, any salt with amphiprotic character have a strong tendency to hydrolysis, it is possible to provide reducing agent and nitrogen source simultaneously. It is worth noting that, NGs can be prepared under hydrothermal conditions by using some common ammonium salts with hard acid-soft base pairs as nitrogen-doping agents. The morphology, structure and composition of the as-prepared NGs were studied in detail. The results demonstrated that large amount of nitrogen was incorporated into the nanocarbon frameworks at the same time as the graphene oxide (GO) sheets were reduced. The electrochemical behavior of the synthesized NGs as supercapacitor electrodes was evaluated in a symmetric two-electrode cell configuration with 1M H<inf>2</inf>SO<inf>4</inf> as the electrolytes. It was found that the nitrogen groups making the as-prepared NGs exhibited remarkably enhanced electrochemical performance when used as electrode materials in supercapacitors. The supercapacitor based on the NGs exhibited a high specific capacitance of 242Fg-1 at a current density of 1Ag-1, and remains a relatively high capacitance even at a high current density. This work will put forward to understand and optimize heteroatom-doped graphene in energy storage systems. © 2013 Elsevier Inc. (48 refs.)Main Heading: Electrolytic capacitorsControlled terms: Doping (additives) - Graphene - NitrogenUncontrolled terms: Doped - Electrochemical behaviors - Electrochemical performance - Graphene oxides - High specific capacitances - Hydrothermal conditions - Super capacitor - Supercapacitor electrodesClassification Code: 801 Chemistry - 801.4.1 Electrochemistry - 804 Chemical Products Generally

Database: Compendex

Design of unobscured three-mirror optical system by applying vector wavefront aberration theory

Zou, Gangyi1; Fan, Xuewu1; Pang, Zhihai1; Feng, Liangjie1; Ren, Guorui1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 2, p 569-573, February 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The traditional unobscured three-mirror optical system is an intrinsically rotationally symmetric optical system with an offset aperture stop, a biased input field, or both of them, so off-axis sections of rotationally symmetric aspheric parent surface are ineluctable. Using the conclusion of vector wavefront aberration theory, a new unobscured three-mirror system by tilted the rotationally symmetric aspheric mirror was presented. The design reason and step of this system was analyzed, and then a system with effective focal length of 1 000 mm, field of view of 10° ×20° and F -number 10 was designed. The volume of system (Length×Wide×Height) less than 350 mm×350 mm×120 mm and image qualities of the example are near diffraction limit. Compared with other unobscured three-mirror system, the most prominent advantage of this system is that using tilted rotationally symmetric aspheric mirror to achieve unobscured style, thus reducing cost of the system. (10 refs.)Main Heading: Optical systemsControlled terms: Aberrations - Aspherics - Diffraction - Mirrors - Optical design - Vector spacesUncontrolled terms: Aspheric mirrors - Diffraction limits - Effective focal lengths - Field of views - Reducing costs - Reflective systems - Space optical - Wavefront aberrationsClassification Code: 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Monte carlo simulation of multifocal stochastic scanning system

Liu, Lixin1; Qian, Jia2; Li, Yahui1; Peng, Xiao3; Yin, Jun3 Source: Journal of Innovative Optical Health Sciences, v 7, n 1, 2014

; ISSN: 17935458, E-ISSN: 17937205; DOI: 10.1142/S1793545813500545; Article number: 1350054;

Publisher: World Scientific Publishing Co. Pte. LtdAuthor affiliation: 1 School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China2 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China

Abstract: Multifocal multiphoton microscopy (MMM) has greatly improved the utilization of excitation light and imaging speed due to parallel multiphoton excitation of the samples and simultaneous detection of the signals, which allows it to perform three-dimensional fast fluorescence imaging. Stochastic scanning can provide continuous, uniform and high-speed excitation of the sample, which makes it a suitable scanning scheme for MMM. In this paper, the graphical programming language-LabVIEW is used to achieve stochastic scanning of the two-dimensional galvo scanners by using white noise signals to control the x and y mirrors independently. Moreover, the stochastic scanning process is simulated by using Monte Carlo method. Our results show that MMM can avoid oversampling or subsampling in the scanning area and meet the requirements of uniform sampling by stochastically scanning the individual units of the N × N foci array. Therefore, continuous and uniform scanning in the whole field of view is implemented. © 2014 The Authors. (15 refs.)Main Heading: Monte Carlo methodsControlled terms: Multiphoton processes - Scanning - Stochastic systems - White noiseUncontrolled terms: Excitation light - Fluorescence imaging - Galvo scanners - Graphical programming - Multi-photon microscopy - Multiphoton excitation - Simultaneous detection - Uniform samplingClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 922.2 Mathematical Statistics - 961 Systems Science

Database: Compendex

Efficient optimization of super-oscillatory lens and transfer function analysis in confocal scanning microscopy

Liu, Tao1, 2; Liu, Jian1; Zhang, He1; Tan, Jiubin1 Source: Optics Communications, v 319, p 31-35, May 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2013.12.054;

Publisher: ElsevierAuthor affiliation: 1 Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China2 Institute of Precision Engineering, Xi'An Jiaotong University, Xi'an 710049, China

Abstract: Super-oscillatory lens (SOL) provides a promising way to achieve subwavelength focusing in the regime of far-field optics and realize super-resolution imaging in confocal scanning microscopy (CSM). Both binary amplitude and phase SOLs are designed with an efficient optimization method using genetic algorithm and fast Hankel transform algorithm either in oil immersion medium or in air. A much brighter hotspot is readily focused by a phase SOL compared with the amplitude counterpart, e.g., 5.8 times as bright as the latter. To fundamentally interpret the super-resolution imaging mechanism by SOL in CSM, transfer function analysis is conducted compared with basic confocal imaging. The coherent transfer function (CTF) is derived and numerically calculated. The extension of the cutoff frequency and the remarkable enhancement of the magnitude of CTF in the high frequency passband account for super-resolution imaging by SOL in CSM; however, the limited extension of the frequency domain also implies that the attainable resolution is physically limited. © 2014 Published by Elsevier B.V. (23 refs.)Main Heading: Transfer functionsControlled terms: Confocal microscopy - Cutoff frequency - Image reconstruction - Optical resolving power - SolsUncontrolled terms: Binary optics - Coherent transfer functions - Confocal scanning microscopy - Optimization method - Sub-wavelength focusing - Super resolution - Super resolution imaging - Transfer function analysisClassification Code: 703.1 Electric Networks - 741 Light, Optics and Optical Devices - 804 Chemical Products Generally

Database: Compendex

Fuzzy bag of words for social image description

Li, Yanshan1, 2, 3; Liu, Weiming2; Huang, Qinghua1; Li, Xuelong4 Source: Multimedia Tools and Applications, June 15, 2014

; ISSN: 13807501, E-ISSN: 15737721; DOI: 10.1007/s11042-014-2138-4 Article in PressAuthor affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou, 510640, China2 School of Civil Engineering and Transportation, South China University of Technology, Guangzhou, 510640, China3 Shenzhen University, Shenzhen, 518060, China4 The Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi, 710119, China

Abstract: Rapid growth of social media resources brings huge challenges and opportunities for image description technologies. The performance of image description method directly affects the accuracy of image retrieval, image annotation and image recognition. Bag of Words (BoW) as an efficient approach to describing the images has been attracting more and more attention. However, in traditional BoW, the maps between the words in the codebook and the features extracted from the images are actually ambiguous. As the Fuzzy Sets Theory (FST) is a powerful means for dealing with uncertainty efficiently, we utilize the FST to solve the problem caused by the ambiguity between the features and words. Accordingly, we propose a new type of BoW named as FBoW to describe images based on FST. Firstly, the features are extracted from the images. Secondly, k-means is utilized to learn the codebook. Thirdly, a fuzzy membership function is designed to measure the similarity between the features and words. The optimal parameters of the fuzzy membership function are obtained by using a Genetic Algorithm (GA). The histogram is generated by adding up the fuzzy membership values of each word to describe the images. The experimental results show that the proposed FBoW outperforms traditional BoW for social image description. © 2014 Springer Science+Business Media New York. (36 refs.)Main Heading: Image retrievalControlled terms: Fuzzy sets - Genetic algorithms - Image processing - Image recognitionUncontrolled terms: Fuzzy membership function - Fuzzy membership values - Fuzzy sets theory - Image annotation - Image descriptions - Optimal parameter - Rapid growth - Social imagesClassification Code: 716 Telecommunication; Radar, Radio and Television - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Diode-pumped continuous wave and passively qswitched tm, mg: Litao3 lasers

Feng, T.1; Li, T.1; Zhao, S.1; Li, Q.1; Yang, K.1; Zhao, J.1; Qiao, W.1; Hang, Y.3; Zhang, P.3; Wang, Y.4; Xu, J.2 Source: Optics Express, v 22, n 4, p 3818-3823, February 24, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.003818;

Publisher: Optical Society of AmericaAuthor affiliation: 1 School of Information Science and Engineering, Shandong University, Jinan, Shandong 250100, China2 Key Laboratory for Laser Plasmas (Ministry of Education) and, Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China3 Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800, China4 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We have demonstrated the continuous wave and passively Qswitched Tm, Mg: LiTao<inf>3</inf> lasers for the first time. In continuous wave (CW) regime, a maximum CW output power of 1.03 W at 1952 nm was obtained, giving a slope efficiency of 9.5% and a beam quality M2 = 2.2. Inpassive Q-switching regime, a single walled carbon nanotube (SWCNT) was employed as saturable absorber (SA). The Tm,Mg:LiTao<inf>3</inf> laser has yielded a pulse of 560 ns under repetition rate of 34.2 kHz at 1926 nm, corresponding to a single pulse energy of 10.1 μJ. The results indicate a promising potential of nonlinear crystals in the applications for laser host materials. © 2014 Optical Society of America. (17 refs.)Main Heading: Pumping (laser)Controlled terms: Q switched lasers - Saturable absorbersUncontrolled terms: Continuous Wave - Continuous waves - Laser host materials - Nonlinear crystals - Passively Q-switched - Single pulse energy - Singlewalled carbon nanotube (SWCNT) - Slope efficienciesClassification Code: 744.1 Lasers, General

Database: Compendex

Improved non-uniformity correction algorithm based on integration time Calibration for IRFPA

Leng, Han-Bing1; Zhou, Zuo-Feng1; Yi, Bo1; Zhang, Jian1; Yan, A-Qi1; Wang, Hao1; Cao, Jian-Zhong1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 1, January 2014

; ISSN: 10044213; DOI: 10.3788/gzxb20144301.0110002; Article number: 0110002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: The infrared image quality and temperature resolution is degraded significantly by the non-uniformity response of infrared focal pattern array. Calibration-based and scene-based non-uniformity correction algorithms provide feasible way to handle this problem. Due to its simplicity and accuracy, traditional blackbody calibration-based non-uniformity correction method is widely used but with the disadvantage of highly dependence on the existence of blackbody and its temperature control equipment to provide uniform irradiances. In this paper, an improved two-level non-uniformity correction algorithm based on integration time calibration was proposed. Given the irradiance, the different response data is first obtained through integration time variation. Then the least square method is used to estimate the initial gain coefficients and bias coefficients for two point correction algorithm. Finally, the one point correction coefficients are estimated throuth two point correction of different response data. Experimental results show that the proposed algorithm has the merits of low complexity, high precision, excellent non-uniformity correction performance, and can easily be integrated into hardware platform. (16 refs.)Main Heading: AlgorithmsControlled terms: Calibration - Infrared imaging - Integration - Least squares approximationsUncontrolled terms: Correction coefficients - Infrared focal plane arrays - Integration time - Least Square - Least square methods - Nonuniformity correction - Temperature resolution - Two-point correctionClassification Code: 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 941 Acoustical and Optical Measuring Instruments - 921 Mathematics - 746 Imaging Techniques - 723 Computer Software, Data Handling and Applications

Database: Compendex

Investigations of switchable fiber soliton laser mode-locked by carbon nanotubes

Han, Dongdong1; Zeng, Chao1 Source: Optics Communications, v 319, p 25-30, May 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.01.002;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We have numerically and experimentally investigated a switchable erbium-doped fiber (EDF) laser mode-locked by single-walled carbon nanotubes for the first time to our best knowledge. Depending on the pump power, the central wavelength of the mode-locked pulse can be switched from about 1531 to 1557 nm. The formation and evolution of the switchable soliton operation are investigated numerically by solving the extended nonlinear Schro&die;dinger equation with the appropriate gain profile. Numerical results demonstrate that the switchable mode-locking operation is attributed to the variation of the gain spectrum of EDF, agreeing well with the experimental observations. © 2014 Elsevier B.V. (72 refs.)Main Heading: Locks (fasteners)Controlled terms: Fiber lasers - Laser modes - Nanotubes - Nonlinear equations - Optical pumping - Single-walled carbon nanotubes (SWCN) - SolitonsUncontrolled terms: Central wavelength - Dinger equation - Erbium doped fiber laser - Formation and evolutions - Mode-locked pulse - Numerical results - Soliton laser - SwitchableClassification Code: 921.1 Algebra - 761 Nanotechnology - 744.4 Solid State Lasers - 744.1 Lasers, General - 741.1.2 Fiber Optics - 741.1 Light/Optics - 601.3 Mechanisms

Database: Compendex

Passively Q-switched Nd:YAG laser with single-walled carbon nanotube in heavy water

Wang, Yonggang1, 2; Wang, Yishan1; Zhang, Xiaojun2; Wen, Qiao2 Source: Optics Communications, v 321, p 172-175, June 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.01.067;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China2 Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Ministry of Education and Guangdong Province, Shenzhen, China

Abstract: Carbon nanotubes in heavy water (deuteroxide, D<inf>2</inf>O) dispersion was fabricated and used as absorber in Q-switched Nd:YVO<inf>4</inf> laser for the first time to the best of our knowledge. Such liquid absorber has the virtues of good optical transparency, high heat dissipation and non contact damage. The shortest pulse width of the Q-switched laser is 709 ns, corresponding to 80 kHz repetition rate. The maximum output power of passively Q-switched laser is 214 mW. © 2014 Elsevier B.V. (10 refs.)Main Heading: Neodymium lasersControlled terms: Carbon nanotubes - Heavy water - Q switching - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Absorber - Maximum output power - Optical transparency - Passively Q-switched - Passively Q-switched lasers - Pulsewidths - Q-switches - Repetition rateClassification Code: 744.4 Solid State Lasers - 744.8 Laser Beam Interactions - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Picosecond passively mode-locked laser of 532 nm by reflective carbon nanotube

Cai, Wei1; Peng, Qianqian1; Hou, Wei1; Liu, Jie1, 2; Wang, Yonggang3 Source: Optics and Laser Technology, v 58, p 194-196, June 2014

; ISSN: 00303992; DOI: 10.1016/j.optlastec.2013.12.003;

Publisher: Elsevier LtdAuthor affiliation: 1 Shandong Provincial Key Laboratory of Optics and Photonic Device, College of Physics and Electronics, Shandong Normal University, Jinan 250014, China2 State Key Laboratory of Crystal Material, Shandong University, Jinan 250100, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: By using reflective single-walled carbon nanotube as the saturable absorber, passively continuous-wave mode-locked of Nd:YVO<inf>4</inf>/KTP green laser was realized for the first time. The 532 nm mode-locked pulse width was estimated to be approximately 7.1 ps. The maximum average output power of 456 mW at 532 nm was obtained at a pump power of 7.35 W, corresponding to the repetition rate of 87.14 MHz. The single pulse energy and peak power were 5.23 nJ and 0.74 kW, respectively. © 2013 Elsevier Ltd. (21 refs.)Main Heading: Locks (fasteners)Controlled terms: Mode-locked fiber lasers - Passive mode locking - Q switched lasers - Saturable absorbers - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Average output power - Continuous waves - Green laser - Mode-locked pulse - Passively mode-locked - Passively mode-locked lasers - Reflective single-walled carbon nanotube absorber - Single pulse energyClassification Code: 601.3 Mechanisms - 744.1 Lasers, General - 761 Nanotechnology

Database: Compendex

Reconstruction of compressive spectral imaging system of a FISTA algorithm-based coded aperture

Sun, Nian1, 2; Hu, Bingliang1; Wang, Shuang1; Sun, Lang1; Wang, Zhengjie1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 1, p 238-242, January 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Laboratory of Spectral Imaging Technique, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: A compression and reconstruction solution based on coded aperture was proposed. In this system, the 3D spatial-spectral information about a scene of interest was coded by a random binary element pattern which was achieved by Digital Micro-Mirror Device (DMD), and the processing was snapshot. As a result the 3D information was encoded into a 2D representation. In decoding, a Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) was proposed on the basis of the Two-Step Iterative Shrinkage-Thresholding (TwIST) algorithm. The method developed in this paper did not require more than one gradient evaluation at each iteration, but just an additional point was smartly chosen and easy to compute. The experiments show that the reconstruction performance is much better than TwIST and GPSR both in spatial dimension and spectral dimension. (9 refs.)Main Heading: Iterative decodingControlled terms: Algorithms - Data compression - Image reconstruction - Shrinkage - Spectroscopy - Three dimensionalUncontrolled terms: Coded apertures - Digital micro-mirror device - DMD - Iterative shrinkage-thresholding algorithms - Spatial dimension - Spectral dimensions - Spectral image reconstruction - Spectral imaging systemClassification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 801 Chemistry - 921 Mathematics - 921.6 Numerical Methods - 951 Materials Science

Database: Compendex

Automatic white balance algorithm of airborne camera

Guo, Huinan1; Liu, Qing1; Yang, Lei1; Wang, Hua1; Zhao, Xiao Dong1; Ren, Long1 Source: Applied Mechanics and Materials, v 668-669, p 1050-1054, 2014

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038353126; DOI: 10.4028/www.scientific.net/AMM.668-669.1050; Conference: 3rd Asian Pacific Conference on Mechanical Components and Control Engineering, ICMCCE 2014, September 20, 2014 - September 21, 2014; Sponsor: Nankai University;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, No.17, Xinxi Road, Gaoxin District, Xian; Shaanxi, China

Abstract: Automatic white balance algorithm (AWB) is significant for color temperature restoration of digital imaging system. According to the limitations and disadvantages of existing traditional white balance methods, in this paper a new AWB algorithm for airborne camera is proposed. Using RGB and histogram information divide the input image into different color character regions; according to the color richness level, adopt different white balance algorithms to achieve chromatic aberration adjustment. Experiment results show the effectiveness of the proposed AWB algorithm for airborne camera. © (2014) Trans Tech Publications, Switzerland. (9 refs.)Main Heading: AlgorithmsControlled terms: Aberrations - Cameras - Color - Computer visionUncontrolled terms: Airborne cameras - Automatic white balance - Chromatic aberration - Color temperatures - Digital imaging system - Histogram information - Input image - White balanceClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 742.2 Photographic Equipment - 921 Mathematics

Database: Compendex

Investigation on the factors to influence terahertz absorption spectrum

Fan, Wen-Hui1 Source: International Symposium on Ultrafast Phenomena and Terahertz Waves, ISUPTW 2014, October 13, 2014; Conference: International Symposium on Ultrafast Phenomena and Terahertz Waves, ISUPTW 2014, October 13, 2014 - October 14, 2014; Sponsor: University of Shanghai;

Database: Compendex

Drag reduction in turbulent channel flow using bidirectional wavy Lorentz force

Huang, LePing1, 2; Choi, KwingSo3; Fan, BaoChun2; Chen, YaoHui2 Source: Science China: Physics, Mechanics and Astronomy, v 57, n 11, p 2133-2140, 2014

; ISSN: 16747348; DOI: 10.1007/s11433-014-5416-2;

Publisher: Science in China PressAuthor affiliation: 1 Xian Aerospace Propulsion Institute, Xian, China2 Science and Technology on Transient Physics Laboratory, Nanjing University of Science & Technology, Nanjing, China3 Faculty of Engineering, University of Nottingham, Nottingham, United Kingdom

Abstract: Turbulent control and drag reduction in a channel flow via a bidirectional traveling wave induced by spanwise oscillating Lorentz force have been investigated in the paper. The results based on the direct numerical simulation (DNS) indicate that the bidirectional wavy Lorentz force with appropriate control parameters can result in a regular decline of near-wall streaks and vortex structures with respect to the flow direction, leading to the effective suppression of turbulence generation and significant reduction in skin-friction drag. In addition, experiments are carried out in a water tunnel via electro-magnetic (EM) actuators designed to produce the bidirectional traveling wave excitation as described in calculations. As a result, the actual substantial drag reduction is realized successfully in these experiments. (22 refs.)Main Heading: Oscillating flowControlled terms: Channel flow - Direct numerical simulation - Drag - Drag reduction - Lorentz force - Magnetic actuators - Numerical models - Skin friction - Tunnels - Turbulence - Vortex flowUncontrolled terms: Control parameters - Effective suppression - Skin-friction drag - Traveling wave excitation - Turbulence controls - Turbulence generation - Turbulent channel flows - Turbulent controlsClassification Code: 401.2 Tunnels and Tunneling - 631.1 Fluid Flow, General - 701 Electricity and Magnetism - 704 Electric Components and Equipment - 921 Mathematics

Database: Compendex

Facile synthesis of wheat bran-derived honeycomb-like hierarchical carbon for advanced symmetric supercapacitor applications

Wang, Dewei1; Min, Yonggang1; Yu, Youhai1 Source: Journal of Solid State Electrochemistry, v 19, n 2, p 577-584, 2014

; ISSN: 14328488; DOI: 10.1007/s10008-014-2639-0;

Publisher: Springer New York LLCAuthor affiliation: 1 Institute of Advanced Materials, State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: A novel honeycomb-like hierarchical carbon (HHC) derived from wheat bran has been obtained by the facile and environmentally friendly method via hydrothermal carbonization of wheat bran followed by KOH activation process at mild conditions without any template. The prepared carbon has a large Brunauer–Emmett–Teller (BET) surface area of 2,189.2 m2 g−1 and pore volumes of up to 1.1 cm3 g−1. The performance of the HHC as electrodes for electrochemical supercapacitors was evaluated in a symmetric two-electrode cell configuration with 6 M KOH and 1 M TEABF<inf>4</inf>/AN as the electrolytes. Electrochemical studies show that the supercapacitors based on the as-prepared HHC exhibit an excellent capacitive performance in both aqueous and organic electrolytes. We attribute the outstanding capacitive behavior of HHC to their unique structure and high accessible surface area. Considering that the cost-effective and feasible process, this facile technique presented here will not only provide a promising method for the production of biomass-derived hierarchical carbon but also put forward the application of carbon materials in energy storage and conversion. © 2014, Springer-Verlag Berlin Heidelberg. (30 refs.)Main Heading: Electrolytic capacitorsControlled terms: Biomass - Carbon - Carbonization - Cost effectiveness - Electrochemical electrodes - Electrolytes - Honeycomb structures - ThermochemistryUncontrolled terms: Accessible surface areas - Adjacent vertices - Capacitive performance - Chromatic index - Degenerate graphs - Edge coloring - Electrochemical studies - Electrochemical supercapacitor - Energy storage and conversions - Hydrothermal carbonization - Maximum degree - Super capacitor - Supercapacitor application

Database: Compendex

Plasmonic characteristics in nanoscale graphene resonator-coupled waveguides

Lu, Hua1, 2 Source: Applied Physics B: Lasers and Optics, v 118, n 1, November 4, 2014

; ISSN: 09462171; DOI: 10.1007/s00340-014-5954-3;

Publisher: Springer VerlagAuthor affiliation: 1 Centre for Micro-Photonics and CUDOS, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn; VIC, Australia2 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: In this paper, we numerically and theoretically investigate the propagation of surface plasmon polaritons in a graphene-based resonator-coupled waveguide system, consisting of a monolayer graphene ribbon coupling to two graphene sheets. The resonance wavelength of this system can be easily tuned by adjusting the chemical potential and the width of the graphene ribbon. Both resonance bandwidth and spectral transmission characteristics of the structure strongly depend on the coupling distance and overlap length between the graphene ribbon and graphene sheets. The structural symmetry is found to be another essential parameter. The presented results may pave the way toward the dynamic control of light propagation in graphene-based structures and the realization of tunable graphene-based optoelectronic devices. © 2014 Springer-Verlag Berlin HeidelbergMain Heading: GrapheneControlled terms: Electromagnetic wave polarization - Light propagation - Optoelectronic devices - Plasmons - Resonators - WaveguidesUncontrolled terms: Coupled waveguide systems - Coupled waveguides - Dynamic controls - Graphene ribbons - Resonance wavelengths - Spectral transmission - Structural symmetry - Surface plasmon polaritonsClassification Code: 711 Electromagnetic Waves - 712.1 Semiconducting Materials - 714 Electronic Components and Tubes - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Novel space communication technology based on modulated x-ray source

Sheng, Li-Zhi1; Zhao, Bao-Sheng1; Liu, Yong-An1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9207, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628412345; DOI: 10.1117/12.2062712; Article number: 920716; Conference: Advances in X-Ray/EUV Optics and Components IX, August 18, 2014 - August 20, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: A novel space communication method is presented in this paper based on X-ray photons. As a result of its short wavelength and great penetrability, X-ray has no attenuation for transmission in space when its photon energy is more than 10keV (λ<0.1nm). Thus a communication technology of long distance signal transmission in space can be achieved with smaller volume, lower weight and lower power. Therefore, X-ray communication (XCOM) is especially valuable to the deep space missions, which will be able to realize higher data rates, smaller SWAP than with RF and laser communications. Using X-ray photons as information carrier will not only be a good complement to laser and RF communications, but will also have unique applications when RF and laser signals are not available like the spacecraft's re-entering to the earth. High-speed modulation and high-sensitivity detection of X-rays are two major technical issues which should be addressed in order for the X-ray communication to take place. A Grid-controlled Modulated X-ray tube (GMXT) is proposed and developed as X-ray transmitter. One or more specially designed grid electrodes are added to the traditional X-ray tube to modulate the electrons. The communication signal is coded and applied to the modulated grid electrode, and then the corresponding X-ray signals are generated and sent out. X-ray detector based on micro-channel plate(MCP) is used as communication receiver because of its high temporal resolution. An audio communication experiment system based on XCOM is setup in laboratory including the X-ray transmitter and the receiver. X-ray communication is successfully demonstrated and the communication speed reaches 64 kilobits per second in a vacuum tube of 6 meters long. As a new concept of space communication, X-ray communication will have more important scientific significance and application prospects when technologies for X-ray modulation and detection are further developed. © 2014 SPIE. (5 refs.)Main Heading: X ray tubesControlled terms: Electrodes - Electron tubes - Image storage tubes - Interplanetary flight - Light - Modulation - Photons - Signal detection - Space flight - Space research - Transmitters - Tubes (components) - X ray apparatus - X raysUncontrolled terms: Communication receivers - Communication signals - Communication technologies - Deep-space exploration - High temporal resolution - High-sensitivity detection - High-speed modulation - Space communicationsClassification Code: 422.1 Strength of Building Materials : Test Equipment - 616.1 Heat Exchange Equipment and Components - 656.1 Space Flight - 656.2 Space Research - 714.1 Electron Tubes - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 741.1 Light/Optics - 801 Chemistry - 932.1 High Energy Physics

Database: Compendex

Monte Carlo simulation of HERD calorimeter

Xu, M.1; Chen, G.M.1; Dong, Y.W.2; Lu, J.G.2; Quan, Z.3; Wang, L.2; Wang, Z.G.1; Wu, B.B.1; Zhang, S.N.1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9144, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9780819496126; DOI: 10.1117/12.2055319; Article number: 91443S; Conference: Space Telescopes and Instrumentation 2014: Ultraviolet to Gamma Ray, June 22, 2014 - June 26, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Abstract: The High Energy cosmic-Radiation Detection (HERD) facility onboard China's Space Station is planned for operation starting around 2020 for about 10 years. It is designed as a next generation space facility focused on indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. The calorimeter plays an essential role in the main scientific objectives of HERD. A 3-D cubic calorimeter filled with high granularity crystals as active material is a very promising choice for the calorimeter. HERD is mainly composed of a 3-D calorimeter (CALO) surrounded by silicon trackers (TK) from all five sides except the bottom. CALO is made of 9261 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. Here the simulation results of the performance of CALO with GEANT4 and FLUKA are presented: 1) the total absorption CALO and its absorption depth for precise energy measurements (energy resolution: 1% for electrons and gammarays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV); 2) its granularity for particle identification (electron/proton separation power better than 10-5); 3) the homogenous geometry for detecting particles arriving from every unblocked direction for large effective geometrical factor (<3 m2sr for electron and diffuse gammarays, >2 m2sr for cosmic ray nuclei); 4) expected observational results such as gamma-ray line spectrum from dark matter annihilation and spectrum measurement of various cosmic ray chemical components. © 2014 SPIE. (30 refs.)Main Heading: Gamma raysControlled terms: Absorption spectroscopy - Calorimeters - Cosmic ray measurement - Cosmic rays - Cosmology - Galaxies - Intelligent systems - Monte Carlo methods - Particles (particulate matter) - Space stations - Space telescopesUncontrolled terms: Composition measurements - Dark matter - Dark matter searches - MC simulation - Particle identifications - Precise energy measurement - Scientific objectives - Space experimentsClassification Code: 656.1 Space Flight - 657 Space Physics - 657.2 Extraterrestrial Physics and Stellar Phenomena - 723.4 Artificial Intelligence - 741 Light, Optics and Optical Devices - 801 Chemistry - 804 Chemical Products Generally - 922.2 Mathematical Statistics - 932 High Energy Physics; Nuclear Physics; Plasma Physics - 932.1 High Energy Physics - 951 Materials Science

Database: Compendex

Theory of circular plate for mirrors on back-point support

Liang, Yuanqing1, 2; Zhou, Sizhong1; Jiang, Bo1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2067980; Article number: 928011; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In space reflective optical system, the back-point support is one of the widely used support means. For back-point support method, the support points position are important for the deformation of the reflective surface, find the best support points position of the mirror is particularly important. A new technique of mass allocation was discovered by using the theory of circular plate in this paper, and then the mass allocation method was used to look for the locations of the back support points on a single ring for a circular mirror having a central hole (primary mirror of Cassegrain telescope). Then the Ansys software was used to calculate the deformation of the reflective surface when the mirror supported under different radius. It was validated that the mirror surface deformation is minimized due to gravity when supported in these positions which confirmed by mass allocation. It was proved that mass allocation is a simple and effective way to find the optimum support location of back-point support. © 2014 SPIE. (6 refs.)Main Heading: Optical testingControlled terms: Deformation - Gravitation - Manufacture - Mirrors - Optical systems - TelescopesUncontrolled terms: Cassegrain telescopes - Circular mirrors - Circular plates - Mass allocation - Optimum location - Point support - Reflective optical system - Reflective surfacesClassification Code: 421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 537.1 Heat Treatment Processes - 741.3 Optical Devices and Systems - 931.5 Gravitation, Relativity and String Theory

Database: Compendex

Parallel programming design of star image registration based on GPU

Chen, Xi1, 2; Qiu, Yuehong1; Yi, Hongwei1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 11, p 3756-3761, November 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: The speed of star image registration affects the whole speed of the processing of the star image as star image registration is one of the most important steps of star image processing. In recent years, the general purpose computing of graphic process unit(GPU)has a rapid development. In this paper, the computing power of GPU for the general purpose computing and the problem of the speeding up of processing of star image registration were combined to study the accelerated processing algorithm based on GPU. A parallel model of GPU for the registration algorithm was proposed and CUDA programming language was uesd to realize it. Experiment result shows that the parallel model also fulfills the purpose of the image registration and has a 29.043X speedup compared with the serial CPU program. (8 refs.)Main Heading: Image registrationControlled terms: Acceleration - Algorithms - Image processing - Parallel programming - StarsUncontrolled terms: Computing power - CUDA - General-purpose computing - GPU - Graphic process units - Processing algorithms - Registration algorithms - Star imagesClassification Code: 657.2 Extraterrestrial Physics and Stellar Phenomena - 723 Computer Software, Data Handling and Applications - 921 Mathematics - 931.1 Mechanics

Database: Compendex

Effects of Sb<inf>2</inf>O<inf>3</inf> on the mechanical properties of the borosilicate foam glasses sintered at low temperature

Zhai, Chenxi1; Li, Zhe2; Zhu, Yumei1; Zhang, Jing1; Wang, Xiuduo3; Zhao, Lejun3; Pan, Liuming3; Wang, Pengfei4 Source: Advances in Materials Science and Engineering, v 2014, December 28, 2014

; ISSN: 16878434, E-ISSN: 16878442; DOI: 10.1155/2014/703194; Article number: 703194;

Publisher: Hindawi Publishing CorporationAuthor affiliation: 1 Key Laboratory for Advanced Ceramics and Machining Technology, Ministry of Education, Tianjin University, Tianjin, China2 School of Electronic Information Engineering, Tianjin University, Tianjin, China3 Tianjin Municipal Engineering Design and Research Institute, Tianjin, China4 State Key Laboratory of Transient Optics and Photonics, Institute of Advanced Materials, Chinese Academy of Sciences, Xi'an, China

Abstract: The physical properties and microstructure of a new kind of borosilicate foam glasses with different Sb<inf>2</inf>O<inf>3</inf> doping content are comprehensively investigated. The experimental results show that appropriate addition of Sb<inf>2</inf>O<inf>3</inf> has positive impact on the bulk porosity and compressive strength of the foam glass. It is more suitable in this work to introduce 0.9 wt.% Sb<inf>2</inf>O<inf>3</inf> into the Na<inf>2</inf>O-K<inf>2</inf>O-B<inf>2</inf>O<inf>3</inf>-Al<inf>2</inf>O<inf>3</inf>-SiO<inf>2</inf> basic foam glass component and sinter at 775°C. And the obtained foam glasses present much more uniform microstructure, large pore size, and smooth cell walls, which bring them with better performance including a lower bulk density, low water absorption, and an appreciable compressive strength. The microstructure analysis indicates that, with the increase of the content of Sb<inf>2</inf>O<inf>3</inf> additives, the cell size tends to increase at first and then decreases. Larger amounts of Sb<inf>2</inf>O<inf>3</inf> do not change the crystalline phase of foam glass but increase its vitrification. It is meaningful to prepare the foam glass at a relatively low temperature for reducing the heat energy consumption. (24 refs.)Main Heading: GlassControlled terms: Biomechanics - Compressive strength - Energy utilization - Mechanical properties - Microstructure - Pore size - Sintering - Temperature - Water absorptionUncontrolled terms: Better performance - Crystalline phase - Heat energy consumption - Large pore size - Low temperatures - Microstructure analysis - Properties and microstructures - Uniform microstructureClassification Code: 421 Strength of Building Materials; Mechanical Properties - 525.3 Energy Utilization - 641.1 Thermodynamics - 802.3 Chemical Operations - 812.3 Glass - 931.1 Mechanics - 933 Solid State Physics - 951 Materials Science

Database: Compendex

Direct generation of orthogonally polarized photon pairs on a chip via spontaneous non-degenerate FWM

Reimer, Christian1; Caspani, Lucia1; Jestin, Yoann1; Clerici, Matteo1, 2; Ferrera, Marcello1, 2; Razzari, Luca1; Peccianti, Marco1, 3; Pasquazi, Alessia1, 3; Litte, Brent E.4; Chu, Sai T.5; Moss, David J.1, 6; Morandotti, Roberto1 Source: Nonlinear Photonics, NP 2014, July 21, 2014; ISBN-13: 9781557528209;

Publisher: Optical Society of America (OSA)Author affiliation: 1 INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes; QC, Canada2 School of Engineering and Physical Sciences, Heriot-Watt University, SUPA, Edinburgh, United Kingdom3 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, United Kingdom4 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, China5 Department of Physics and Material Science, City University of Hong Kong, Tat Chee Avenue, Hong Kong, China6 School of Electrical and Computer Engineering, RMIT University, Melbourne; VIC, Australia

Abstract: By suppressing stimulated processes, we demonstrate the direct generation of orthogonally polarized photon pairs via spontaneous non-degenerate four-wave-mixing (FWM) between orthogonally polarized pumps in a CMOS-compatible micro-ring. Photon coincidences and optical parametric oscillation are measured. © 2014 OSA. (10 refs.)Main Heading: Four wave mixingControlled terms: PhotonsUncontrolled terms: CMOS Compatible - Degenerate four-wave mixing - Direct generation - Microrings - Optical parametric oscillations - Polarized photons - Stimulated processClassification Code: 711.1 Electromagnetic Waves in Different Media - 741.1 Light/Optics

Database: Compendex

An improvement of embedded zerotree wavelet coding based on compressed sensing

Chen, Zhi1; Mu, Chenhao1; Xu, Fan2 Source: Proceedings of the IEEE International Conference on Software Engineering and Service Sciences, ICSESS, p 1177-1180, October 21, 2014

; ISSN: 23270586, E-ISSN: 23270594; ISBN-13: 9781479932788; DOI: 10.1109/ICSESS.2014.6933776; Article number: 6933776; Conference: 2014 5th IEEE International Conference on Software Engineering and Service Science, ICSESS 2014, June 27, 2014 - June 29, 2014;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Embedded zero-tree wavelet (EZW) is a kind of image compression algorithm which provides high compression rates fast. In order to improve the quality of reconstructed image after decoding, in this research, we put forward an improvement of embedded zerotree wavelet coding and simulate this new algorithm. This method takes full advantages of the Compressed Sensing (CS) theory and EZW. Simulation results demonstrated that the proposed method improved the quality of the unzipped image significantly. © 2014 IEEE. (11 refs.)Main Heading: Image codingControlled terms: Algorithms - Codes (symbols) - Compressed sensing - Forestry - Image compression - Signal reconstruction - Software engineering - Trees (mathematics)Uncontrolled terms: Compressive sensing - Embedded coding - Embedded zero tree wavelet - Embedded zero-tree wavelet coding - Image compression algorithms - Quality of reconstructed images - Wavelet - ZerotreesClassification Code: 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 821.0 Woodlands and Forestry - 921 Mathematics - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Mid-infrared emissions of Pr3+-doped GeS<inf>2</inf>-Ga<inf>2</inf>S<inf>3</inf>-CdI<inf>2</inf>chalcohalide glasses

Lu, Chunfeng1; Guo, Haitao1; Xu, Yantao1; Hou, Chaoqi1; Lu, Min1; He, Xin2; Wang, Pengfei1; Li, Weinan1; Peng, Bo2 Source: Materials Research Bulletin, v 60, p 391-396, December 2014

; ISSN: 00255408; DOI: 10.1016/j.materresbull.2014.09.003;

Publisher: Elsevier LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, Shaanxi, China2 School of Applied Physics and Materials, Wuyi University, Jiangmen, Guangdong, China

Abstract: For elucidation of the glass composition's influence on the spectroscopic properties in the chalcohalide system and the discovery of a new material for applications in mid-infrared fiber-lasers, a serial Pr3+-doped (100 - x)(0.8GeS<inf>2</inf>·0.2Ga<inf>2</inf>S<inf>3</inf>)xCdI<inf>2</inf>(x = 5, 10, 15 and 20) chalcohalide glasses were prepared. &sim;4.6 μm mid-infrared fluorescence emission from Pr3+in the sulfide glass is successfully observed at room temperature excited by a 2.01 μm Tm3+:YAG ceramic laser system, and the effective line-width of fluorescence band is 106-227 nm. Intense compositional dependence of mid-infrared emissions is found. The radiative rates of Pr3+ions in these glasses were calculated by using the Judd-Ofelt theory. © 2014 Elsevier Ltd. All rights reserved. (19 refs.)Main Heading: GlassControlled terms: Fiber lasers - Fluorescence - Infrared devices - Inorganic compounds - Judd-Ofelt theory - Optical propertiesUncontrolled terms: Chalcohalide glass - Compositional dependence - Fluorescence band - Glass compositions - Mid-infrared emission - Radiative rates - Room temperature - Spectroscopic propertyClassification Code: 741 Light, Optics and Optical Devices - 804.2 Inorganic Compounds - 812.3 Glass - 931.3 Atomic and Molecular Physics

Database: Compendex

Efficient optimization of super-oscillatory lens and transfer function analysis in confocal scanning microscopy

Liu, Tao1, 2; Liu, Jian1; Zhang, He1; Tan, Jiubin2 Source: Optics Communications, v 319, p 31-35, May 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2013.12.054;

Publisher: ElsevierAuthor affiliation: 1 Center of Ultra-precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin, China2 Institute of Precision Engineering, Xi'An Jiaotong University, Xi'an, China

Abstract: Super-oscillatory lens (SOL) provides a promising way to achieve subwavelength focusing in the regime of far-field optics and realize super-resolution imaging in confocal scanning microscopy (CSM). Both binary amplitude and phase SOLs are designed with an efficient optimization method using genetic algorithm and fast Hankel transform algorithm either in oil immersion medium or in air. A much brighter hotspot is readily focused by a phase SOL compared with the amplitude counterpart, e.g., 5.8 times as bright as the latter. To fundamentally interpret the super-resolution imaging mechanism by SOL in CSM, transfer function analysis is conducted compared with basic confocal imaging. The coherent transfer function (CTF) is derived and numerically calculated. The extension of the cutoff frequency and the remarkable enhancement of the magnitude of CTF in the high frequency passband account for super-resolution imaging by SOL in CSM; however, the limited extension of the frequency domain also implies that the attainable resolution is physically limited. (23 refs.)Main Heading: Transfer functionsControlled terms: Confocal microscopy - Cutoff frequency - Genetic algorithms - Image reconstruction - Optical resolving power - SolsUncontrolled terms: Binary optics - Coherent transfer functions - Confocal scanning microscopy - Optimization method - Sub-wavelength focusing - Super resolution - Super resolution imaging - Transfer function analysisClassification Code: 703.1 Electric Networks - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 804 Chemical Products Generally - 921 Mathematics

Database: Compendex

Femtoseoncd laser-induced ablation regimes and thresholds in a nickel-based superalloy

Zhang, Wei1; Feng, Qiang2; Cheng, Guanghua3; Zhang, Xiaobing1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 12, December 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.1232001; Article number: 1232001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Science and Technology on Power Beam Processes Laboratory, Beijing Aeronautical Manufacturing Technology Research Institute, Beijing , China2 National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing , China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: Femtosecond laser-induced ablation regimes and ablation thresholds of single-crystal nickel-based superalloy are investigated by means of microstructure on machined surface and trench as a function of laser fluence of 0~12.8 J/cm2 and the number of pulses of 0~8000. Two distinct ablation regimes (no-melting and melting ablation regime) are observed, dependent on the incident laser fluence. The ablation threshold fluences for these two ablation regimes are determined to be 0.23 J/cm2 and 1.21 J/cm2 in the superalloy. And the incubation factors for these two ablation regimes are determined to be 0.90 and 0.92. Furthermore, the relationship between both ablation regimes and ablation thresholds and their parametric dependence is established. The experimental results have practical guiding for processing nickel-based aviation of no recast layer and micro-cracks. (22 refs.)Main Heading: AblationControlled terms: Crystal microstructure - Laser ablation - Melting - Nickel - Single crystals - Superalloys - Ultrashort pulsesUncontrolled terms: Ablation regime - Ablation thresholds - Laser-induced ablation - Machined surface - Nickel- based superalloys - Parametric dependence - Single crystal nickel based superalloy - Ultrafast opticsClassification Code: 531 Metallurgy and Metallography - 531.1 Metallurgy - 548.1 Nickel - 641.2 Heat Transfer - 744.1 Lasers, General - 933.1 Crystalline Solids - 933.1.1 Crystal Lattice

Database: Compendex

Research of joint transform correlator stablization image system based on field programmable gate array

Yang, Wencai1; Fan, Xuewu1; Wang, Fengtao1; Yi, Hongwei1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, December 1, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.s212006; Article number: s212006;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Scienses, Xi'an; Shaanxi, China

Abstract: Sensor images are easily blurred by the offset of camera focal plane and the observing targets during push-broom space camera exposure time. In order to obtain higher quality images, this camera system needs image stabilization operation. However, the key is restraining imaging platform vibration and getting precisely trajectory of platform in real-time. The acquisition of platform motion vector in high-speed and accurately in the imaging process has become the focus of the development direction of high resolution imaging. Methods often used to obtain targets motion vector are too slow to get targets trajectory accurately in-real time. A joint transform correlator based on field programmable gate array (FPGA) instead of the one based on Fourier optical transform is designed and the calculation precision is up to 0.1 pixel. (7 refs.)Main Heading: Field programmable gate arrays (FPGA)Controlled terms: Cameras - Detectors - Fast Fourier transforms - Image compression - Image reconstruction - Logic gates - MOS devices - Signal receivers - StabilizationUncontrolled terms: Calculation precision - Development directions - High-resolution imaging - Image stabilization - Joint transform correlators - Metal oxide semiconductor - Optical transform - Platform vibrationsClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 721.3 Computer Circuits - 741 Light, Optics and Optical Devices - 742.2 Photographic Equipment - 914 Safety Engineering - 921.3 Mathematical Transformations - 951 Materials Science

Database: Compendex

Giant and tunable electric field enhancement in the terahertz regime

Lu, Xiaoyuan1; Wan, Rengang1; Wang, Guoxi1; Zhang, Tongyi1; Zhang, Wenfu1 Source: Optics Express, v 22, n 22, p 27001-27006, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.027001;

Abstract: A novel array of slits design combining the nano-slit grating and dielectric-metal is proposed to obtain giant and tunable electric field enhancement in the terahertz regime. The maximum amplitude of electric field is more than 6000 times larger than that of the incident electric field. It is found that the enhancement depends primarily on the stripe and nano-slits width of grating, as well as the thickness of spacer layer. This property is particularly beneficial for the realization of ultra-sensitive nanoparticles detection and nonlinear optics in the terahertz range, such as the second harmonic generation (SHG). (25 refs.)Main Heading: Harmonic generationControlled terms: Electric field effects - Nonlinear opticsUncontrolled terms: Electric field enhancement - Maximum amplitude - Nanoslits - Spacer layer - Tera Hertz - Terahertz range - Ultra sensitivesClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 741.1.1 Nonlinear Optics - 751.1 Acoustic Waves

Database: Compendex

CMOS compatible integrated all-optical radio frequency spectrum analyzer

Ferrera, Marcello1, 2; Reimer, Christian1; Pasquazi, Alessia3; Peccianti, Marco3; Clerici, Matteo1, 2; Caspani, Lucia1; Chu, Sai T.4; Little, Brent E.5; Morandotti, Roberto1; Moss, David J.1, 6 Source: Optics Express, v 22, n 18, p 21488-21498, September 8, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.021488;

Publisher: Optical Society of American (OSA)Author affiliation: 1 INRS-EMT, 1650 Boulevard Lionel Boulet, Varennes; QC, Canada2 School of Engineering and Physical Sciences, Heriot-Watt University, David Brewster Building, Edinburgh, United Kingdom3 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, United Kingdom4 Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Hong Kong, Hong Kong5 Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China6 School of Electrical and Computer Engineering, RMIT University, Melbourne; VIC, Australia

Abstract: We report an integrated all-optical radio frequency spectrum analyzer based on a &sim;4cm long doped silica glass waveguide, with a bandwidth greater than 2.5 THz. We use this device to characterize the intensity power spectrum of ultrahigh repetition rate mode-locked lasers at repetition rates up to 400 GHz, and observe dynamic noise related behavior not observable with other techniques. ©2014 Optical Society of America. (29 refs.)Main Heading: Spectrum analyzersControlled terms: Mode-locked fiber lasers - Radio waves - SpectroscopyUncontrolled terms: CMOS Compatible - Doped silicas - Dynamic noise - Glass waveguides - Mode-locked laser - Radio frequency spectrum - Repetition rate - Ultrahigh repetition ratesClassification Code: 711 Electromagnetic Waves - 744.1 Lasers, General - 801 Chemistry - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Mathematical model for the measurement of high dynamic range laser focal spot

Wang, Zheng-Zhou1, 2; Wang, Wei1, 2; Xia, Yan-Wen3 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 10, October 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144310.1010002; Article number: 1010002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang; Sichuan, China

Abstract: A measurement method of the high dynamic range laser focal spot was proposed. First of all, the mathematical model of schlieren method to measure the far-field focal spot was constructed, the main lobe intensity amplification coefficient and the laser spot amplification coefficient were confirmed, and the parameters were calibrated by automatic alignment laser beam; Secondly, the schlieren ball was put in focus position of side lobe laser beam to shade the spot centre and side lobe image was captured accurately by integrated diagnostic beam fast automatic alignment system; Finally, the schlieren reconstructed algorithm was optimized by calculating side lobe image centre and image fusion, and the error of traditional schlieren reconstruction method for side lobe center was decreased and the obvious edge of reconstructed image was eliminated. The application in parameter measurement integrated diagnostic system of the high power laser facility to measure far-field laser focal spot shows that the method can measure the far field distribution of high dynamic range laser focal spot exactly if the parameter of the mathematical model is calibrated accurately and the schlieren reconstructed algorithm is optimized. (11 refs.)Main Heading: Mathematical modelsControlled terms: Alignment - Calibration - Edge detection - High power lasers - Image fusion - Laser beams - Parameter estimationUncontrolled terms: Automatic alignment - Far-field focal spots - High dynamic range - Main lobes - Schlieren method - Side lobesClassification Code: 601.1 Mechanical Devices - 716 Telecommunication; Radar, Radio and Television - 723.2 Data Processing and Image Processing - 731.1 Control Systems - 744.1 Lasers, General - 744.8 Laser Beam Interactions - 921 Mathematics - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

An Ytterbium-doped fiber laser with dark and Q-switched pulse generation using graphene-oxide as saturable absorber

Zhao, Junqing1; Wang, Yonggang2; Yan, Peiguang1; Ruan, Shuangchen1; Tsang, Yuen3; Zhang, Gelin1; Li, Huiquan1 Source: Optics Communications, v 312, p 227-232, February 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2013.09.038;

Publisher: ElsevierAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, Shenzhen University, Shenzhen, Guangdong, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China3 Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, Hong Kong

Abstract: We demonstrate an ytterbium-doped fiber (YDF) laser being able to generate dark pulses and Q-switched pulses by using a graphene oxide (GO) based composite as saturable absorber (SA). These operation regimes are realized for the first time in a 1-μm band fiber laser as far as our best knowledge. In the fabrication of GO based saturable absorber (GOSA), a vertical evaporation process is included, which results in a GO concentration and thickness variable SA. The generated dark pulse has pulse duration in ns-scale. In the Q-switched operation, pulses with durations from 5.321 μs to 2.655 μs and repetition rates from 28.47 kHz to 58.95 kHz can be obtained as the launched pump power is changed. The transition from the dark pulse to Q-switched operations can be clearly seen as the pump power is increased to a certain value. The radio frequency (RF) and optical spectrum variations with respect to the change of pump power have also been analyzed in detail. (22 refs.)Main Heading: Pulse generatorsControlled terms: Fiber lasers - Fibers - Graphene - Optical pumping - Pulse repetition rate - Q switching - Saturable absorbers - YtterbiumUncontrolled terms: Dark pulse - Evaporation process - Graphene oxides - Launched pump power - Q-switched - Q-switched operation - Ytterbium doped fibers - Ytterbium-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 713.4 Pulse Circuits - 741.1 Light/Optics - 741.1.2 Fiber Optics - 744 Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

Reaserch on loss of fiber optic rotary joint based on virtual prototype

Zhang, Min-Rui1, 2; He, Zheng-Quan1; Hu, Bao-Wen1; Kong, De-Peng1; Du, Xin-Chao1, 2; Tian, Jin-Shou1; Li, Yu-Lin1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 12, December 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144312.1222001; Article number: 1222001;

Abstract: A fiber optic rotary joint loss analysis method based on virtual prototype was proposed. The input-output equations of light in dove prism are derived. A hybrid architecture based on ray tracing model and analytical model was employed in a homogeneous coordinate system; the angle and position deviations of collimating lens and dove prism were considered as input error in the model as well as bearing clearance and gear precision. 30000 random samples, of which angle precision is ±100″ and position precision is ±0.01 mm, were studied. The result shows that angle error of dove prism and collimating lens must be ±1' or less while the maximum loss is required less than 4dB, the distribution of loss P(X&rang;3 dB) is required less than 0.5%. (14 refs.)Main Heading: Optical fiber communicationControlled terms: Analytical models - Fiber optic networks - Fiber optics - Fibers - Optical communication - Optical losses - Prisms - Ray tracing - Virtual prototypingUncontrolled terms: Bearing clearance - Fiber optic rotary joints - Geometric optics - Homogeneous coordinates - Hybrid architectures - Loss analysis - Position precision - Ray-tracing modelClassification Code: 717.1 Optical Communication Systems - 741 Light, Optics and Optical Devices - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications - 921 Mathematics

Database: Compendex

Corner detection using gabor filters

Zhang, Wei-Chuan1; Wang, Fu-Ping2; Zhu, Lei1; Zhou, Zuo-Feng3 Source: IET Image Processing, v 8, n 11, p 639-646, November 14, 2014

; ISSN: 17519659; DOI: 10.1049/iet-ipr.2013.0641;

Publisher: Institution of Engineering and TechnologyAuthor affiliation: 1 College of Electronics and Information, Xi'an Polytechnic University, Xi'an, China2 Xidian University, Xi'an, China3 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: This study proposes a contour-based corner detector using the magnitude responses of the imaginary part of the Gabor filters on contours. Unlike the traditional contour-based methods that detect corners by analysing the shape of the edge contours and searching for local curvature maxima points on planar curves, the proposed corner detector combines the pixels of the edge contours and their corresponding grey-variation information. Firstly, edge contours are extracted from the original image using Canny edge detector. Secondly, the imaginary parts of the Gabor filters are used to smooth the pixels on the edge contours. At each edge pixel, the magnitude responses at each direction are normalised by their values and the sum of the normalised magnitude response at each direction is used to extract corners from edge contours. Thirdly, both the magnitude response threshold and the angle threshold are used to remove the weak or false corners. Finally, the proposed detector is compared with five state-of-the-art detectors on some grey-level images. The results from the experiment reveal that the proposed detector is more competitive with respect to detection accuracy, localisation accuracy, affine transforms and noise-robustness. (26 refs.)Main Heading: Edge detectionControlled terms: Affine transforms - Gabor filters - PixelsUncontrolled terms: Canny edge detectors - Contour-based methods - Corner detection - Detection accuracy - Grey-level images - Magnitude response - Noise robustness - Original imagesClassification Code: 703.2 Electric Filters - 716 Telecommunication; Radar, Radio and Television - 723.5 Computer Applications - 921.3 Mathematical Transformations

Database: Compendex

Adaptive nonuniformity correction for IRFPA based on Bayesian estimation

Leng, Hanbing1; Xie, Qingsheng1; Liu, Wei1; Yi, Bo1; Tang, Linao1; Zhang, Jian1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 9, September 10, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0910001; Article number: 0910001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: After long time working, the response characteristics of infrared focal plane array (IRFPA) often drift slowly, and the image quality always degrades. Aiming at the problem, the characteristic of residual noise after two point correction (TPC) is analyzed. An adaptive non-uniformity correction algorithm is proposed based on the TPC algorithm. The images after TPC is decomposed by wavelet, and the Bayesian threshold is used to estimate signal and noise variance point by point, the residual nonuniformity noise is calculated and removed. Experimental results show that the proposed algorithm can remove the residual nonuniformity noise effectively and avoids the image degradation caused by the response drift of IRFPA. (12 refs.)Main Heading: FocusingControlled terms: Bayesian networks - Infrared detectorsUncontrolled terms: Bayesian - Infrared focal plane arrays - Maging system - Non-uniformities - Nonuniformity correctionClassification Code: 711.1 Electromagnetic Waves in Different Media - 741.3 Optical Devices and Systems - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Design of 2-D reflection mirror gimbal for lunar based astronomy optical telescope

Huang, Jing1; Liu, Zhao-Hui1; Xie, You-Jin1; Li, Zhi-Guo1; Wang, Zhen-Yu1 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 8, p 2173-2179, August 1, 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142208.2173;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: To implement the astronomical observation on the moon, the thermal analysis and structure design of a 2D reflection mirror gimbal for the lunar based astronomy optical telescope were performed. The 2D rotary structure of reflection mirror was designed based on lightweighting method to reduce the load mass. Because an external rotor mechanism was used for the vertical shaft, the first order mode of the system along the emission direction was greatly improved. For a larger span in the horizontal shaft, a shaft system with one fixed end and another free end was adopted. Moreover, the clearance of deep groove ball bearings was designed rationally to eliminate the block of the rotary structure caused by temperature changes on the moon. In order to meet the high accuracy, the reflection mirror gimbal used a worm gear and a step motor to drive the gimbal and to control the machining in a strict technology. In addition, an optics switch was used to achieve high accuracy position and make the accuracy of gimbal be better than 60″. Experiments show that the first order resonant frequency of the system can reach 81 Hz along the rocket-firing track, the mechanism works well at -25 to + 60 without stuck phenomenon and its direction accuracy is less than 60″. These results demonstrate that the system is characterized by high accuracy, high reliability and light weight. (11 refs.)Main Heading: MirrorsControlled terms: Astronomy - Deep groove ball bearings - Design - Moon - Natural frequencies - Optical telescopes - Rockets - Stepping motors - ThermoanalysisUncontrolled terms: Astronomical observation - High reliability - Horizontal shafts - Lightweighting - Position accuracy - Reflection mirrors - Structure design - Temperature changesClassification Code: 404.1 Military Engineering - 408 Structural Design - 601.2 Machine Components - 657.2 Extraterrestrial Physics and Stellar Phenomena - 705.3 Electric Motors - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 801 Chemistry

Database: Compendex

Upgrading optical information of rotating mirror cameras

Li, Jingzhen1; Sun, Fengshan2; Huang, Hongbin1; Gong, Xiangdong1; Chen, Hongyi1; Lu, Xiaowei1; Cai, Yi1 Source: Review of Scientific Instruments, v 85, n 11, November 1, 2014

; ISSN: 00346748, E-ISSN: 10897623; DOI: 10.1063/1.4900404; Article number: 113701;

Publisher: American Institute of Physics Inc.Author affiliation: 1 Institute of Photonic Engineering, College of Electronic Science and Technology, Shenzhen University, Shenzhen, China2 Xian Institute of Optics and Precision Mechanics, Academia Sinica, Xian, China

Abstract: To date, rotating mirror (RM) cameras still serve as indispensable imaging equipment for the diagnosis of microsecond transient processes due to their excellent characteristics. This paper, for upgrading the optical information capacity of the cameras, presents the new optical acceleration principle to increase the framing frequency or scanning velocity, the new design theory without principle errors instead of the classical theories with some flaws in principle to have applied to design our simultaneous streak and framing rotating mirror camera with continuous access, and the new rotating mirror with novel structure, made of an aluminum alloy, to have considerably reduced lateral deformation of the RM and improved the performance of the camera. © 2014 AIP Publishing LLC. (23 refs.)Main Heading: MirrorsControlled terms: CamerasUncontrolled terms: Classical theory - Imaging equipment - Lateral deformation - Optical acceleration - Optical information - Rotating mirrors - Scanning velocity - Transient processClassification Code: 741.3 Optical Devices and Systems - 742.2 Photographic Equipment

Database: Compendex

Lazy random walks for superpixel segmentation

Shen, Jianbing1; Du, Yunfan1; Wang, Wenguan1; Li, Xuelong2 Source: IEEE Transactions on Image Processing, v 23, n 4, p 1451-1462, April 2014

; ISSN: 10577149; DOI: 10.1109/TIP.2014.2302892; Article number: 6725608;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Beijing Laboratory of Intelligent Information Technology, School of Computer Science, Beijing Institute of Technology, Beijing 100081, China2 Center for OPTical IMagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: We present a novel image superpixel segmentation approach using the proposed lazy random walk (LRW) algorithm in this paper. Our method begins with initializing the seed positions and runs the LRW algorithm on the input image to obtain the probabilities of each pixel. Then, the boundaries of initial superpixels are obtained according to the probabilities and the commute time. The initial superpixels are iteratively optimized by the new energy function, which is defined on the commute time and the texture measurement. Our LRW algorithm with self-loops has the merits of segmenting the weak boundaries and complicated texture regions very well by the new global probability maps and the commute time strategy. The performance of superpixel is improved by relocating the center positions of superpixels and dividing the large superpixels into small ones with the proposed optimization algorithm. The experimental results have demonstrated that our method achieves better performance than previous superpixel approaches. © 2013 IEEE. (33 refs.)Main Heading: Iterative methodsControlled terms: Algorithms - Image segmentation - Optimization - Random processes - TexturesUncontrolled terms: Better performance - commute time - Optimization algorithms - Probability maps - Random Walk - Super pixels - Superpixel segmentations - Texture measurementClassification Code: 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 921 Mathematics - 922.1 Probability Theory - 933 Solid State Physics

Database: Compendex

Application of FIR real-time filtering in fiber-optic current sensor

Li, Yuan Yuan1, 2; Xu, Jin Tao2; Cao, Hui2; Yang, Xiao Jun2 Source: Applied Mechanics and Materials, v 568-570, p 590-593, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.590;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 University of Chinese Academy of Sciences, China2 Xi'an Institute of Optics and Precision Mechanics, China

Abstract: When Fiber-Optic Current Sensor(FOCS) measures the grid's small current, FOCS's output contains large noise due to the environment and components' inherent noise, which results in lower accuracy. In order to improve the small current's accuracy, a system of signal processing base on FIR real-time filtering was adopted. This text introduced the window functions' features and filtering system aiming at the FOCS's output was proposed. This system can adjust filter coefficient conveniently according to the output's character. By the AC experiment under room temperature, the result proves that the SNR of FOCS's output signal is improved by filtering and the current error ratio meets 0.2s class. © (2014) Trans Tech Publications, Switzerland. (9 refs.)Main Heading: Fiber optic sensorsControlled terms: Signal processing - Signal to noise ratioUncontrolled terms: Error ratio - Fiber-optic current sensor - Filter coefficients - Filtering systems - Noise - Real time filtering - Room temperature - Window functionsClassification Code: 716.1 Information Theory and Signal Processing - 732.2 Control Instrumentation

Database: Compendex

Weak signal detection method in a stronger noise background

Wang, Jun1; Bai, Jian Ming2 Source: Applied Mechanics and Materials, v 568-570, p 260-264, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.260;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: When we use the laser auto collimation theodolite to measure the azimuth error angle of air target, the strong noise background reduces the spot imaging quality and seriously influences the measuring angle ability of the theodolite. In order to solve the problem, a photoelectric detection system used to detect the weak signal is designed based the correlation detection principle and the principle of correlation detection technology is introduced. We use Simulink software presenting a simulation to the detection system and do a feasibility analysis. Finally, it's proved that the photoelectric detection system could suppress the strong noise background, improve the SNR greatly and detect the weak signal effectively. © (2014) Trans Tech Publications, Switzerland. (8 refs.)Main Heading: Signal detectionControlled terms: Correlation methods - Photoelectricity - Signal to noise ratioUncontrolled terms: Correlation detection - Feasibility analysis - Laser signals - Noise - Photoelectric detection systems - Simulink software - SNR - Weak signal detectionClassification Code: 716.1 Information Theory and Signal Processing - 741.1 Light/Optics - 922.2 Mathematical Statistics

Database: Compendex

The camera lens design of 3D low light level color nightvision system

Li, Juan1, 2; Liu, Zhao Hui1; Mei, Chao1, 2 Source: Applied Mechanics and Materials, v 568-570, p 598-603, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.598;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'An institute of optics and precision mechanics of CAS, Xi'An, 710119, China2 University of Chinese Academy of Sciences, Beijing, 100049, China

Abstract: Two camera lenses for 3D low light level color night vision systemare designed in CODE V. The panchromatic sensitive camera lens works in a widespectral band 400nm-1000nm, yellow green-sensitive camera lens works in a band of400nm-600nm.The two camera lenses have same parameters, such as focal length 120mm,relative aperture 1/2, the field angle of 5.26 °. In the design of two camera lenses,we split and complex cooke triplet lens, the chromatic aberration is balanced byadding a binary diffractive surface. The results of design show that sensitivepanchromatic camera lens and yellow-green-sensitive camera lens, in the all fieldof view, when the Nyquist frequency is 77.5 (lp / mm), all MTF is larger than 0.6;the axial chromatic aberration of sensitive panchromatic camera lens is 0.056mm.Two camera lenses have good imaging performance. © (2014) Trans Tech Publications, Switzerland. (4 refs.)Main Heading: AberrationsControlled terms: Camera lenses - Color - Computer visionUncontrolled terms: Chromatic aberration - Color night vision - Diffractive surfaces - Imaging performance - Low light level - Night vision systems - Nyquist frequency - Wide spectralClassification Code: 741 Light, Optics and Optical Devices - 742.2 Photographic Equipment

Database: Compendex

Fuzzy PID control for fast-steering mirror system

Bai, Xue Jin1; Qiao, Yong Ming1 Source: Applied Mechanics and Materials, v 568-570, p 1026-1030, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.1026;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Fast-steering mirror system demands higher accuracy and fast responding speed to track targets, but the conventional PID controllers cannot meet the demands. Instead, the fuzzy PID control can greatly improve the capturing and tracking capacities to high-speed dynamic targets. So we apply the fuzzy-PID controller in the positioning loop of the stabilized system, not only improving the transient process of the control system and decreasing the overshoot, but also enhancing the accuracy of tracking stabilization and response. At the end, simulations were performed to test the effectiveness of this method through the MATLAB platform. © (2014) Trans Tech Publications, Switzerland. (6 refs.)Main Heading: Three term control systemsControlled terms: Mirrors - ModelsUncontrolled terms: ATP systems - Conventional pid - Fast-steering mirrors - Fuzzy - pid controls - Fuzzy PID controller - Simulation - Tracking capacity - Transient processClassification Code: 731.1 Control Systems - 741.3 Optical Devices and Systems - 902.1 Engineering Graphics

Database: Compendex

Schlieren confocal microscopy for phase-relief imaging

Xie, Hao1, 2; Jin, Dayong3; Yu, Junjie4; Peng, Tong1, 5; Ding, Yichen1; Zhou, Changhe4; Xi, Peng1 Source: Optics Letters, v 39, n 5, p 1238-1241, March 1, 2014

; ISSN: 01469592, E-ISSN: 15394794; DOI: 10.1364/OL.39.001238;

Publisher: Optical Society of AmericaAuthor affiliation: 1 Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China2 Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, United States3 Advanced Cytometry Labs, MQ Photonics Research Centre, Macquarie University, NSW 2109 Sydney, Australia4 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China5 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710068, China

Abstract: We demonstrate a simple phase-sensitive microscopic technique capable of imaging the phase gradient of a transparent specimen, based on the Schlieren modulation and confocal laser scanning microscopy (CLSM). The incident laser is refracted by the phase gradient of the specimen and excites a fluorescence plate behind the specimen to create a secondary illumination; then the fluoresence is modulated by a partial obstructor before entering the confocal pinhole. The quantitative relationship between the image intensity and the sample phase gradient can be derived. This setup is very easy to be adapted to current confocal setups, so that multimodality fluorescence/structure images can be obtained within a single system. © 2014 Optical Society of America. (16 refs.)Main Heading: Confocal microscopyControlled terms: Optics - Optoelectronic devicesUncontrolled terms: Confocal laser scanning microscopy - Confocal pinholes - Confocal setup - Image intensities - Incident laser - Microscopic techniques - Multi-modality - Phase-sensitiveClassification Code: 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Design of optical system for SG-III near backscatter diagnosis

Yan, Ya-Dong1; He, Jun-Hua1; Wang, Feng2; Zhang, Min1; Li, Shi-Bo1, 3 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 6, p 1469-1476, June 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142206.1469;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China3 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: After analysis the collecting methods of near backscatter light in laser fusion, a metal ellipsoidal mirror was proposed to collect the near backscatter light of SG-III laser facility. Then, the method to determine the parameters of ellipsoidal mirror was discussed. The mirror is composed of four pieces, which makes it entering into the target chamber easily. The mirror is made of super hard aluminum, and a triangular weight reducing slot is designed on the back of the mirror to reduce its weight and improve its mechanical stability. The overall structure of the optical system was introduced, and the light gathering performance was simulated using optical software. The key issues in ellipsoidal mirror design, including material selection and structure selection, were analyzed. In order to avoid rework, a semiconductor laser array was developed specially to test the surface in design processing. The stray lights in the system were analyzed, physical isolation, optical absorbing and optical filters were used to control them. The ring ellipsoidal mirror with a weight of 48 kg has an outside diameter of 1200 mm, an inside diameter of 400 mm, the maximum off-axis magnitude of 1411 mm, and the maximum thickness of 67 mm. The image spot size is about 1.2 mm within a field of view 5 mm. This system mentioned above can offer a reference for near backscatter diagnostic in inertial confinement fusion research. (17 refs.)Main Heading: Laser mirrorsControlled terms: Backscattering - Laser fusion - Light sources - Mirrors - Optical design - Optical systemsUncontrolled terms: Ellipsoidal mirrors - Material selection - Maximum thickness - Metal mirror - Physical isolation - Point light source - Semiconductor laser arrays - Structure selectionClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.9 Laser Applications

Database: Compendex

Giant Kerr nonlinearity induced by tunneling in triple quantum dot molecules

Tian, Si-Cong1; Wan, Ren-Gang2; Tong, Cun-Zhu1; Ning, Yong-Qiang1; Qin, Li1; Liu, Yun1 Source: Journal of the Optical Society of America B: Optical Physics, v 31, n 7, p 1436-1442, July 1, 2014

; ISSN: 07403224; DOI: 10.1364/JOSAB.31.001436;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Luminescence and Application, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: A scheme for giant enhancement of the Kerr nonlinearity in linear triple quantum dot molecules is proposed. In such a system, the tunneling-induced transparency window obtained in double quantum dot molecules splits into two windows, due to the coupling with the third quantum dot. And most important, the Kerr nonlinearity can be enhanced by several orders of magnitude, compared with that generated in double quantum dot molecules. With proper detuning of the tunneling, giant Kerr nonlinearity accompanied by vanishing absorption can be realized, which opens the possibility to enhance self-phase modulation in tunneling controllable semiconductor nanostructures under conditions of low light levels. Quantitative analysis shows that the giant Kerr nonlinearity is attributed to the interacting double dark resonances induced by the tunneling between the triple quantum dots, therefore no extra laser fields are required. © 2014 Optical Society of America. (43 refs.)Main Heading: Semiconductor quantum dotsControlled terms: Molecules - Optical Kerr effectUncontrolled terms: Dark resonance - Double quantum dots - Kerr nonlinearity - Low light level - Orders of magnitude - Semiconductor nanostructures - Triple quantum - Tunneling-induced transparenciesClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 931.3 Atomic and Molecular Physics

Database: Compendex

Experimental study of femtosecond laser written waveguide in Yb3+:phosphate glass and waveguide laser

Bai, Jing1, 2; Long, Xuewen1, 2; Liu, Xin1, 2; Zhao, Wei1; Hui, Rongqing1; Cheng, Guanghua1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 4, April 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0432003; Article number: 0432003;

Abstract: Femtosecond laser with repetition rate of 1 kHz, central wavelength of 800 nm and pulse width of 120 fs is used to write waveguides in Yb3+:phosphate glass, then near-field modes of waveguide written by different laser parameters are measured. The refractive index changes in the written region and mode field diameter as functions of writing parameters (scanning speed and writing pulse energy) are obtained, which show the writing window of waveguide formation in Yb3+:phosphate glass. The fluorescence spectra of the waveguide and the bulk material are tested and compared. Experimental results show that there is no difference in the fluorescence spectra of the waveguide and the bulk material with 20× objective lens, scanning speed of 20 μm/s and pulse energy of 1.8 μJ, the mode field diameter is 20 μm injected at 976 nm, the refractive index change is 2.7×10-4, and the fluorescence properities keep the same after femtoscecond laser effect. Stable and continuous wave (CW) Yb3+:doped waveguide laser is achieved in a Fabry-Perot cavity configuration by using dichronic mirror and 2% output coupler. An output with power of 2.9 mW at a central wavelength of 1031 nm is obtained. (26 refs.)Main Heading: Laser mirrorsControlled terms: Fluorescence - Glass - Integrated optics - Materials handling equipment - Optical waveguides - Semiconductor quantum wells - Ultrashort pulses - Waveguides - YtterbiumUncontrolled terms: Central wavelength - Fabry-Perot cavity - Fluorescence spectra - Laser technique - Mode field diameter - Refractive index changes - Waveguide formation - Waveguide lasersClassification Code: 547.2 Rare Earth Metals - 691.1 Materials Handling Equipment - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 812.3 Glass

Database: Compendex

Performance of diode-pumped Tm3+:Sc<inf>2</inf>SiO<inf>5</inf> crystal passively Q-switched 2 μm laser

Li, Yaqi1; Liu, Jie1, 2; Zhu, Hongtong1; Zheng, Lihe3; Su, Liangbi3; Xu, Jun3; Wang, Yonggang4 Source: Optics Communications, v 330, p 151-154, November 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.05.049;

Publisher: ElsevierAuthor affiliation: 1 College of Physics and Electronics, Shandong Normal University, Jinan, 250014, China2 State Key Laboratory of Crystal Material, Shandong University, Jinan 250100, China3 Key Laboratory of Transparent and Opto-Functional Advanced Inorganic Materials, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201800, China4 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: A diode-pumped passively Q-switched Tm3+:Sc<inf>2</inf>SiO <inf>5</inf> laser with a single-walled carbon nanotube saturable absorber is demonstrated for the first time. The maximum average output power of 189 mW has been achieved at 1970 nm under an absorbed pump power of 4 W. The minimum pulse width of 442 ns was obtained at a repetition rate of 55.6 kHz, corresponding to the highest peak power of 7.7 W and single pulse energy of 3.4 μJ, respectively. © 2014 Elsevier B.V. (26 refs.)Main Heading: Pumping (laser)Controlled terms: Q switched lasers - Q switching - Saturable absorbers - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Absorbed pump power - Average output power - Diode-pumped - Minimum pulse widths - Passively Q-switched - Passively Q-switched lasers - Single pulse energy - Single-walled carbon nanotube saturable absorbersClassification Code: 744.1 Lasers, General - 744.8 Laser Beam Interactions - 761 Nanotechnology

Database: Compendex

Fusion of multichannel local and global structural cues for photo aesthetics evaluation

Zhang, Luming1; Gao, Yue2; Zimmermann, Roger1; Tian, Qi3; Li, Xuelong4 Source: IEEE Transactions on Image Processing, v 23, n 3, p 1419-1429, March 2014

; ISSN: 10577149; DOI: 10.1109/TIP.2014.2303650; Article number: 6728663;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Computing, National University of Singapore, Singapore 119613, Singapore2 Tsinghua University, Beijing 100086, China3 Department of Computer Science, University of Texas, San Antonio, TX 78249, United States4 Center for OPTical IMagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Photo aesthetic quality evaluation is a fundamental yet under addressed task in computer vision and image processing fields. Conventional approaches are frustrated by the following two drawbacks. First, both the local and global spatial arrangements of image regions play an important role in photo aesthetics. However, existing rules, e.g., visual balance, heuristically define which spatial distribution among the salient regions of a photo is aesthetically pleasing. Second, it is difficult to adjust visual cues from multiple channels automatically in photo aesthetics assessment. To solve these problems, we propose a new photo aesthetics evaluation framework, focusing on learning the image descriptors that characterize local and global structural aesthetics from multiple visual channels. In particular, to describe the spatial structure of the image local regions, we construct graphlets small-sized connected graphs by connecting spatially adjacent atomic regions. Since spatially adjacent graphlets distribute closely in their feature space, we project them onto a manifold and subsequently propose an embedding algorithm. The embedding algorithm encodes the photo global spatial layout into graphlets. Simultaneously, the importance of graphlets from multiple visual channels are dynamically adjusted. Finally, these post-embedding graphlets are integrated for photo aesthetics evaluation using a probabilistic model. Experimental results show that: 1) the visualized graphlets explicitly capture the aesthetically arranged atomic regions; 2) the proposed approach generalizes and improves four prominent aesthetic rules; and 3) our approach significantly outperforms state-of-the-art algorithms in photo aesthetics prediction. © 2013 IEEE. (45 refs.)Main Heading: Quality controlControlled terms: Algorithms - Image processingUncontrolled terms: aesthetic evaluation - Conventional approach - Embedding algorithms - Multi-channel - Probabilistic modeling - Spatial arrangements - State-of-the-art algorithms - structural cuesClassification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 913.3 Quality Assurance and Control - 921 Mathematics

Database: Compendex

Investigation of a terahertz-wave parametric oscillator using LiTaO <inf>3</inf> with the pump-wavelength tuning method

Sun, Bo1; Bai, Xianpeng1; Liu, Jinsong2; Yao, Jianquan3 Source: Laser Physics, v 24, n 3, March 2014

; ISSN: 1054660X, E-ISSN: 15556611; DOI: 10.1088/1054-660X/24/3/035402; Article number: 035402;

Publisher: Maik Nauka-Interperiodica PublishingAuthor affiliation: 1 Institute of Photonics and Photonic Technology, Northwest University, Xi'an 710069, China2 Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China3 College of Precision and Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China

Abstract: We investigate theoretically the performance of a terahertz parametric oscillator (TPO) using LiTaO<inf>3</inf> (LT) with the pump-wavelength tuning method. The frequency tuning accuracy of the LT-TPO is potentially superior to that of a TPO using LiNbO<inf>3</inf> (LN) under the same conditions. The variation of the radiation angle of THz waves coupled from the Si prism of the LT-TPO is up to about 20° lower than that for the LN-TPO for a pump-wavelength tuning range of 0.4-1.6 μm. Although the THz-wave parametric gain characteristics of LiTaO<inf>3</inf> are somewhat unsatisfactory compared with those of LiNbO<inf>3</inf>, the LT-TPO with pump-wavelength tuning can still show potential for high-performance operation, with the excellent optical properties of the LiTaO<inf>3</inf>. © 2014 Astro Ltd. (11 refs.)Main Heading: Parametric oscillatorsControlled terms: Condensed matter physics - Terahertz wavesUncontrolled terms: Frequency-tuning - High-performance operation - Parametric gain - Polariton scattering - Terahertz parametric oscillators - Terahertz-wave parametric oscillators - Tuning methodClassification Code: 711 Electromagnetic Waves - 713.2 Oscillators - 931 Classical Physics; Quantum Theory; Relativity - 933 Solid State Physics

Database: Compendex

Object-aware power line detection using color and near-infrared images

Luo, Xiaoyan1; Zhang, Jun1; Cao, Xianbin1; Yan, Pingkun2; Li, Xuelong2 Source: IEEE Transactions on Aerospace and Electronic Systems, v 50, n 2, p 1374-1389, April 2014

; ISSN: 00189251; DOI: 10.1109/TAES.2013.120444; Article number: 6850161;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronics and Information Engineering, Beihang University, National Key Laboratory of CNS, 100191 Beijing, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xían, 61, China

Abstract: Vision-based power line detection (PLD) is an important yet challenging problem in low-altitude flight. Different from the traditional PLD methods, which only aim at line information, we propose a novel object-aware PLD method to obtain better detection performance. A new definition of power line is first proposed to present its object-aware properties; and then a cascaded PLD scheme is devised with line detection, region filtration, and object validation based on corresponding image cues in joint color (RGB) and near-infrared (NIR) images. Considering that the primary goal of PLD is to capture all potential information and decrease the false negatives, we first treat the universal line shape in pixel from joint RGB-NIR images as a basic feature to explore general line candidates. To further pick out the accurate regions occupied by power lines, on the one hand we filter the false candidates based on the region-based intensity of special material characteristics in NIR, and on the other hand we validate the power lines according to the color features in RGB. The experiments demonstrate the advantages of our proposed method in three aspects: good detection accuracy, high true detection rate, and low false detection rate. © 2014 IEEE. (39 refs.)Main Heading: Infrared devicesControlled terms: Color - Electric lines - Infrared imagingUncontrolled terms: Detection accuracy - Detection performance - Detection rates - False detections - False negatives - Low-altitude flight - Material characteristics - Near-infrared imagesClassification Code: 706.2 Electric Power Lines and Equipment - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Sub-100 ns passively Q-switched Nd:LuAG laser with multi-walled carbon nanotube

Chen, X.T.1; Zhao, S.Z.1; Zhao, J.1; Yang, K.J.1; Li, G.Q.1; Li, D.C.1; Qiao, W.C.1; Li, T.1; Zhang, H.J.1; Feng, T.L.1; Xu, X.D.2; Zheng, L.H.2; Xu, J.2; Wang, Y.G.3; Wang, Y.S.3 Source: Optics and Laser Technology, v 64, p 7-10, December 2014

; ISSN: 00303992; DOI: 10.1016/j.optlastec.2014.04.019;

Publisher: Elsevier LtdAuthor affiliation: 1 School of Information Science and Engineering, Shandong University, Shandong 250100, China2 Key Laboratory of Material Science and Technology for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We report the first demonstration of a diode-pumped passively Q-switched Nd:LuAG laser with a multi-walled carbon nanotube (MWCNT) as saturable absorber. A maximum average output power of 844 mW and pulses as short as 78 ns under a repetition rate of about 100 kHz were generated. A MWCNT Q-switched Nd:YAG laser was comparatively investigated, in comparison with which the Nd:LuAG laser showed lower threshold absorbed pump power and higher pulse energy, indicating a better energy storage ability of Nd:LuAG crystal than Nd:YAG. © 2014 Elsevier Ltd. (16 refs.)Main Heading: Neodymium lasersControlled terms: Multiwalled carbon nanotubes (MWCN) - Pumping (laser) - Q switching - Saturable absorbersUncontrolled terms: Absorbed pump power - Average output power - MWCNT - Passive Q-switching - Passively Q-switched - Q switched Nd:YAG laser - Repetition rate - Storage abilitiesClassification Code: 744 Lasers - 761 Nanotechnology

Database: Compendex

Flux-solvothermal preparation of dispersible LiLa<inf>0.4</inf>Nd <inf>0.6</inf>(PO<inf>3</inf>)<inf>4</inf> microcrystals with regular morphology and superior fluorescence

Wang, Zhongyue1; Duan, Weikuan1; Cui, Xiaoxia3; Liang, Chen1; Zheng, Ruilin2; Wei, Wei2, 3 Source: Journal of Materials Chemistry C, v 2, n 20, p 4012-4018, May 28, 2014

; ISSN: 20507534, E-ISSN: 20507526; DOI: 10.1039/c3tc32438a;

Publisher: Royal Society of ChemistryAuthor affiliation: 1 Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023, China2 School of Optoelectronic Engineering, Nanjing University of Posts and Telecommunications (NUPT), Nanjing 210023, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an 710119, China

Abstract: A flux-solvothermal method was used to grow a type of novel dispersible LiLa<inf>0.4</inf>Nd<inf>0.6</inf>(PO<inf>3</inf>)<inf>4</inf> microcrystals with high Nd3+ ions concentration of 2.63 × 1021 cm-3 and excellent fluorescence properties for the first time. By optimizing experimental conditions, microcrystals with sizes in the region of 1.5-5 μm, a strong emission intensity and long lifetime of 107 μs were obtained. The results show that their transparent dispersion in the mixed solvents of DMSO and CHBr<inf>2</inf>CHBr<inf>2</inf> had a strong absorption at 800 nm, low solvent quenching ratio of 6.5%, high quantum yield of 32.17% and large emission cross section of 4.39 × 10-20 cm2 when the Nd3+ ions concentration is 1 × 1020 cm -3, which imply the microcrystals are of potential application in transparent glass-ceramics, dispersion amplifiers and lasers. © 2014 the Partner Organisations. (30 refs.)Main Heading: MicrocrystalsControlled terms: Dispersions - Fluorescence - Glass ceramicsUncontrolled terms: Emission cross section - Emission intensity - Experimental conditions - Fluorescence properties - Long lifetime - Mixed solvent - Strong absorptions - Transparent glass ceramicsClassification Code: 741.1 Light/Optics - 744 Lasers - 761 Nanotechnology - 812.1 Ceramics - 951 Materials Science

Database: Compendex

Theoretical and experimental investigations of a nanotube-mode-locked stretched-pulse fiber laser

Guo, J.1 Source: Laser Physics, v 24, n 6, June 2014

; ISSN: 1054660X, E-ISSN: 15556611; DOI: 10.1088/1054-660X/24/6/065104; Article number: 065104;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We report the generation of stretched pulses in a passively mode-locked fiber laser based on a single-wall carbon nanotube saturable absorber. The spectral bandwidth and pulse duration of the single stretched pulse are &sim;25nm and &sim;1.43ps, respectively. By increasing the pump power and adjusting the polarization state, bound-state stretched pulses are delivered from the fiber laser. The pulse-pulse separation and wavelength spacing of the bound-state pulses are &sim;7.8ps and &sim;1nm, respectively. Numerical simulations reproduce the experimental results and agree well with the experimental observations. © 2014 Astro Ltd. (46 refs.)Main Heading: Pulse generatorsControlled terms: Fiber lasers - Locks (fasteners) - Mode-locked fiber lasers - Nanotubes - Optical pumping - Passive mode locking - Saturable absorbers - Ultrafast lasersUncontrolled terms: Experimental investigations - Fiber optics amplifiers and oscillators - Passively mode-locked fiber lasers - Polarization state - Pulse durations - Spectral bandwidth - stretched pulse - Wavelength spacingClassification Code: 601.3 Mechanisms - 713.4 Pulse Circuits - 741.1 Light/Optics - 741.1.2 Fiber Optics - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology

Database: Compendex

Design and implementation of integrated diagnostic beam fast automatic alignment system

Wang, Zheng-Zhou1, 2; Wang, Wei1, 2; Hu, Bing-Liang1; Wang, Wei1; Cao, Shi-Kang1; Li, Dong-Jian1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 5, May 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144305.0512005; Article number: 0512005;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100039, China

Abstract: Parallel processing, fast convergent motor model and characteristic points extracted from the smallest outer circle were proposed to design the automatic alignment system, which can integrated diagnostic fast automatic alignment. First, all the alignment steps were executed in parallel and serial-parallel mode, and the important steps were reduced to unit alignment model. Second, the mathematical model for fast automatic alignment was used and the fast convergent algorithm of the unit alignment model was implemented. Finally, according to the characteristics of small laser spot, which contrast was low, distribution was asymmetrical, spot was not complete, the 100 characteristic points were extracted from the smallest outer circle and any two points distance was maximal, then a new method of circle fitting using least square method to calculate small laser spot center was proposed. Through the improvement of the above three aspects, alignment time reduced from 40 minutes to 8 minutes before the three aspects were optimized, the error of small laser spot centre is less than 2 pixels, and meet the experiment requirements. (15 refs.)Main Heading: AlignmentControlled terms: Least squares approximations - Mathematical modelsUncontrolled terms: Automatic alignment - Characteristic point - Circle fitting - Least square methods - Motor models - The smallest outer circleClassification Code: 601.1 Mechanical Devices - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

Study of the key aspects in developing kW-level diode lasers for solid state laser pumping

Li, Xiaoning1; Wang, Jingwei1; Cai, Wanshao1; Hao, Bei1; Hou, Dong1; Liu, Hui1; Zhang, Pu1; Liu, Xingsheng1 Source: Proceedings - 2014 International Conference Laser Optics, LO 2014, 2014, Proceedings - 2014 International Conference Laser Optics, LO 2014; ISBN-13: 9781479938858; DOI: 10.1109/LO.2014.6886212; Article number: 6886212; Conference: 2014 International Conference Laser Optics, LO 2014, June 30, 2014 - July 4, 2014;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics of China Academy of Sciences, Focuslight Technologies Co., Ltd., China

Abstract: In this paper, the key aspects, such as thermal management, thermal stress analysis and management, processes development, failure analysis and reliability evaluation, in developing kW-level diode lasers for solid state laser pumping are studied. © 2014 IEEE.Main Heading: Solid state lasersControlled terms: Optical pumping - Semiconductor lasers - Stress analysisUncontrolled terms: kW-level - Reliability Evaluation - Solid state laser pumping - StackClassification Code: 421 Strength of Building Materials; Mechanical Properties - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 951 Materials Science

Database: Compendex

Design and fabrication of cyclic-olefin copolymer based hollow-core microstructured terahertz fiber

Ji, Jiangjun1; Kong, Depeng1; Ma, Tian1; He, Xiaoyang2; Chen, Qi2; Wang, Lili1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 6, p 1909-1913, June 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Institute of Electronic Engineering, China Academy of Engineering Physics, Mianyang 621900, China

Abstract: A hollow-core porous microstructured terahertz fiber based on Topas cyclic-olefin polymer (COC) was designed and manufactured. The loss characteristics of an optical fiber with outer diameter 10 mm was simulated using comsol software in the 0.2-1.5 THz band. There are several low-loss bands in the 0.85 -1.5 THz, and there are three windows in which the loss is lower than 3 dB/m in the 0.85 -1.1 THz band, the loss is about 0.208 dB/m especially in the 0.99 THz. By comparing the loss characteristics of the fiber with core diameter of 3 mm, 4.8 mm and 6 mm in 0.8-1.5 THz band, the loss was reduced with increasing the diameter. The outer diameter of designed THz fiber was enlarged to 7 cm, and a dedicated mold was designed for manufacturing preform. A 22 cm long THz fiber preform with a standard structure and smooth surface was manufactured by the hot extrusion molding method. Finally, through the laboratory's unique draw tower, the terahertz fiber of the core diameter of 3 mm, 4.8 mm and 6 mm were manufactured. The loss analysis result show that the average loss of the fiber with core diameter of 6mm is 2.175 dB/m in 1.27 THz and it is near the theoretical loss (1.95 dB/m). (11 refs.)Main Heading: FibersControlled terms: Olefins - Optical fiber fabrication - Optical fibers - PreformingUncontrolled terms: Antiresonant - Hollow-core waveguides - Loss characteristics - Tera Hertz - Topas COCClassification Code: 535.2.2 Metal Forming Practice - 741.1.2 Fiber Optics - 804.1 Organic Compounds - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

Optimized design of automatic panoramic images mosaic

Yang, Lei1; Cao, Jianzhong1; Tang, Linao1; Gao, Bo1; Wang, Hua1; Guo, Huinan1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 985-990, March 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: An optimized algorithm of automatic panoramic image mosaic was presented based on time and frequency domains. Firstly, the improved phase correlation method was used to sort the panoramic image sequence automatically and then determine the overlap region. In order to reduce the false match rate of the corner, the brightness of the overall image was adjusted automatically according to the overlap region's pixel mean. Then, an improved Harris operator was adopted to extract corners (with no need to set threshold value manually), the initial feature points pairs were obtained by the bidirectional greatest correlative coefficient and the false feature point pairs were rejected by RANSAC algorithm. Finally, the nonlinear smoothing algorithm was adopted to fuse the overlap regions of the image. The experimental results show that optimization algorithm is simple and effective in the sorting process. Compared with the existing algorithm, the optimization algorithm proposed at present makes a great progress in the success rate and the efficiency in the matching and extracting process of feature points. The stitched image is with great clarity, soundness and stitching accuracy. (8 refs.)Main Heading: Image matchingControlled terms: Algorithms - Image fusion - OptimizationUncontrolled terms: Automatic sequencing - Corner detection - Correlative coefficients - Image mosaic - Optimization algorithms - Phase correlation - Phase correlation method - Time and frequency domainsClassification Code: 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 921 Mathematics - 921.5 Optimization Techniques

Database: Compendex

Measuring principle of vertical target density based on single linear array CCD camera

Dong, Tao1, 2; Hua, Dengxin1; Li, Yan1; Ni, Jinping2 Source: Optik, v 125, n 1, p 176-178, January 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.07.006;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 School of Mechanical and Precision Instrument Engineering, Xi'An University of Technology, Xi'an 710048, China2 School of Opto-electronic Engineering, Xi'An Technological University, Xi'an 710032, China

Abstract: In consideration of the complexity and the high cost of the dual CCD intersection vertical target when it is used indoor. A novel measuring principle of one linear array CCD camera vertical target is presented. One low-power semiconductor sector-like laser with projection board is used to be the lamp-house of the CCD camera. The detection light screen of the CCD camera and the laser lamp-house are adjusted to same plane. When the projectile through the detection light screen, it blocks the part light of the laser and leaves a shadow of projectile on the board. The shadow and its coordinate are acquired and calculated by the CCD camera and computer, and the projectile coordinate of X and Y can be gotten through image processing and further calculation. The measuring principle and the formulas are given, and the measuring error is analyzed. The result indicates that the coordinate error of X and Y less than 1.5 and 2.2 mm, respectively, when the detection light screens is 1 m × 1 m, The principle presented has the advantages that measurement principle is simple, low cost and easy engineering. © 2013 Elsevier GmbH. (9 refs.)Main Heading: CCD camerasControlled terms: Image processing - Power electronics - ProjectilesUncontrolled terms: High costs - Linear array CCD - Low costs - Low Power - Measuring errors - Vertical targetsClassification Code: 654 Rockets and Rocket Propulsion - 714.2 Semiconductor Devices and Integrated Circuits - 715.2 Industrial Electronic Equipment - 741 Light, Optics and Optical Devices

Database: Compendex

Multi-cue based tracking

Wang, Qi1; Fang, Jianwu2; Yuan, Yuan2 Source: Neurocomputing, v 131, p 227-236, May 5, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.10.021;

Abstract: Visual tracking is a central topic in computer vision. However, the accurate localization of target object in extreme conditions (such as occlusion, scaling, illumination change, and shape transformation) still remains a challenge. In this paper, we explore utilizing multi-cue information to ensure a robust tracking. Optical flow, color and depth clues are simultaneously incorporated in our framework. The optical flow can get a rough estimation of the target location. Then the part-based structure is adopted to establish the precise position, combining both color and depth statistics. In order to validate the robustness of the proposed method, we take four video sequences of different demanding situations and compare our method with five competitive ones representing state of the arts. Experiments prove the effectiveness of the proposed method. © 2013 Elsevier B.V. (43 refs.)Main Heading: Optical flowsControlled terms: Computer applications - Computer vision - Neural networks - Surface dischargesUncontrolled terms: Depth - Extreme conditions - Illumination changes - Kinect - Precise position - Rough estimation - Shape transformation - Target locationClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 723.4 Artificial Intelligence - 723.5 Computer Applications - 741.1 Light/Optics

Database: Compendex

Detail enhancement for high dynamic range images rendering based on multi-level decomposition

Wang, Hua1; Zhang, Hui1; Cao, Jian Zhong1; Zhou, Zuo Feng1; Yang, Lei1; Zhao, Xiao Dong1; Ren, Long1 Source: Applied Mechanics and Materials, v 543-547, p 2600-2604, 2014, Vehicle, Mechatronics and Information Technologies II

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350606; DOI: 10.4028/www.scientific.net/AMM.543-547.2600; Conference: International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2014, February 19, 2014 - February 20, 2014; Sponsor: INTIEA Information and Engineering; Scientific.Net; Trans Tech publications inc.; National Institute of Technology Rourkela; Universitatea Politehnica Din Bucuresti; et al;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China

Abstract: Various tone reproduction operators have been proposed to display high dynamic range images on low dynamic range (LDR) devices. Many recent computational photography techniques decompose an image into a piecewise smooth base layer, containing large scale variations in intensity, and a residual detail layer capturing the smaller scale details in the image. In these techniques, it's important to control the scale of the extracted details and it is often needed to manipulate details in order to avoid the appearance of visual artifacts. In this paper, a new method is proposed to preserve details for high dynamic range images tone reproduction using multi-level image decomposition. We show that current base-detail decomposition techniques, based on the bilateral filter, are limited in their ability to extract detail at arbitrary scales. Thus, we achieve detail enhancement by applying the bilateral filter iteratively, and this process is called multi-level decomposition. By minimizing the proposed energy function, we can choose the proper decomposition level. Simulation results demonstrate that the proposed method can acquire better visual quality in detail enhancement while make the base smoothness. © (2014) Trans Tech Publications, Switzerland. (14 refs.)Main Heading: Iterative methodsControlled terms: Color image processing - Color photography - Display devices - Information technologyUncontrolled terms: Computational photography - Decomposition level - Decomposition technique - Detail enhancement - High dynamic range - High dynamic range images - Image decomposition - Tone mappingClassification Code: 722.2 Computer Peripheral Equipment - 741.1 Light/Optics - 742.1 Photography - 903 Information Science - 921.6 Numerical Methods

Database: Compendex

All-fiber laser simultaneously delivering multi-wavelength solitons

Yun, L.1 Source: Optics Communications, v 322, p 61-65, July 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.02.007;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: All-fiber triple-wavelength laser mode-locked by a nonlinear amplifier loop mirror is proposed and demonstrated experimentally for the first time to author's best knowledge. By means of chirped fiber Bragg gratings in the intra-cavity and extra-cavity, three kinds of solitons with different wavelengths are simultaneously delivered from the proposed laser. The central wavelengths of solitons are 1539.5, 1549.5, and 1559.5 nm with the pulse durations of 6.2, 4.2, and 5 ps and the spectral bandwidths of 0.4, 0.7, and 0.5 nm, respectively. The experimental observations show that the all-fiber triple-wavelength laser is very stable in the long-term operation and is convenient for practical applications. © 2014 Elsevier B.V. (48 refs.)Main Heading: SolitonsControlled terms: Fiber lasers - WavelengthUncontrolled terms: All-fiber lasers - Central wavelength - Chirped fiber Bragg grating - Mode cocking - Nonlinear amplifier - Pulse durations - Spectral bandwidth - Triple wavelengthsClassification Code: 711 Electromagnetic Waves - 741.1.2 Fiber Optics - 931.3 Atomic and Molecular Physics

Database: Compendex

Power line detection from optical images

Song, Biqin1, 2; Li, Xuelong1 Source: Neurocomputing, v 129, p 350-361, April 10, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.09.023;

Publisher: ElsevierAuthor affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China2 Graduate University of the Chinese Academy of Science, Beijing 100049, China

Abstract: Image-based power line detection is highly important for threat avoidance when the aerial vehicles fly in low altitude. However, it is very challenging for the requirements of high detection rates, low false alarms and real-time application. In this paper, a sequential local-to-global power line detection algorithm is proposed. In the local criterion, a line segment pool is detected by morphological filtering an edge map image, which is computed based on matched filter (MF) and first-order derivative of Gaussian (FDOG). It results in over detection to guarantee high detection rates. In the next global criterion, grouping the line segments into whole power lines is formulated as a graph-cut model based on graph theory. The principal advantage of the proposed algorithm is that it can detect not only the straight power lines but also the curve ones. Experimental results demonstrate that the algorithm has good performances both in detection accuracy and in processing time. © 2013 Elsevier B.V. (34 refs.)Main Heading: Electric linesControlled terms: Algorithms - Geometrical optics - Graph theory - Graphic methods - Image segmentation - Lakes - Matched filtersUncontrolled terms: First-order derivative - Graph-cut models - High detection rate - Line segment - Morphological filtering - Power lines - Real-time application - Threat avoidanceClassification Code: 921 Mathematics - 741.1 Light/Optics - 723.5 Computer Applications - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory - 723 Computer Software, Data Handling and Applications - 703.2 Electric Filters - 407 Maritime and Port Structures; Rivers and Other Waterways - 706.2 Electric Power Lines and Equipment

Database: Compendex

PST research and measurement of lunar-based optical telescope stray light

Xu, Liang1, 2; Zhao, Jianke1; Xue, Xun1; Zhou, Yan1; Liu, Feng1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 4, p 1289-1295, April 2014; Language: Chinese

; ISSN: 10072276;

Abstract: To verify suppression capability of the stray light of the lunar-based optical telescope (LOT), its stray light rejection ratio of glare shield out of field range by point source transmittance on ground was tested, and assessing its stray light rejection ratio with PST of optical system diversity angle of offaxis. The new test method of PST breaks through the tradition method of stray light, using a new method that is combining high degree of accuracy star simulator with EMCCD, guaranteeing that the detector has large dynamic region within its linear range, and the dynamic range is 1012. It could satisfy the indexing demand that the PST testing result is 10-7 (at 22°angle of off-axis). This test method could objectively and directly reflect the stray light rejection ratio of glare shield. The testing uncertainty of PST is above 60%, it will exceed the testing precision of classical stray light testing method. Moreover, discussing the improving method, the target PST testing result will reach 10-12. Last it verify the PST of LOT catering design demand with the experiment that it test stray light rejection ratio of glare shield. (12 refs.)Main Heading: Stray lightControlled terms: Glare - Optical systems - Optical telescopes - TestingUncontrolled terms: Design demands - Dynamic region - High degree of accuracy - Lunar-based optical telescopes - Off-axis - Point sources - Stray light rejection - Stray light testingClassification Code: 423.2 Non Mechanical Properties of Building Materials: Test Methods - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Optimal design of a new type space laser communication optical system

Yan, Pei-Pei1; Deng, Xiao-Guo1; Li, Gang1; Liu, Kai1; Duan, Jing1; Shan, Qiu-Sha1; Jiang, Kai1; Zhang, Yu1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9521, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628416527; DOI: 10.1117/12.2185077; Article number: 95211V; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics 2014, August 10, 2014 - August 15, 2014; Sponsor: Chinese Society of Astronautics;

Publisher: SPIEAuthor affiliation: 1 Photoelectric Measurement and Control Technology Research Department, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy Sciences, Xi'an, China

Abstract: A design of a laser communications optical system with high transmitting and receiving performance is given. The traditional on-axis Cassegrain optical antenna has the default that the transmitting and receiving power decreased greatly because of the obscuration of the secondary mirror. Considering that the eccentric-pupil Cassegrain optical antenna is designed. The optical antenna system in transceiver has been designed by means of CODEV software. It improves the efficiency of transmitting and receiving power effectively. Its properties have been analyzed, such as gain, image quality, and transmission efficiency. Meanwhile, the materials of optical elements have been analyzed. The power decline curve has been obtained by means of the detailed analysis of antenna system in partial axis situation. The system includes transmitter channel, receiving channel and experiment channel. It can realize the functions of transmitter-receiver isolation and multi-light ways using dichroic mirrors and beam splitting prisms. The system volume and weight are reduced greatly. The complexity of conventional laser communication system is reduced enormously at the same time. It has important reference significance and application value. © 2015 SPIE. (7 refs.)Main Heading: Optical communicationControlled terms: Antennas - Design - Integrated optics - Mirrors - Optical instruments - Optical links - Optical systems - TransmittersUncontrolled terms: Cassegrain optical antennas - Conventional lasers - Eccentric-pupil system - Optical antennae - Space laser communication - Space optical communication - Transmission efficiency - Transmitter channelsClassification Code: 408 Structural Design - 716 Telecommunication; Radar, Radio and Television - 717.1 Optical Communication Systems - 741.3 Optical Devices and Systems

Database: Compendex

Fast circle detection based on improved randomized Hough transform

Shi, Dongchen1; Zhang, Bo2; Wang, Ning3 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9285, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413601; DOI: 10.1117/12.2068644; Article number: 92850H; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Smart Structures and Materials for Manufacturing and Testing, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Electronic and Information Engineering, Xi'an University of Technology, Xi'an, China2 Electronic and Information Engineering, East University of HeiLongJiang, Ha'er Bin, China3 Xi'An Institute of Optics and Precision Mechanics of CAS 710119, China

Abstract: To solve the problem of a large amount of invalid sample and accumulations yielded by random sampling when randomized hough transform (RHT) is used to detect circles in complex images processing, an new improved arithmetic for circle detection is developed in this paper. It not only uses gradient direction information to determine whether the three sampling points should be accumulated or not, but also uses the regular hexagon window to narrow the searching range of pixels to improve the operating speed. The problem of invalid sampling and accumulations and multi-circle detection is well solved. The experiment results show that this algorithm has higher speed, smaller storage and better detection performance. (4 refs.)Main Heading: Feature extractionControlled terms: Hough transforms - Image processing - Manufacture - Materials testing - Optical data processingUncontrolled terms: Circle detection - Detection performance - Gradient direction - Operating speed - Randomized Hough transform - Regular hexagon - Sampling points - useless accumulationClassification Code: 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 537.1 Heat Treatment Processes - 716 Telecommunication; Radar, Radio and Television - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921.3 Mathematical Transformations - 951 Materials Science

Database: Compendex

Dynamics analysis on adhesive bonds of tilt mirror

Cao, Shang1, 2; Ruan, Ping1; Wang, Chao1, 2; Xu, Guangzhou1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2068441; Article number: 92800W; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Adhesive bonding technology has been widely applied in the field of space remote sensing. In order to make the adhesive bonds connecting the mirror and the fixed structures in a satellite launch or operation of dynamic environment without damage, the finite element model of the tilt mirror is essential to be established for dynamic analysis, as well as the experimental verification. There are detailed model and the equivalent stiffness model on the adhesive bonds. The modal, frequency response, random vibration and shock response are analyzed through the detailed model of the bonds. The stress of the three point mirror bonds is compared with the six point support mirror. The mechanics experiment is carried out based on the dynamics analysis. The results of calculation demonstrates that the impact of frequency response and random vibration on adhesive bonds is relatively little, while the impact of the shock response is large. The experimental verification shows that the stress of bonds with three points support mirror under shock response exceeds the shear strength, which leads to the separation of the mirror and the fixed structure and the improved six point support mirror is satisfied to the requirements. The dynamics analysis on adhesive bonds of tilt mirror makes sense for designing, assembling and mechanics experiment. © 2014 SPIE. (8 refs.)Main Heading: Finite element methodControlled terms: Bond (masonry) - Dynamics - Frequency response - Manufacture - Mirrors - Optical testing - Remote sensing - Telescopes - Vibration analysisUncontrolled terms: Dynamic environments - Dynamics analysis - Equivalent stiffness models - Experimental verification - Satellite launches - Space remote sensing - Structural adhesive - Tilt-mirrorClassification Code: 412 Concrete - 537.1 Heat Treatment Processes - 731.1 Control Systems - 741.3 Optical Devices and Systems - 921.6 Numerical Methods - 931.1 Mechanics - 943.2 Mechanical Variables Measurements

Database: Compendex

Plasmonic spectral splitting in multi-resonator-coupled waveguide systems

Zeng, Chao1 Source: Applied Optics, v 53, n 1, p 38-43, January 1, 2014

; ISSN: 1559128X, E-ISSN: 15394522; DOI: 10.1364/AO.53.000038;

Abstract: Spectral splitting is numerically investigated in a metal-insulator-metal plasmonic waveguide coupled with a series of disk cavities for the first time to our best knowledge. The finite-difference time-domain simulations find that, when an identical cavity is introduced into the single-cavity-coupled structure, a resonance peak emerges in reflection dip due to the plasmonic analogue of electromagnetically induced transparency. By cascading multiple cavities into the waveguide system, the resonance spectra are gradually split because of the phase-coupled effects. Particularly, the quality factors of splitting resonance spectra can be rapidly improved with increasing the number of coupled cavities. The proposed plasmonic systems may find potential applications in highly integrated optical circuits, especially for multichannel filtering, all-optical switching, and slow-light devices. © 2014 Optical Society of America. (45 refs.)Main Heading: PlasmonsControlled terms: Metal insulator boundaries - Optical waveguides - Resonance - WaveguidesUncontrolled terms: All-optical switching - Electromagnetically induced transparency - Finite difference time domain simulations - Integrated optical circuit - Metal insulator metals - Multi-channel filtering - Plasmonic waveguides - Slow-light devicesClassification Code: 701 Electricity and Magnetism - 712.1 Semiconducting Materials - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides

Database: Compendex

Secrecy outage and diversity analysis of cognitive radio systems

Zou, Yulong1; Li, Xuelong2; Liang, Ying-Chang3, 4 Source: IEEE Journal on Selected Areas in Communications, v 32, n 11, p 2222-2236, November 1, 2014

; ISSN: 07338716; DOI: 10.1109/JSAC.2014.141121; Article number: 6985747;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Telecommunications and Information Engineering, Nanjing University of Posts and Telecommunications, Nanjing Jiangsu, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an Shaanxi, China3 Institute for Infocomm Research (I2R), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore4 University of Electronic Science and Technology of China (UESTC), Chengdu, China

Abstract: In this paper, we investigate the physical-layer security of a multi-user multi-eavesdropper cognitive radio system, which is composed of multiple cognitive users (CUs) transmitting to a common cognitive base station (CBS), {while multiple eavesdroppers may collaborate with each other or perform independently in intercepting the CUs-CBS transmissions, which are called the coordinated and uncoordinated eavesdroppers, respectively. Considering multiple CUs available, we propose the round-robin scheduling as well as the optimal and suboptimal user scheduling schemes for improving the security of CUs-CBS transmissions against eavesdropping attacks. Specifically, the optimal user scheduling is designed by assuming that the channel state information (CSI) of all links from CUs to CBS, to primary user (PU) and to eavesdroppers are available. By contrast, the suboptimal user scheduling only requires the CSI of CUs-CBS links without the PU's and eavesdroppers' CSI. We derive closed-form expressions of the secrecy outage probability of these three scheduling schemes in the presence of {the coordinated and uncoordinated eavesdroppers. We also carry out the secrecy diversity analysis and show that the round-robin scheduling achieves the diversity order of only one, whereas the optimal and suboptimal scheduling schemes obtain the full secrecy diversity, {no matter whether the eavesdroppers collaborate or not. In addition, numerical secrecy outage results demonstrate that for both the coordinated and uncoordinated eavesdroppers, the optimal user scheduling achieves the best security performance and the round-robin scheduling performs the worst. Finally, upon increasing the number of CUs, the secrecy outage probabilities of the optimal and suboptimal user scheduling schemes both improve significantly. (28 refs.)Main Heading: SchedulingControlled terms: Channel capacity - Channel state information - Cognitive radio - Cognitive systems - Electric circuit breakers - Network layers - Probability - Radio systems - Radio transmission - Routers - Scheduling algorithmsUncontrolled terms: Closed-form expression - Cognitive base stations - Diversity order - Multiuser scheduling - Physical-layer securities - Round-robin scheduling - secrecy diversity - Secrecy outage probabilitiesClassification Code: 706.2 Electric Power Lines and Equipment - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 723 Computer Software, Data Handling and Applications - 723.4 Artificial Intelligence - 912.2 Management - 922.1 Probability Theory

Database: Compendex

Analytical soliton solutions for the cubicquintic nonlinear Schrödinger equation with Raman effect in the nonuniform management systems

Wang, Ping1, 2; Feng, Li1, 3; Shang, Tao1; Guo, Lixin2; Cheng, Guanghua4; Du, Yingjie5 Source: Nonlinear Dynamics, v 79, n 1, p 387-395, 2014

; ISSN: 0924090X; DOI: 10.1007/s11071-014-1672-y;

Publisher: Kluwer Academic PublishersAuthor affiliation: 1 State Key Laboratory of Integrated Service Networks, School of Telecommunications Engineering, Xidian University, Xian, China2 School of Physics and Optoelectronic Engineering, Xidian University, Xian, China3 Zhuhai Comleader Information Science and Technology Co., Ltd, Zhengzhou, China4 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China5 Department of Physics, Northwest University, Xian, China

Abstract: Based on the Kundu–Eckhaus equation with variable coefficients, the exact one-soliton and two-soliton solutions have been explicitly given by an appropriate similarity transformation method. As an example, an exponential distributed fiber control system, nonlinearity management system and dispersion management system have been considered, and the propagation characteristics of the exact soliton solutions in the three nonuniform management systems have been investigated in detail. Especially, the dynamic properties of the amplitude, pulse width and the central position of the soliton with transmission distance have been studied. The results have some guiding significance for soliton amplification, compression and control management, and can provide some theoretical analysis for carrying out optical soliton communication experiment. © 2014, Springer Science+Business Media Dordrecht. (29 refs.)Main Heading: SolitonsControlled terms: Control nonlinearities - Nonlinear equations - Optical communicationUncontrolled terms: Dispersion management - Fiber systems - Guiding significances - Nonlinearity management - Optical soliton communication - Propagation characteristics - Similarity transformation - Transmission distancesClassification Code: 717.1 Optical Communication Systems - 731.1 Control Systems - 921.1 Algebra

Database: Compendex

A radiometric varying robust stereo matching algorithm

Cao, Xiaoqian1, 2; Ma, Caiwen1 Source: Jiqiren/Robot, v 36, n 5, p 634-640, September 1, 2014; Language: Chinese

; ISSN: 10020446; DOI: 10.13973/j.cnki.robot.2014.0634;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanic, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In order to improve the matching rate of radiometric varying stereo images, a novel stereo matching algorithm based on the improved epipolar distance transformation in log-chromaticity space is proposed. In log-chromaticity space, the intensity proportion of stereo image pairs is computed firstly according to raw disparity map; secondly, epipolar distance transformation is performed on left and right images respectively using proportional intensity deviation parameters; at last, the final disparity map is acquired by the belief propagation method. Theoretically, the matching rate of the proposed algorithm is independent of radiometric varying situations including differences in light source's position, spectrum, intensity and the parameters setting of cameras. Experimental results indicate that the matching rate of the proposed algorithm is improved at most 60% comparing with the original epipolar distance transformation algorithm and at most 78% comparing with the state of art algorithms such as ANCC (adaptive normalized cross correlation) when applied to textureless image pairs. (17 refs.)Main Heading: Image matchingControlled terms: Algorithms - Computer vision - Light sources - Radiometry - Stereo image processing - Stereo visionUncontrolled terms: Deviation parameters - Distance transformation - Normalized cross correlation - Parameters setting - Radiometric varying - Stereo image pairs - Stereo matching - Stereo matching algorithmClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 741.2 Vision - 744 Lasers - 921 Mathematics - 944.8 Radiation Measurements

Database: Compendex

An adaptive wavelet transformation used on interference hyperspectral image compression

Wen, Jia1, 2; Ma, Caiwen2; Zhao, Junsuo1; Wang, Cailing3 Source: Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology, v 46, n 7, p 112-117, July 30, 2014; Language: Chinese

; ISSN: 03676234;

Publisher: Harbin Institute of TechnologyAuthor affiliation: 1 Science and Technology on Integrated Information System Laboratory, Institute of Software, Chinese Academy of Sciences, Beijing, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China3 School of Computer Science, Xi'an Shiyou University, Xi'an, China

Abstract: To get better performance of interference hyperspectral image compression, according to the imaging principle ofinterference hyperspectral image, we propose an adaptive direction prediction wavelet transform forLWT (Lifting Wavelet Transformation), to get the best predicted values through adaptive direction in the LWT on the frame direction, and change the order of the traditional wavelet transform. The experiment results prove that the proposed method can get higher SNR at the same bpppb compared with the traditional method, and can get smaller MSE in the recovered spectral curve. (12 refs.)Main Heading: Wavelet transformsControlled terms: Image compression - SpectroscopyUncontrolled terms: Adaptive wavelets - Better performance - Hyper-spectral images - Hyperspectral image compression - Imaging principle - LASIS - Lifting wavelet - Spectrum compressionClassification Code: 741 Light, Optics and Optical Devices - 801 Chemistry - 921.3 Mathematical Transformations

Database: Compendex

System design and research of Yb:YAG thin disk laser with direct cooling arrangement

Song, Qiong-Ge1, 2; Cheng, Guang-Hua1; Bai, Jing1; Liu, Xin1; Tang, Wen-Long1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 10, October 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144310.1014001; Article number: 1014001;

Abstract: A Yb:YAG thin disk laser with a novel four-pass pumped structure and direct water cooling device was designed. The multi-mode pump radiation was from a fiber-coupled 940 nm diode laser. The Yb:YAG disk with 10 mm diameter and 500 μm thickness was employed. The Yb3+ atom fraction was 10%. The direct cooling arrangement was put forward, tap water was contacted with the Yb:YAG through a V groove. The four-pass pump coupling system was well designed with a pair of rectangular prism and a focusing lens which had a diameter of 50 mm and focus of 50 mm. Then simulated the stability of the resonator and calculated the radius of the laser spot in different position of the resonator with the different cavity length. Different types of laser cavity were set up. With the output coupling rate of 5%, the maximum output power of 3.28 W at 1 031 nm was obtained in F-P resonator. The beam quality M<inf>x</inf>2=1.79, M<inf>y</inf>2=1.86. The slope efficiency was 20.5%. (16 refs.)Main Heading: Pumping (laser)Controlled terms: Cooling - Cooling water - Crystal structure - Lasers - Resonators - Solid state lasers - YtterbiumUncontrolled terms: Direct water cooling - Laser crystals - Pump structure - Thin-disk lasers - YAGClassification Code: 547.2 Rare Earth Metals - 616 Heat Exchangers - 641.2 Heat Transfer - 714 Electronic Components and Tubes - 714.2 Semiconductor Devices and Integrated Circuits - 744.1 Lasers, General - 744.4 Solid State Lasers - 801.4 Physical Chemistry

Database: Compendex

Improved adaptive control for wing rock via fuzzy neural network with randomly assigned fuzzy membership function parameters

Rong, Hai-Jun1; Han, Sai2; Bai, Jian-Ming3; Liang, Yong-Qi1 Source: Aerospace Science and Technology, v 39, p 614-627, December 2014

; ISSN: 12709638; DOI: 10.1016/j.ast.2014.06.009;

Publisher: Elsevier Masson SASAuthor affiliation: 1 State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi'an Jiaotong University, Xi'an, ShaanXi, China2 Institute of Avionics and Flight Control, AVIC Xi'an Aircraft Branch Company, Yanliang, ShaanXi, China3 Optical Direction and Pointing Technique Research Department, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, ShaanXi, China

Abstract: Two stable adaptive fuzzy-neural control schemes within the indirect and direct frameworks are proposed to suppress the wing rock occurring at high angles of attack. In the two control strategies, a fuzzy neural network (FNN) with any bounded nonconstant piecewise continuous membership function is used to approximate the system nonlinear dynamics and external disturbances. Differently from the existing techniques, the parameters of the fuzzy membership functions are determined based on the recently developed fuzzy-neural algorithm named online sequential fuzzy extreme learning machine (OS-Fuzzy-ELM) where the fuzzy membership function parameters need not be adjusted and could randomly be generated according to any given continuous probability distribution without any prior knowledge. This simplifies the design of the controllers. Furthermore to ensure stable control performance, the tuning laws of the consequent parameters are derived using the projection algorithm and Lyapunov stability theorem. The merits of the proposed control schemes lie in the simplicity, robustness and stability, which manifests they can be applied for online learning and real-time control. In order to evaluate the performance of the proposed two control schemes, a comparison between a neural control, a fuzzy control and a fuzzy-neural control is carried out on various initial conditions. Results indicate the performance of the proposed controllers is superior using the randomly assigned fuzzy membership function parameters. (34 refs.)Main Heading: Membership functionsControlled terms: Adaptive control systems - Angle of attack - Controllers - Fuzzy control - Fuzzy neural networks - Knowledge acquisition - Learning systems - Parameter estimation - Probability distributions - Real time control - Social networking (online)Uncontrolled terms: Adaptive Control - Continuous probability distribution - External disturbances - Extreme learning machine - Fuzzy membership function - Fuzzy-Neural algorithms - Lyapunov stability theorem - Wing rocksClassification Code: 651.1 Aerodynamics, General - 723 Computer Software, Data Handling and Applications - 723.4 Artificial Intelligence - 731 Automatic Control Principles and Applications - 731.1 Control Systems - 732 Control Devices - 732.1 Control Equipment - 921 Mathematics - 922.1 Probability Theory

Database: Compendex

Learning from errors in super-resolution

Tang, Yi1; Yuan, Yuan2 Source: IEEE Transactions on Cybernetics, v 44, n 11, p 2143-2154, November 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2014.2301732; Article number: 6870435;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Mathematics and Computer Science, Yunnan University of Nationalities, Kunming, China2 Center for Optical Imagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an, China

Abstract: A novel framework of learning-based super-resolution is proposed by employing the process of learning from the estimation errors. The estimation errors generated by different learning-based super-resolution algorithms are statistically shown to be sparse and uncertain. The sparsity of the estimation errors means most of estimation errors are small enough. The uncertainty of the estimation errors means the location of the pixel with larger estimation error is random. Noticing the prior information about the estimation errors, a nonlinear boosting process of learning from these estimation errors is introduced into the general framework of the learning-based super-resolution. Within the novel framework of super-resolution, a low-rank decomposition technique is used to share the information of different super-resolution estimations and to remove the sparse estimation errors from different learning algorithms or training samples. The experimental results show the effectiveness and the efficiency of the proposed framework in enhancing the performance of different learning-based algorithms. © 2013 IEEE. (42 refs.)Main Heading: Learning algorithmsControlled terms: Estimation - Optical resolving power - Random errorsUncontrolled terms: Boosting - Learning from errors - Learning-based algorithms - Learning-based super-resolution - Low-rank decomposition - Process of learning - Sparse estimation - sparsityClassification Code: 723 Computer Software, Data Handling and Applications - 741.1 Light/Optics - 921 Mathematics - 922 Statistical Methods

Database: Compendex

Space target sequence image simulation based on STK/matlab

Liu, Fucheng1, 2; Liu, Zhaohui1; Liu, Wen1; Liang, Dongsheng1, 2; Yuan, Hui1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 9, p 3157-3161, September 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: A method for sequence image generation of dim point moving targets in complex star background was presented based on STK/matlab software. Firstly, the starry background modeling process was analyzed; then, the satellite disturbance and noise that affected the point target imaging were detailedly discussed to make sequence images simulated closer to the real world; and besides the space target was modeled and its relative geometric relationship with the observation satellite was predicted by the STK software, at the same time the visibility of high earth orbit was systematically analyzed. In addition, a simple and convenient method to calculate the space target visibility criterion was given. By taking into account of various factors that impacted the visibility of high earth orbit target, the space target orbit prediction data was generated by STK and then matlab software was adopted to simulate the sequence image. It's useful in providing space environment for detection and tracking space target. (10 refs.)Main Heading: Earth (planet)Controlled terms: MATLAB - Monte Carlo methods - Orbits - Stars - Target tracking - VisibilityUncontrolled terms: Detection and tracking - Geometric relationships - High earth orbits - Observation satellites - Sequence images - Space targets - Visibility analysis - Visibility criterionClassification Code: 655.2 Satellites - 657 Space Physics - 657.2 Extraterrestrial Physics and Stellar Phenomena - 716.2 Radar Systems and Equipment - 741.2 Vision - 921 Mathematics - 922.2 Mathematical Statistics

Database: Compendex

Plasmon-induced transparency in metal-insulator-metal waveguide side-coupled with multiple cavities

Guo, Jing1 Source: Applied Optics, n 8, p 1604-1609, March 10, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.001604;

Abstract: We have demonstrated the analogue of electromagnetically induced transparency (EIT) in the metal-insulator-metal plasmonic waveguide, which consists of a bus waveguide side-coupled with a series of slot cavities. By finite-difference time-domain simulations, it is found that the resonance wavelength of the slot cavity can be controlled by adjusting the length of the cavity. Moreover, the EIT-like response is strongly dependent on the coupling separation between the corresponding adjacent cavities. Multiple-peak plasmon-induced transparency can be realized by cascading multiple cavities with different lengths and suitable cavity-cavity separations. This ultracompact plasmonic waveguide system may find important applications for multichannel plasmonic filter, nanoscale optical switching, and slow-light devices in highly integrated optical circuits and networks. © 2014 Optical Society of America. (61 refs.)Main Heading: Waveguide filtersControlled terms: Finite difference time domain method - Metal insulator boundaries - Metals - MIM devices - Networks (circuits) - Optical waveguides - Photonic integration technology - Plasmons - Quantum optics - Semiconductor insulator boundaries - Slow light - Time domain analysis - Transparency - WaveguidesUncontrolled terms: Electromagnetically-induced transparency - Finite difference time domain simulations - Induced transparency - Integrated optical circuit - Metal insulator metals - Metal-insulator-metal waveguides - Plasmonic waveguides - Resonance wavelengthsClassification Code: 531 Metallurgy and Metallography - 703.1 Electric Networks - 712.1 Semiconducting Materials - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 741.1 Light/Optics - 921 Mathematics

Database: Compendex

Toward scalable systems for big data analytics: A technology tutorial

Hu, Han1, 2; Wen, Yonggang1, 3; Chua, Tat-Seng1, 2; Li, Xuelong1, 4 Source: IEEE Access, v 2, p 652-687, 2014; E-ISSN: 21693536; DOI: 10.1109/ACCESS.2014.2332453; Article number: 6842585;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 IEEE, United States2 School of Computing, National University of Singapore, Singapore, Singapore3 School of Computer Engineering, Nanyang Technological University, Singapore, Singapore4 State Key Laboratory of Transient Optics and Photonics, Center for Optical Imagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Xi'an, China

Abstract: Recent technological advancements have led to a deluge of data from distinctive domains (e.g., health care and scientific sensors, user-generated data, Internet and financial companies, and supply chain systems) over the past two decades. The term big data was coined to capture the meaning of this emerging trend. In addition to its sheer volume, big data also exhibits other unique characteristics as compared with traditional data. For instance, big data is commonly unstructured and require more real-time analysis. This development calls for new system architectures for data acquisition, transmission, storage, and large-scale data processing mechanisms. In this paper, we present a literature survey and system tutorial for big data analytics platforms, aiming to provide an overall picture for nonexpert readers and instill a do-it-yourself spirit for advanced audiences to customize their own big-data solutions. First, we present the definition of big data and discuss big data challenges. Next, we present a systematic framework to decompose big data systems into four sequential modules, namely data generation, data acquisition, data storage, and data analytics. These four modules form a big data value chain. Following that, we present a detailed survey of numerous approaches and mechanisms from research and industry communities. In addition, we present the prevalent Hadoop framework for addressing big data challenges. Finally, we outline several evaluation benchmarks and potential research directions for big data systems. © 2014 IEEE. (290 refs.)Main Heading: Big dataControlled terms: Chains - Cloud computing - Data acquisition - Data handling - Digital storage - Distributed computer systems - Industrial research - Supply chains - SurveysUncontrolled terms: Data analytics - Data storage - Hadoop - Large-scale data processing - Potential researches - System architectures - Systematic framework - Technological advancementClassification Code: 405.3 Surveying - 602.1 Mechanical Drives - 722.1 Data Storage, Equipment and Techniques - 722.4 Digital Computers and Systems - 723.2 Data Processing and Image Processing - 912 Industrial Engineering and Management - 912.1 Industrial Engineering - 913 Production Planning and Control; Manufacturing

Database: Compendex

Investigations of switchable fiber soliton laser mode-locked by carbon nanotubes

Han, Dongdong1; Zeng, Chao1 Source: Optics Communications, v 319, p 25-30, May 15, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.01.002;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We have numerically and experimentally investigated a switchable erbium-doped fiber (EDF) laser mode-locked by single-walled carbon nanotubes for the first time to our best knowledge. Depending on the pump power, the central wavelength of the mode-locked pulse can be switched from about 1531 to 1557 nm. The formation and evolution of the switchable soliton operation are investigated numerically by solving the extended nonlinear Schrödinger equation with the appropriate gain profile. Numerical results demonstrate that the switchable mode-locking operation is attributed to the variation of the gain spectrum of EDF, agreeing well with the experimental observations. (72 refs.)Main Heading: Mode-locked fiber lasersControlled terms: Carbon - Fiber lasers - Laser mode locking - Laser modes - Locks (fasteners) - Nanotubes - Nonlinear equations - Optical pumping - Single-walled carbon nanotubes (SWCN) - Solitons - YarnUncontrolled terms: Central wavelength - Dinger equation - Erbium doped fiber laser - Formation and evolutions - Mode-locked pulse - Numerical results - Soliton laser - SwitchableClassification Code: 601.3 Mechanisms - 741.1 Light/Optics - 741.1.2 Fiber Optics - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 819.4 Fiber Products - 921.1 Algebra

Database: Compendex

High-contrast electro-optic modulation of spatial light induced by graphene-integrated Fabry-Pérot microcavity

Zeng, Chao1; Guo, Jing1; Liu, Xueming1 Source: Applied Physics Letters, v 105, n 12, September 22, 2014

; ISSN: 00036951; DOI: 10.1063/1.4895633; Article number: 121103;

Abstract: We have proposed a graphene-integrated Fabry-Pérot microcavity for efficient modulation of spatial light. A simplified theoretical model is established to analyze the performance of our system, and the calculated results agree well with the simulation results. It is shown that the plasmon-induced transparency (PIT) effect is achieved in the proposed microcavity and the central frequency of PIT window can be dynamically tuned by gate voltages. In particular, the PIT spectra exhibit extremely large modulation depths (&sim; 90%) across a broad range of frequencies. The proposed ultracompact configuration demonstrates a type of cavity-induced high-contrast and frequency-selective electro-optic modulators, offering opportunities in exploiting active chip-integrated high-performance devices operating at frequencies from terahertz to mid-infrared. © 2014 AIP Publishing LLC. (26 refs.)Main Heading: MicrocavitiesControlled terms: Computer simulation - Graphene - Modulation - ModulatorsUncontrolled terms: Central frequency - Electro-optic modulation - Electro-optic modulators - Frequency-selective - High performance devices - Induced transparency - Large modulation depth - Theoretical modelingClassification Code: 713.3 Modulators, Demodulators, Limiters, Discriminators, Mixers - 714 Electronic Components and Tubes - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 723.5 Computer Applications - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Distributed object detection with linear SVMs

Pang, Yanwei1; Zhang, Kun1; Yuan, Yuan2; Wang, Kongqiao3 Source: IEEE Transactions on Cybernetics, v 44, n 11, p 2122-2133, November 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2014.2301453; Article number: 6748917;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic Information Engineering, Tianjin University, Tianjin, China2 Center for Optical Imagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an, China3 Nokia Research Center, Beijing, China

Abstract: In vision and learning, low computational complexity and high generalization are two important goals for video object detection. Low computational complexity here means not only fast speed but also less energy consumption. The sliding window object detection method with linear support vector machines (SVMs) is a general object detection framework. The computational cost is herein mainly paid in complex feature extraction and innerproduct-based classification. This paper first develops a distributed object detection framework (DOD) by making the best use of spatial-temporal correlation, where the process of feature extraction and classification is distributed in the current frame and several previous frames. In each framework, only subfeature vectors are extracted and the response of partial linear classifier (i.e., subdecision value) is computed. To reduce the dimension of traditional block-based histograms of oriented gradients (BHOG) feature vector, this paper proposes a cell-based HOG (CHOG) algorithm, where the features in one cell are not shared with overlapping blocks. Using CHOG as feature descriptor, we develop CHOG-DOD as an instance of DOD framework. Experimental results on detection of hand, face, and pedestrian in video show the superiority of the proposed method. © 2014 IEEE. (58 refs.)Main Heading: Feature extractionControlled terms: Artificial intelligence - Classification (of information) - Computational complexity - Computer vision - Energy utilization - Extraction - Face recognition - Graphic methods - Learning systems - Object recognition - Support vector machinesUncontrolled terms: Feature extraction and classification - Histograms of oriented gradients - Linear classifiers - Linear Support Vector Machines - Low computational complexity - Object Detection - Spatial-temporal correlation - Video object detectionsClassification Code: 525.3 Energy Utilization - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 723 Computer Software, Data Handling and Applications - 802.3 Chemical Operations

Database: Compendex

Tracking of infrared small-target based on improved Mean-Shift algorithm

Yang, Yifan1, 2; Tian, Yan1; Yang, Fan2, 3; Huang, Biao1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 7, p 2164-2169, July 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 National Time Service Center, Chinese Academy of Sciences, Xi'an, China

Abstract: Small-target tracking in infrared imagery with a complex background is always an important task in object tracking fields. Small and manoeuvrable objects in complex clutter and highly noised background usually results in serious false alarm in target tarking for low contrast of infrared imagery. An improved Mean-Shift algorithm to handle the influnce of complex background during tracking the smalltarget in infrared imagery was proposed. This work proposed an adaptive nonlinear machine to help Mean-Shift algorithm to get stable histogram of the interesting areas. This machine expanded the imformation of object histogram refer to the mean value of tracking window, as well as reduced the noise part of tracking window refer to the standard deviation of it. At the same time, algorithm fused the histograms of gradient with histogram of gray-value to discribe the target. To validate the effection of the proposed algorithm, the last part conduct a series tracking experiments which choose highly noised and clutered videos as their candidates. The comparison of the tracking results between tradtional Mean-Shift algotithm and improved Mean-Shift algorithm shows that the proposed algorithm has a more accurate tracking effection. Further more the proposed algorithm highly reduced the wobbleing between small-target and tracking window. This indicates that the improved algorithm achieved more robustness. (10 refs.)Main Heading: Target trackingControlled terms: Algorithms - Clutter (information theory) - Color image processing - Fusion reactions - Graphic methods - Statistical methodsUncontrolled terms: Accurate tracking - Adaptive - Complex background - Mean shift - Mean shift algorithm - Nonlinear - Small-Target Tracking - Standard deviationClassification Code: 621.2 Fusion Reactors - 716.1 Information Theory and Signal Processing - 716.2 Radar Systems and Equipment - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741.1 Light/Optics - 921 Mathematics - 922.2 Mathematical Statistics

Database: Compendex

Correct non-uniformity of scientific grade CCD in measuring laser near field distributing

Lin, Hui1; Liu, Lili1; Tian, Xinfeng1; Hao, Yun2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 7, p 2108-2111, July 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 China Shaanxi Lingyun Technology Company, Ltd, Xi'an , China

Abstract: The reason of photo response non-uniformity (PRNU) of image sensor's photo response was analyzed in this paper at first. It was concluded in two faces, one caused by spatial noise which based on materials, manufacture crafts and offset and another caused by temporal noise which based on its response with time drift, theses two factors influence the PRNU of image sensor's photo response gravely. To describe the affection of spatial noise and temporal noise, the model of sensor based on the hypothesis that linear of image sensor's photo response was made, and the erase non-uniformity of CCD by Least Square Methods based on this model was proposed. Experiment results show that the proposed algorithm is effective to the correction of image sensor's PRNU. (8 refs.)Main Heading: Least squares approximationsControlled terms: Charge coupled devices - Image sensorsUncontrolled terms: Least square methods - Near fields - Nonuniformity - Photo response non-uniformity - Photoresponses - Scientific grade CCD - Spatial noise - Temporal noiseClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

A secondary mirror adjustment system with hexapod structure for optical telescope application

Zhou, Nan1, 2; Li, Chuang1; Gao, Wei1; Song, Zong Xi1; Zhao, Chao1, 2; Ren, Guo Rui1, 2; Jing, Nan1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2068311; Article number: 92800N; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Benefiting from low cost, light weight and reduced volume in launch, deployable optical telescopes will be extensively applied in microsatellites. As a result of manufactured tolerance and external disturbance, the secondary mirror can't arrive at designed position precisely after a deployable telescope is unfolded. We investigate an adjustment system with six degrees of freedom based on hexapod structure to solve this problem. There are mainly four parts in this paper. Firstly, the adjustment methods of deployable telescopes for microsatellites are introduced. Generally several kinds of optical components can be adjusted to align a deployed telescope: primary mirror, tip/tilt mirror and secondary mirror. Due to its high sensitivity and convenience, the secondary mirror is chosen to collimate the optical system of the telescope. Secondly, an adjustment system with hexapod structure is designed for a secondary mirror with 85 mm diameter. After comparing the characteristics of step motors, piezo actuators and voice coil motors (VCMs), VCMs are selected as the linear actuators. By using optical gratings as displacement sensors in the system, we can make closed-loop control come true. The hexapod structure mainly consists of 6 VCMs, 6 optical gratings and 6 oblique legs with flexible hinges. The secondary mirror adjustment system is 83 mm in diameter and 55 mm high. It has tip/tilt rotational ranges of ±2.205° with resolution of better than ±0.007°, and translational ranges of ±1.545 mm with resolution of better than ±0.966 μm. Thirdly, the maximum stress and the maximum deformation in the adjustment system are computed with finite element method. At last, the kinematics problems of the adjustment system are discussed. © 2014 SPIE. (11 refs.)Main Heading: Optical testingControlled terms: Actuators - Degrees of freedom (mechanics) - DNA sequences - Electric machine theory - Finite element method - Linear actuators - Manufacture - Mirrors - Optical systems - Optical telescopes - Position control - Stepping motorsUncontrolled terms: Deployable optical telescopes - External disturbances - Flexible hinges - Hexapod - Secondary mirror - Six degrees of freedom - Telescope applications - Voice coil motorsClassification Code: 461.2 Biological Materials and Tissue Engineering - 537.1 Heat Treatment Processes - 705.1 Electric Machinery, General - 705.3 Electric Motors - 731.3 Specific Variables Control - 731.5 Robotics - 732.1 Control Equipment - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

Design of a high aperture compression ratio, dual-band static Fourier transform imaging spectrometer for remote sensing

Zou, Chun-Bo1, 2; Hu, Bing-Liang2; Li, Li-Bo1, 2; Bai, Qing-Lan2; Sun, Xin2; Li, Ran2; Yang, Jian-Feng2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9298, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413847; DOI: 10.1117/12.2083243; Article number: 929811; Conference: International Symposium on Optoelectronic Technology and Application 2014: Imaging Spectroscopy; and Telescopes and Large Optics, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 XI'AN Institute of Optics and Precision Mechanics Chinese Academy of Sciences, China2 China University Academy of Sciences, China

Abstract: A novel dual-band static Fourier transform imaging spectrometer was designed, which was the spatioorally modulated imaging Fourier transform spectrometer based on Sagnac interferometer. The approach represented a simplification and mass reduction over the traditional approach. It could obtain two-dimensional spatial images and one dimensional spectral image in two bands simultaneously. The two bands was separated through a dichroic prism and imaging in two detectors. one band was the visible and near infrared band, with the spectral range 400nm-1000nm and spectral resolution 187.5 wave numbers; the other was the short wave infrared band, with the spectral range 1000nm- 2500nm and spectral resolution 150 wave numbers. To reduce the size of the Interferometer, a high aperture compression ratio telescope system was designed before. The optical aperture was compressed to 1/10, and the volume of interferometer was reduced to 1/1000. For the convenience of engineering implementation, the telescope was composed of two no-aberration object lens: fore-lens and Collimating lens. The two band imaging spectrometers shared the primary lens and the second lens of the fore-lens and use their own collimating lens, interferometers and Fourier transform lens. The collimating lens and the Fourier transform lens of each spectrometer could be designed to the same structural style and parameters. The both spectrometers had a focal length of 1000mm, F number of 5, FOV(field of view) of 1°. Moreover, both image qualities were close to the diffraction limit, the distortion was less than 2%. The advantage of the instrument was that dual band spectral image could be acquired at the same time and the interferometer was miniaturized extremely in the case of unchanged technical indicators. © 2014 SPIE. (11 refs.)Main Heading: SpectrometersControlled terms: Diffraction - Fourier transform infrared spectroscopy - Fourier transforms - Infrared devices - Infrared radiation - Interferometers - Optical systems - Remote sensing - Spectral resolution - Spectroscopy - TelescopesUncontrolled terms: Dual Band - Engineering implementation - Fourier spectrometer - Fourier transform imaging spectrometers - Fourier transform lens - Short wave infrared bands - Traditional approaches - Visible and near infraredClassification Code: 731.1 Control Systems - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 801 Chemistry - 921.3 Mathematical Transformations - 941.3 Optical Instruments

Database: Compendex

Plasmonic sensor based on perfect absorber with metallic nanoring structures

Lu, Xiaoyuan1; Zhang, Wenfu1; Zhang, Lingxuan1; Wan, Rengang1; Zhang, Tongyi1; Wangy, Guoxi1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9275, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413489; DOI: 10.1117/12.2086963; Article number: 92751S; Conference: Infrared, Millimeter-Wave, and Terahertz Technologies III, October 9, 2014 - October 10, 2014; Sponsor: Chinese Optical Society (COS); The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We propose a nanoring array structure backed by a metal mirror to achieve perfect infrared absorber with absorption as high as 99:99%. The frequency of the absorption peak strongly depends on the refractive index surrounding the structured surface. This novel feature can be used as plasmonic sensor for refractive index measurement. This plasmonic sensor possesses sensitivity of 600 nm/RIU and the gure of merit can be 180. Due to the high sensitivity and simple sensing scheme, the sensing strategy can nd potential applications in nonlaboratory environments. © 2014 SPIE. (38 refs.)Main Heading: Refractive indexControlled terms: Infrared detectors - Millimeter waves - Nanorings - Nanostructured materials - Plasmons - Terahertz wavesUncontrolled terms: High sensitivity - Infra-red sensor - Nano-ring structures - Perfect absorber - Plasmonic sensors - Plasmonics - Refractive index measurement - Structured surfacesClassification Code: 711 Electromagnetic Waves - 712.1 Semiconducting Materials - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 761 Nanotechnology - 933 Solid State Physics

Database: Compendex

Reflective carbon nanotube as the saturable absorber for mode-locked 1064nm laser

Fan, Mingwen1; Ma, Baomin2; Liu, Jie1; Wang, Yonggang3 Source: Optik, October 22, 2013

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.07.051 Article in PressAuthor affiliation: 1 College of Physics and Electronics, Shandong Normal University, Jinan 250014, China2 School of Information Science and Engineering, Shandong University, Jinan 250100, China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: With a reflective single-walled carbon nanotube as the saturable absorber, a laser diode-pumped passively mode-locked Nd:YVO<inf>4</inf> laser at 1064nm was realized for the first time. The pulse duration of 12ps was produced with a repetition rate of 83.7MHz. The peak power and the single pulse energy of the mode-locking laser were 1.28kW and 15.4nJ, respectively. © 2014 Elsevier GmbH.Main Heading: Mode-locked fiber lasersControlled terms: Locks (fasteners) - Passive mode locking - Pumping (laser) - Q switched lasers - Saturable absorbers - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Laser-diode-pumped - Mode-locked - Modelocking - Passively mode-locked - Peak power - Pulse durations - Repetition rate - Single pulse energyClassification Code: 601.3 Mechanisms - 744.1 Lasers, General - 761 Nanotechnology

Database: Compendex

Tunable and switchable multi-wavelength dissipative soliton generation in a graphene oxide mode-locked Yb-doped fiber laser

Huang, Shisheng1; Wang, Yonggang2; Yan, Peiguang1; Zhao, Junqing1; Li, Huiquan1; Lin, Rongyong1 Source: Optics Express, v 22, n 10, p 11417-11426, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.011417;

Publisher: Optical Society of AmericaAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, Shenzhen University, ShenZhen, 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China

Abstract: We report the generation of tunable single-, switchable and tunable dual-, and stable triple-wavelength dissipative solitons (DSs) in an all-normal-dispersion mode-locked Yb-doped fiber laser based on a graphene-oxide saturable absorber (GOSA) without additional components (such as optical filter, or fiber grating). The tunable single-wavelength DS have a wide wavelength-tunable range of 16.4 nm. The dual-wavelength DSs not only have a wavelength-tunable range (about 10 nm) but also have variable wavelength spacing (3.8-13.8 nm). The formation dynamics of the triple-wavelength DSs was also investigated experimentally. The different operations of tunable single-, switchable and tunable dual-, and stable triple-wavelength DSs depend on the strength of the cavity birefringence. The simple, compact all-fiber DS laser with lasing wavelength tunability and flexibility can meet great potential for applications. © 2014 Optical Society of America. (28 refs.)Main Heading: WavelengthControlled terms: Fiber lasers - Graphene - Locks (fasteners) - Mode-locked fiber lasers - Saturable absorbers - Solitons - YtterbiumUncontrolled terms: All normal dispersions - Dissipative solitons - Formation dynamics - Switchable multi wavelengths - Triple wavelengths - Wavelength spacing - Wavelength tunable - Yb-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 711 Electromagnetic Waves - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally - 931.3 Atomic and Molecular Physics

Database: Compendex

Transport properties of random media composed of core-shell spheres

Xu, Yuchen1; Zhang, Hao1, 2; Zhang, Xiangchao1; Shen, Yongqiang1; Zhu, Heyuan1; Lei, Ming2; Xu, Min1 Source: Applied Physics A: Materials Science and Processing, v 114, n 4, p 1223-1231, March 2014

; ISSN: 09478396, E-ISSN: 14320630; DOI: 10.1007/s00339-013-7862-5;

Publisher: Springer HeidelbergAuthor affiliation: 1 Shanghai Engineering Center for Ultra-precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China2 State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: With the energy-density coherent potential approximation method, a series of calculations concerning the contribution from the morphology and dispersion of random media composed of core-shell spheres on the transport properties of random media are conducted in terms of the scattering-cross-section efficiency factor, mean free path, velocity of electromagnetic energy, and diffusion coefficient. It is found that the core layer introduces more complicated resonant modes which lead to diverse possibilities to sharply decrease the transport of light within random media. © 2013 Springer-Verlag Berlin Heidelberg. (21 refs.)Main Heading: Random processesControlled terms: Coherent scattering - Diffusion - Electromagnetic waves - Transport propertiesUncontrolled terms: Coherent potential approximation - Core layers - Core-shell spheres - Efficiency factor - Energy density - Mean free path - Random media - Resonant modeClassification Code: 711 Electromagnetic Waves - 922.1 Probability Theory - 931.1 Mechanics - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

Achromatic snapshot imaging polarimeter using modified Savart polariscopes and hybrid (refractive-diffractive) lenses

Cao, Qizhi1, 2, 3; Zhang, Chunmin1; Zhang, Jing3; Kang, Yongqiang1, 2 Source: Optik, v 125, n 13, p 3380-3383, July 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.12.069;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Institute of Space Optics, Ministry of Education, Xi'An Jiaotong University, Xi'an 710049, China2 Spatial Optics Department, Xi'An Institute of Optics and Precision Mechanics, Academia Sinica, Xi'an 710048, China3 School of Physics and Electronic Information Science, Guangxi Teacher Education University, Nanning 530023, China

Abstract: This paper presents the layout of achromatic snapshot imaging polarimeter (SIP) using modified Savart plates (MSPs) and working under nature light. The hybrid (refractive-diffractive) lenses are used to achieve the achromatic point-spread function (PSF), and the design probe the four Stokes vectors of the object by using polarization analyzing optics comprising two MSPs, a half wave plate, and an analyzer. In comparison with the monochromatic or quasi-monochromatic SIP using MSPs reported previously, the most remarkable property of the proposed layouts is to have the capability of directly detecting the object with natural illumination. Also, the configuration is more easily manipulated and robust than achromatic conventional Savart polariscopes reported previously in probing the object with axial movement. The feasibility is verified by numerical simulation for natural light. © 2014 Elsevier GmbH. (17 refs.)Main Heading: PolarimetersControlled terms: Light - Ray tracingUncontrolled terms: Achromatic - Axial movement - Hybrid lens - Imaging Polarimeter - Natural illumination - Point-spread functions - Quasi-monochromatic - Savart polariscopeClassification Code: 741.1 Light/Optics - 941.3 Optical Instruments

Database: Compendex

Design of vibration-insensitive Sagnac fiber-optic current sensors using spun high-birefringence fibers

Kang, Meng-Hua1, 2; Wang, Ying-Li1; Ren, Li-Yong1; Xu, Jin-Tao1, 3; Liang, Jian1; Qu, En-Shi1 Source: Journal of Modern Optics, v 61, n 14, p 1120-1126, August 16, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.922630;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China2 University of Chinese Academy of Sciences, Beijing, China3 Xian Sino Huaxin Measurement and Control Co., Ltd, Xian, China

Abstract: A novel fiber-optic current sensing element is proposed to enhance sensor performance using spun high-birefringence fibers. Such element includes three fiber sections. Two terminal sections with a varying spin rate along the fiber are utilized to replace the fiber quarter-wave plates, each converting the light polarization state from linear to circular and vice versa. The middle section with a uniform spin rate is utilized as the current sensing fiber that maintains the circular polarization state during the light propagation. The fiber is also wound into a special geometric structure so that the Sagnac phase shift can be inherently eliminated, and the sensing result does not depend on the position of the current conductor. The evolution of the light polarization state was analyzed using coupled-mode theory with different polarization state incidents in the sensing fiber. A sensor scheme based on this type of spun fiber is also proposed. © 2014 Taylor & Francis. (18 refs.)Main Heading: Spinning (fibers)Controlled terms: Birefringence - Fiber optic sensors - Fibers - Light polarization - SensorsUncontrolled terms: Circular polarization state - Coupled-mode theory - Current conductors - Fiber-optic current sensor - Geometric structure - High-birefringence fibers - Spun fiber - Vibration insensitivityClassification Code: 741.1 Light/Optics - 741.1.2 Fiber Optics - 801 Chemistry - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications - 819.3 Fiber Chemistry and Processing

Database: Compendex

The design of freeform surface Fresnel lens used for LED uniform illumination

Dai, Yi Dan1, 2; Qu, En Shi1; Ren, Li Yong1; Du, Xin Chao1, 2; Ju, Hai Juan1 Source: Applied Mechanics and Materials, v 571-572, p 976-979, 2014, Computers and Information Processing Technologies I

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351399; DOI: 10.4028/www.scientific.net/AMM.571-572.976;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: This paper presents a new kind of light emitting diode(LED) secondary light distribution lens which adopts the type of Fresnel lens surface. The research purpose of this paper is to improve the LED heat dissipation efficiency of the secondary light distribution lens and the light efficiency, so as to prolong the service life of the LED. In this paper, we use the numerical method for solving the partial differential equation to establish a freeform surface lens which could produce uniform illumination, then the innovative method of combine the Fresnel lens structure with freeform surface lens was proposed. The design of freeform surface Fresnel lens allows dramatically cut the thickness of the lens (as well as the weight and volume), it can solve the problem of difficulty in heat dissipation. By comparing the ray tracing simulation results of original freeform surface lens and freeform surface Fresnel lens in optical simulation software, experiments show that the latter not only shows the same degree of illumination uniformity, but also greatly reduced the thickness of the lens. © (2014) Trans Tech Publications, Switzerland. (12 refs.)Main Heading: Light emitting diodesControlled terms: Computer software - Data processing - Inertial confinement fusion - Optical instrument lenses - Surfaces - Thermal diffusivityUncontrolled terms: Free-form surface - Fresnel lens - Illumination uniformity - Innovative method - Light distribution - Optical simulation - Ray tracing simulation - Uniform illuminationClassification Code: 616 Heat Exchangers - 621.2 Fusion Reactors - 641 Heat and Mass Transfer; Thermodynamics - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 931 Classical Physics; Quantum Theory; Relativity - 951 Materials Science

Database: Compendex

The precision analysis of continuous zoom lens in airborne electro-optical pod

Yang, Xiao-Xu1; Li, Da-Wei1; Han, Jun-Feng1; Dong, Qiang1, 2; Huang, Wei1; Wei, Yu1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9142, 2014, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410938; DOI: 10.1117/12.2054095; Article number: 91421I; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013, October 20, 2013 - October 29, 2013; Sponsor: Chinese Society of Astronautics; ducation, Shanghai Jiaotong University; Education and Training Department, China; Key Laboratory for Laser Plasmas, Ministry of E; Ordnance Society; Photoelectronic Technology Professional Committee,;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, 710119, China2 University of Chinese Academy of Science, Beijing, 100039, China

Abstract: In the research of electro-optical pod, this paper propose a mission requirements that continuous zoom lens system is using for measuring angle in the process. This paper analyzes the influence of angle measurement accuracy from focal length and optical axis errors in the process of continuous zoom, and given the mathematical model of the influence of angle measurement accuracy. The simulation analysis indicated that Angle measuring accuracy is affected by the process of continuous zoom. The simulation analysis results have certain instructive significance to engineering practice. © 2014 Copyright SPIE. (6 refs.)Main Heading: Angle measurementControlled terms: Mathematical models - Optical engineering - Optical image storage - Remote sensingUncontrolled terms: Angle measuring - Continuous zooms - Electro-optical - Engineering practices - Measurement accuracy - Mission requirements - Precision analysis - Simulation analysisClassification Code: 731.1 Control Systems - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921 Mathematics - 943.2 Mechanical Variables Measurements

Database: Compendex

Dielectric barrier plasma dynamics for active aerodynamic flow control

Hao, Jiang Nan1, 3; Tian, Ba Lin2; Wang, Yu Lin1; Song, Ya Hui1; Pan, Shu Cheng1; Li, Wen Feng1 Source: Science China: Physics, Mechanics and Astronomy, v 57, n 2, p 345-353, February 2014

; ISSN: 16747348; DOI: 10.1007/s11433-013-5164-8;

Publisher: Science in China PressAuthor affiliation: 1 National Key Laboratory of Aerodynamic Design and Research, Northwestern Polytechnical University, Xi'an 710072, China2 Xi'an Communications Institute, Xi'an 710106, China3 Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy Sciences, Xi'an 710061, China

Abstract: The paper investigates the dynamics of a new multiple bipolar multiple Dielectric Barrier Discharges (DBD) actuator using in large-scale flow control. Particle image velocimetry experiments are performed to characteristic the effectiveness of the multiple bipolar DBD plasma actuator. The results show that the mutual interaction between the electrodes, one major disadvantage of traditional DBD characterized by reverse discharge can be entirely avoided, and a constantly accelerating electric wind velocity can be obtained by using the new multiple bipolar DBD plasma actuator. © Science China Press and Springer-Verlag Berlin Heidelberg 2013. (12 refs.)Main Heading: Dielectric devicesControlled terms: Actuators - Dynamics - Electric discharges - Flow control - Plasma diagnostics - PlasmasUncontrolled terms: Dielectric barrier - Dielectric barrier discharges - Large-scale flows - Mutual interaction - Particle image velocimetries - PIV - Plasma actuator - Reverse dischargesClassification Code: 631.1 Fluid Flow, General - 632 Hydraulics, Pneumatics and Related Equipment, and Fluidics - 701.1 Electricity: Basic Concepts and Phenomena - 704 Electric Components and Equipment - 714 Electronic Components and Tubes - 931.1 Mechanics - 932.3 Plasma Physics

Database: Compendex

Person re-identification by bidirectional projection

Liu, Lina1; Lu, Xiaoqiang1; Yuan, Yuan1; Li, Xuelong1 Source: ACM International Conference Proceeding Series, p 1-5, 2014, ICIMCS 2014 - Proceedings of the 6th International Conference on Internet Multimedia Computing and Service; ISBN-13: 9781450328104; DOI: 10.1145/2632856.2632887; Conference: 6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014, July 10, 2014 - July 12, 2014; Sponsor: National Natural Foundation of China; SIGMM China Chapter; Xiamen University;

Abstract: Person re-identification plays an important role in video surveillance system. It can be regarded as an image retrieval process which aims to find the same person in multi-camera networks. Many existing methods learn a pairwise similarity measure by mapping the raw feature to a latent subspace to make the data more discriminative. However, most of these methods project all the data into the same subspace ignoring the different characteristics that the same person and different person hold. To solve the aforementioned problem, a pairwise based method is proposed by projecting the raw feature onto two discriminative subspaces according to whether a image pair is of the same class. The proposed method constructs a relative and pairwise model by using the logistic loss function to give a soft measure of the pairwise loss. Meanwhile, a trace norm regularization is used to create the convexity of the objective function, which also help to limit the dimension of the subspaces. Experiments carried on the benchmark dataset VIPeR show that the proposed model obtains better results compared with state-of-the-art methods. Copyright 2014 ACM. (20 refs.)Main Heading: Security systemsControlled terms: Internet - Network securityUncontrolled terms: Benchmark datasets - Bidirectional projection - Multi-camera networks - Objective functions - Person re identifications - State-of-the-art methods - Video surveillance - Video surveillance systemsClassification Code: 723 Computer Software, Data Handling and Applications - 914.1 Accidents and Accident Prevention

Database: Compendex

Synthesis and optical properties of neodymium 4, 4'-dimethyl-2, 2'-bipyridine complex for liquid laser media

Zhao, Peng-Fei1; She, Jiang-Bo1; Li, Dong-Dong1, 2; Nie, Rong-Zhi1; Peng, Bo1, 3 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 2, February 2014

; ISSN: 10044213; DOI: 10.3788/gzxb20144302.0216001; Article number: 0216001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an 710119, China2 School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710061, China3 Institute of Advanced Materials, Nanjing University of Posts and Telecommunications, Nanjing 210003, China

Abstract: A novel neodymium pentafluoropropionate complex, Nd(C<inf>2</inf>F<inf>5</inf>COO)<inf>3</inf>·Dmbp (Dmbp: 4, 4'-dimethyl-2, 2'-bipyridine), was synthesized and characterized by elemental analysis, Fourier transform infrared spectra. The optical porperties of the liquid medium which was abtained by dissolving Nd(C<inf>2</inf>F<inf>5</inf>COO)<inf>3</inf>·Dmbp in N, N-dimethylformamide was investigated. Based on absorption and luminescence spectra of Nd(C<inf>2</inf>F<inf>5</inf>COO)<inf>3</inf>·Dmbp in DMF, as well as Judd-Ofelt theory, the three intensity parameters Ω<inf>t</inf>(t=2, 4, 6) and emission cross-section were calculated and analyzed The emission cross-section of 4F<inf>3/2</inf>→4I<inf>11/2</inf> fluorescence transition of Nd3+ion was 5.2×10-20cm2, and comparable with some laser glasses, which indicated good radiative properties of this neodymium complex in liquid matrix. According to the photoluminescence spectra, Nd(C<inf>2</inf>F<inf>5</inf>COO)<inf>3</inf>·Dmbp complex will be a promising material for optical gain material in the future. (10 refs.)Main Heading: NeodymiumControlled terms: Liquid lasers - Liquids - Organic solvents - PhotoluminescenceUncontrolled terms: Emission cross-section - Fluorescence transitions - Fourier transform infrared spectra - Intensity parameters - Luminescence spectrum - N ,N-Dimethylformamide - Photoluminescence spectrum - Radiative propertiesClassification Code: 547.2 Rare Earth Metals - 741.1 Light/Optics - 744.3 Liquid Lasers - 803 Chemical Agents and Basic Industrial Chemicals - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

Improving level set method for fast auroral oval segmentation

Yang, Xi1; Gao, Xinbo1; Tao, Dacheng2; Li, Xuelong3 Source: IEEE Transactions on Image Processing, v 23, n 7, p 2854-2865, July 2014

; ISSN: 10577149; DOI: 10.1109/TIP.2014.2321506; Article number: 6810012;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 State Key Laboratory of Integrated Services Networks, School of Electronic Engineering, Xidian University, Xi'an 710071, China2 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology, 235 Jones Street, Ultimo, NSW 2007, Australia3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Auroral oval segmentation from ultraviolet imager images is of significance in the field of spatial physics. Compared with various existing image segmentation methods, level set is a promising auroral oval segmentation method with satisfactory precision. However, the traditional level set methods are time consuming, which is not suitable for the processing of large aurora image database. For this purpose, an improving level set method is proposed for fast auroral oval segmentation. The proposed algorithm combines four strategies to solve the four problems leading to the high-time complexity. The first two strategies, including our shape knowledge-based initial evolving curve and neighbor embedded level set formulation, can not only accelerate the segmentation process but also improve the segmentation accuracy. And then, the latter two strategies, including the universal lattice Boltzmann method and sparse field method, can further reduce the time cost with an unlimited time step and narrow band computation. Experimental results illustrate that the proposed algorithm achieves satisfactory performance for auroral oval segmentation within a very short processing time. © 2014 IEEE. (45 refs.)Main Heading: Image segmentationControlled terms: Computational complexity - Computational fluid dynamics - Drop breakup - Evolutionary algorithms - Knowledge based systems - Level measurement - Numerical methodsUncontrolled terms: Auroral oval - Lattice Boltzmann method - Reinitialization - shape knowledge - Sparse field methodClassification Code: 721.1 Computer Theory, Includes Formal Logic, Automata Theory, Switching Theory, Programming Theory - 723 Computer Software, Data Handling and Applications - 921 Mathematics - 921.6 Numerical Methods - 931.2 Physical Properties of Gases, Liquids and Solids - 943.2 Mechanical Variables Measurements

Database: Compendex

Raman spectroscopy and periodic surface structures of Mg:ZnO thin film fabricated by femtosecond laser pulses

Wang, Hongying1, 2; Cheng, Zhen1; Cheng, Guanghua3; Ma, Fei4; Li, Yuanyuan1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9126, 2014, Nanophotonics V

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410747; DOI: 10.1117/12.2051212; Article number: 91261X; Conference: Nanophotonics V, April 13, 2014 - April 17, 2014; Sponsor: Brussels Photonics Team (B-PHOT); Brussels-Capital Region; Fonds Wetenschappelijk Onderzoek (FWO); The Society of Photo-Optical Instrumentation Engineers (SPIE); Ville de Bruxelles;

Publisher: SPIEAuthor affiliation: 1 School of Physics and Mechathronic Engineering, Xi'an University of Arts and Science, Xi'an 710065, China2 Department of Applied Physics and Photonics, Vrije Universiteit Brussel, Brussels Photonics Team B-PHOT, Pleinlaan 2, 1050 Brussels, Belgium3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics, Precision Mechanics of Chinese Academy of Sciences, Xi'an Shaanxi 710119, China4 State Key Laboratory for Mechanical Behavior of Materials, Xi'An Jiaotong University, Xi'an 710049, Shaanxi, China

Abstract: Mg doped ZnO thin films were prepared by magnetron sputtering and were irradiated by linearly polarized femtosecond laser pulse. Scanning electron microscopy (SEM) characterizations illustrated that regularly arranged nanoripples appeared on the ablation area with the period perpendicular to the polarization direction in the range of 250 nm~570 nm, but parallel to the polarization direction in the range of 2.2 μm~2.5 μm. The redshift of Raman peaks was observed at the central ablation area of the nanoripples, while, both blueshift and redshift were found at the edge area, which could be ascribed to the defects as well as the nanoripple structure. © 2014 SPIE. (28 refs.)Main Heading: Ultrashort pulsesControlled terms: Ablation - Metallic films - Nanophotonics - Optical films - Polarization - Scanning electron microscopy - Ultrafast lasersUncontrolled terms: Ablation area - Linearly polarized - Mg-doped ZnO - MgZnO - Nano-ripples - Periodic surface structures - Polarization direction - ZnO thin filmClassification Code: 531 Metallurgy and Metallography - 539 Metals Corrosion and Protection; Metal Plating - 641.2 Heat Transfer - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General

Database: Compendex

Optical system design of Lander camera with focusing type

He, Ying-Hong1; Yang, Jian-Feng1; Ma, Xiao-Long1; Lü, Juan1; Xue, Bin1; Li, Ting1; Jiao, Ying1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 4, April 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144304.0422004; Article number: 0422004;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: A optical system of lander optical payload was designed for the requirement of focusing on objects. A noval focusing type was made that the optical system could keep fixed focal length during focusing. An approaching telecentric optical structure is designed, the optical system was made up of front fixing lens unit and rear focusing lens unit. The front fixing lens is a kind of afocal optical system. The rear focusing lens is at the back of fixing lens unit. The optical can image objects from 0.8 m to infinity in focus by moving rear focusing lens unit. The optical system with spectral range from 400 to 1 000 nm, fixed focal length of 50 mm and F number of 8 can focus on objects located within the range of 0.8 meter to infinity. At last, The modulation transfer function of the optical system can reach to diffraction limit, and distortion is less 1%. The image quality can meet the requirement to the optical system. By the analysis of optical system tolerance, the optical system can keep good imaging quality after fabrication. The optical system can be used to explore moon, mars and asteroids. (15 refs.)Main Heading: Optical systemsControlled terms: Cameras - Diffraction - Focusing - Image quality - Lenses - Optical designUncontrolled terms: Deep-space exploration - Diffraction limits - Focusing system - Mapping camera - Optical payloads - Optical structures - System tolerance - Wide spectrumClassification Code: 741 Light, Optics and Optical Devices - 742.2 Photographic Equipment

Database: Compendex

Shrink image by feature matrix decomposition

Wang, Qi1; Li, Xuelong2 Source: Neurocomputing, v 140, p 162-171, September 22, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2014.03.025;

Publisher: ElsevierAuthor affiliation: 1 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: With the development of multimedia technology, image resizing has been raised as a question when the aspect ratio of an examined image should be displayed on a device with a different aspect ratio. Traditional nonuniform scaling for tackling this problem will lead to distortion. Therefore, content-aware consideration is mostly incorporated in the designing procedure. Such methods generally defines an energy function indicating the importance level of image content. The more important regions would be retained in the resizing procedure and distortion could be avoided consequently. The definition of the related energy function is thus the critical factor that directly influences the resizing results. In this work, we explore the definition of energy function from another aspect, matrix decomposition of Low-rank Representation. In our processing, a feature matrix that reflects the texture prior of object contour is firstly constructed. Then the matrix is decomposed into a low-rank one and sparse one. The energy function for resizing is then inferred from the sparse one. We illustrate the proposed method through seam carving framework and image shrinkage operation. Experiments on a dataset containing 1000 images demonstrate the effectiveness and robustness of the proposed method. © 2014 Elsevier B.V. (41 refs.)Main Heading: Image codingControlled terms: Artificial intelligence - Aspect ratio - Computer vision - Learning systems - Multimedia systemsUncontrolled terms: Energy functions - Image resizing - Low-rank representations - Matrix decomposition - Multimedia technologies - Non-uniform scaling - Seam carving - Sparse codingClassification Code: 723.4 Artificial Intelligence - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 943 Mechanical and Miscellaneous Measuring Instruments

Database: Compendex

Noise model and simulation analysis of the low noise pre-amplifier of CCD camera

Chen, Zhi1; Qiu, Yuehong1; Wen, Yan1; Jiang, Baotan1; Yao, Dalei1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9142, 2014, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410938; DOI: 10.1117/12.2054240; Article number: 91420M; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013, October 20, 2013 - October 29, 2013; Sponsor: Chinese Society of Astronautics; ducation, Shanghai Jiaotong University; Education and Training Department, China; Key Laboratory for Laser Plasmas, Ministry of E; Ordnance Society; Photoelectronic Technology Professional Committee,;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, 710119, China

Abstract: The low noise video process chain design is the important guarantee of realization of CCD detection performance. While pre-amplifier locate in the front end of the video signal process of CCD camera, so the low noise preamplifier design is the important guarantee of realization of low noise CCD camera. Firstly, calculate the bandwidth and equivalent noise bandwidth of video process chain of CCD camera. Secondly, design the preamplifier circuit and build the noise model of the preamplifier. Thirdly, according to the noise model calculation the noise of the pre-amplifier. Lastly, build the noise simulation model of the preamplifier. Through theoretical calculation and PSPICE simulation result predict the noise level of the preamplifier of the CCD.The noise level of the preamplifier less than 2 electronics, it meets specification requirement. © 2014 Copyright SPIE. (10 refs.)Main Heading: Computer simulationControlled terms: Amplifiers (electronic) - Bandwidth - CCD cameras - Chains - Design - Optical image storage - Remote sensing - Signal processing - SPICEUncontrolled terms: Low noise - Low noise preamplifiers - Noise modeling - P-Spice simulation - Preamplifier circuit - simulation - Specification requirement - Theoretical calculationsClassification Code: 408 Structural Design - 602.1 Mechanical Drives - 713.1 Amplifiers - 714.2 Semiconductor Devices and Integrated Circuits - 716.1 Information Theory and Signal Processing - 723.5 Computer Applications - 731.1 Control Systems - 741.3 Optical Devices and Systems

Database: Compendex

Efficient dictionary learning for visual categorization

Tang, Jun1; Shao, Ling2; Li, Xuelong3 Source: Computer Vision and Image Understanding, v 124, p 91-98, July 2014

; ISSN: 10773142, E-ISSN: 1090235X; DOI: 10.1016/j.cviu.2014.02.007;

Publisher: Academic Press Inc.Author affiliation: 1 Key Laboratory of Intelligent Computing and Signal Processing, Ministry of Education, Anhui University, Huangshan Road, Hefei 230039, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, United Kingdom3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We propose an efficient method to learn a compact and discriminative dictionary for visual categorization, in which the dictionary learning is formulated as a problem of graph partition. Firstly, an approximate kNN graph is efficiently computed on the data set using a divide-and-conquer strategy. And then the dictionary learning is achieved by seeking a graph topology on the resulting kNN graph that maximizes a submodular objective function. Due to the property of diminishing return and monotonicity of the defined objective function, it can be solved by means of a fast greedy-based optimization. By combing these two efficient ingredients, we finally obtain a genuinely fast algorithm for dictionary learning, which is promising for large-scale datasets. Experimental results demonstrate its encouraging performance over several recently proposed dictionary learning methods. © 2014 Elsevier Inc. All rights reserved. (32 refs.)Main Heading: TopologyControlled terms: Image classificationUncontrolled terms: Dictionary learning - Discriminative dictionaries - Divide and conquer - Graph construction - Large-scale datasets - Objective functions - Submodular optimizations - Visual categorizationClassification Code: 716 Telecommunication; Radar, Radio and Television - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Development of a chip-based ingroove microplasma source: Design, characterization, and diagnostics

Li, Xuemei1; Tang, Jie2; Meng, Fanying1; Yuan, Xin1; Yan, Yanyue1; Zhao, Zhongjun1; Duan, Yixiang1 Source: Applied Physics Letters, v 104, n 10, March 10, 2014

; ISSN: 00036951; DOI: 10.1063/1.4867484; Article number: 103502;

Publisher: American Institute of Physics Inc.Author affiliation: 1 Research Center of Analytical Instrumentation, College of Chemistry, College of Life Science Sichuan University, Chengdu, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: A chip-based ingroove microplasma source was designed for molecular emission spectrometry by using a space-confined direct current duct in air. The voltage-current characteristics of different size generators, emission spectroscopy of argon were discussed, respectively. It is found that the emission intensity of excited Ar and N<inf>2</inf> approaches its maximum near the cathode, while OH and O peaks most likely appear close to the anode. The electron density, electronic excitation temperature, rotational temperature, and vibrational temperature of the argon plasma were also calculated. More importantly, the chip-based ingroove microplasma shows much better stability compared with its counterparts. © 2014 AIP Publishing LLC. (40 refs.)Main Heading: Plasma devicesControlled terms: Emission spectroscopy - MetamaterialsUncontrolled terms: Different sizes - Electronic excitation temperature - Emission intensity - Microplasma source - Molecular emissions - Rotational temperature - Vibrational temperature - Voltage-current characteristicsClassification Code: 801 Chemistry - 932.3 Plasma Physics - 951 Materials Science

Database: Compendex

Passively Q-switched lasers at 1.06 μm with graphene oxide and carbon nanotubes D<inf>2</inf>O dispersion

Feng, Tianli1; Zhao, Shengzhi1; Yang, Kejian1; Zhao, Jia1; Li, Guiqiu1; Li, Dechun1; Qiao, Wenchao1; Li, Tao1; Chen, Xintian1; Liu, Cheng1; Wang, Yonggang2 Source: Optical Materials, v 36, n 7, p 1270-1273, May 2014

; ISSN: 09253467; DOI: 10.1016/j.optmat.2014.03.014;

Publisher: ElsevierAuthor affiliation: 1 School of Information Science and Engineering, Shandong University, Jinan, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We have investigated the passive Q-switching characteristics of graphene oxide (GO) and single walled carbon nanotubes (SWCNTs) D<inf>2</inf>O (heavy water, deuteroxide) based on a diode-pumped YVO<inf>4</inf>/Nd:YVO<inf>4</inf> laser for the first time as far as we know. By using 20 mg/10 ml GO D <inf>2</inf>O dispersion, pulses with minimum duration of 344 ns under a repetition rate of 550 kHz were obtained. With 0.3 mg/10 ml SWCNTs D <inf>2</inf>O dispersion, a maximum pulse energy of 1.2 μJ with duration of 530 ns was achieved at a repetition rate of 178 kHz. © 2014 Elsevier B.V. All rights reserved. (19 refs.)Main Heading: DispersionsControlled terms: Carbon nanotubes - Graphene - Heavy water - Pumping (laser) - Q switching - Single-walled carbon nanotubes (SWCN)Uncontrolled terms: Diode-pumped - Graphene oxides - Passive Q-switching - Passively Q-switched lasers - Pulse energies - Repetition rate - Single-walled carbon nanotube (SWCNTs)Classification Code: 744.1 Lasers, General - 744.8 Laser Beam Interactions - 761 Nanotechnology - 804 Chemical Products Generally - 951 Materials Science

Database: Compendex

Nonlinear absorption of SWNT film and its effects to the operation state of pulsed fiber laser

Li, Xiaohui1; Wang, Yonggang2; Wang, Yishan2; Zhao, Wei2; Yu, Xuechao1; Sun, Zhipei3; Cheng, Xueping4; Yu, Xia5; Zhang, Ying5; Wang, Qi Jie1 Source: Optics Express, v 22, n 14, p 17227-17235, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.017227;

Publisher: Optical Society of American (OSA)Author affiliation: 1 Division of Microelectronics, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Ave., 639798, Singapore, Singapore2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Department of Micro- and Nanosciences, Aalto University, PO Box 13500, FI-00076 Aalto, Finland4 JPT Electronics Pte. Ltd, Singapore, Singapore5 Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, 638075 Singapore, Singapore

Abstract: We study a single-wall carbon nanotube (SWNT) Polyvinyl alcohol (PVA) composite as a saturable absorber (SA) for pulse generation in Yb-doped fiber lasers. The saturable absorption and optical limiting (OL) characteristics of the SWNT device are investigated. By combing these two nonlinear effects, we find out for the first time, to the best of our knowledge, that mode-locking can be obtained in the dissipative soliton regime at low pumping followed by Q-switching at high pumping, which is quite different from conventional pulse dynamic evolutions. The Qswitched state operating at higher pump powers is due to the OL effect. The inverted operating fiber laser can be applied in various potential applications such as versatile material processing, optical communication and radar system etc. © 2014 Optical Society of America. (41 refs.)Main Heading: Optical pumpingControlled terms: Fiber lasers - Nonlinear optics - Optical communication - Pulse generators - Pumps - Radar systems - Saturable absorbers - Semiconductor quantum wells - SolitonsUncontrolled terms: Dissipative solitons - Material processing - Nonlinear absorptions - Optical limiting - Poly (vinyl alcohol) (PVA) - Pulsed fiber lasers - Saturable absorption - Yb-doped fiber lasersClassification Code: 618.2 Pumps - 713.4 Pulse Circuits - 714.2 Semiconductor Devices and Integrated Circuits - 716.2 Radar Systems and Equipment - 717.1 Optical Communication Systems - 741 Light, Optics and Optical Devices - 744.1 Lasers, General - 744.4 Solid State Lasers - 931.3 Atomic and Molecular Physics

Database: Compendex

Intracavity-frequency-doubled Q-switched and mode-locked Nd:Lu <inf>0.15</inf>Y<inf>0.85</inf>VO<inf>4</inf>/KTP green laser with AO modulator and central SESAM

Feng, Tianli1; Zhao, Shengzhi1; Yang, Kejian1; Li, Guiqiu1; Li, Dechun1; Zhao, Jia1; Zhao, Bin2; Wang, Yonggang3 Source: Optik, v 125, n 12, p 2739-2744, June 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.01.009;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 School of Information Science and Engineering, Shandong University, Jinan 250100, China2 College of Chemistry and Chemical Engineering, Fuzhou University, Fuzhou 350108, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: By using mixed crystal Nd:Lu<inf>0.15</inf>Y<inf>0.85</inf>VO<inf>4</inf> as laser medium, KTP as frequency-doubling crystal, a diode-pumped intracavity-frequency-doubled Q-switched and mode-locked (QML) Nd:Lu <inf>0.15</inf>Y<inf>0.85</inf>VO<inf>4</inf>/KTP green laser with acousto-optic (AO) modulator and central semiconductor saturable absorption mirror (C-SESAM) is realized by using a V-type cavity. The QML laser characteristics such as the pulse width, single-pulse energy, have been measured for different modulation frequencies of the AO modulator. In comparison with the singly passively QML green laser with central SESAM, the doubly QML green laser can generate more stable and shorter pulses with higher peak power. Based on the coupled rate equations for a diode-pumped doubly QML green laser with AO and C-SESAM, in which the saturated absorption mechanism of C-SESAM is considered, the recurrence relation of the relative amplitude of the mode-locking pulses is given and the related numerical simulations are in good agreement with the experimental results. © 2014 Elsevier GmbH. All rights reserved. (26 refs.)Main Heading: Mode-locked fiber lasersControlled terms: Frequency doublers - Locks (fasteners) - Pumping (laser) - Q switching - Semiconductor saturable absorber mirrorsUncontrolled terms: Central SESAM - Coupled rate equations - Frequency-doubling crystals - Green laser - Intra cavity frequency doubling - Mixed crystals - Modulation frequencies - Semiconductor saturable absorption mirrorClassification Code: 601.3 Mechanisms - 713.5 Electronic Circuits Other Than Amplifiers, Oscillators, Modulators, Limiters, Discriminators or Mixers - 744.1 Lasers, General - 744.8 Laser Beam Interactions

Database: Compendex

Learning hash functions using sparse reconstruction

Yuan, Yong1; Lu, Xiaoqiang1; Li, Xuelong1 Source: ACM International Conference Proceeding Series, p 14-18, 2014, ICIMCS 2014 - Proceedings of the 6th International Conference on Internet Multimedia Computing and Service; ISBN-13: 9781450328104; DOI: 10.1145/2632856.2632883; Conference: 6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014, July 10, 2014 - July 12, 2014; Sponsor: National Natural Foundation of China; SIGMM China Chapter; Xiamen University;

Abstract: Approximate nearest neighbor (ANN) search is becoming an increasingly important technique in large-scale problems. Recently many approaches have been developed due to fast query and low storage cost. Although most of them have realized the importance of the data structure, they neglected the sparse relationship of the data. To build a balance between the adjusted covariance matrix and the minimum reconstruction error of data points, this paper proposes a novel method based on sparse reconstruction to learn more compact binary codes under l2;1-norm constraint. Experiments demonstrate that the proposed method, named as sparse reconstruction hashing, outperforms several other state-of-the-art methods when tested on a few benchmark datasets. Copyright 2014 ACM. (13 refs.)Main Heading: Hash functionsControlled terms: Covariance matrix - Digital storage - InternetUncontrolled terms: ANN - Approximate nearest neighbors (ANN) - Hashing - Image search - Large-scale problem - Reconstruction error - Sparse reconstruction - State-of-the-art methodsClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 722.1 Data Storage, Equipment and Techniques - 723 Computer Software, Data Handling and Applications - 921 Mathematics - 922 Statistical Methods

Database: Compendex

A design of real-time image processing platform based on TMS320C6678

Qu, Lei1, 2; Tian, Yan1; Liu, Jun1, 2 Source: Advanced Materials Research, v 971-973, p 1454-1458, 2014, New Technologies for Engineering Research and Design in Industry

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038351412; DOI: 10.4028/www.scientific.net/AMR.971-973.1454; Conference: 2014 International Conference on Mechatronics and Intelligent Materials, MIM 2014, May 18, 2014 - May 19, 2014; Sponsor: CEIS; IFST; National Chin-Yi University of Technology; Scientific.Net;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 XI'AN Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: For real time target detection, identification and tracking in high frame rates, large field of view images, a real-time image processing system is designed. A TMS320C6678 DSP runs as the chief arithmetic processor of this system and FPGA as the secondary controller. C6678 is compared with the same series C6414 in image compression algorithm test. Experimental results show that the new system has a more effective construct, and higher reliability, and can provide a platform for the new high-speed image processing. © (2014) Trans Tech Publications, Switzerland. (7 refs.)Main Heading: Image processingControlled terms: Digital signal processing - Field programmable gate arrays (FPGA)Uncontrolled terms: C6414 - C6678 - DSP - High frame rate - High-speed image processing - Image compression algorithms - Large field of views - Real-time image processingClassification Code: 721.3 Computer Circuits - 722.4 Digital Computers and Systems - 741 Light, Optics and Optical Devices

Database: Compendex

Tunable slow light based on plasmon-induced transparency in dual-stub-coupled waveguide

Wang, Guoxi1; Zhang, Wenfu1; Gong, Yongkang1; Liang, Jian1 Source: IEEE Photonics Technology Letters, v 27, n 1, p 89-92, January 1, 2015

; ISSN: 10411135; DOI: 10.1109/LPT.2014.2362293; Article number: 6918431;

Abstract: We investigate the plasmon-induced transparency (PIT) effect in dual-stub-coupled metal-insulator-metal waveguide. The transmission line theory is employed to analyze the relationship between the transmission properties and geometrical parameters. It is found that by incorporating tunable refractive index materials with the proposed structure, a tunable PIT and slow light effect can be obtained in a constant stub separation design. The theoretical results show that a shift of 70 THz in the central wavelengths of transparency window can be obtained when the refractive index of the dielectric varies. In addition, the group index can be tuned from 24 to 36, which provides an effective method to adjust the slow light properties in the proposed waveguide. This letter opens up the possibility for the realization of tunable slow light devices in highly integrated optical circuits. (26 refs.)Main Heading: Slow lightControlled terms: Electric lines - Metal insulator boundaries - Photonic integration technology - Plasmons - Refractive index - Transparency - WaveguidesUncontrolled terms: Central wavelength - Coupled waveguides - Induced transparency - Integrated optical circuit - Metal-insulator-metal waveguides - Slow-light devices - Surface plasmons - Transmission propertyClassification Code: 706.2 Electric Power Lines and Equipment - 712.1 Semiconducting Materials - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 741.1 Light/Optics

Database: Compendex

Hierarchical incorporation of shape and shape dynamics for flying bird detection

Zhang, Jun1; Xu, Qunyu1; Cao, Xianbin1; Yan, Pingkun2; Li, Xuelong2 Source: Neurocomputing, v 131, p 179-190, May 5, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.10.026;

Publisher: ElsevierAuthor affiliation: 1 National Key Lab of CNS/ATM, School of Electronics and Information Engineering, Beihang University, Xueyuan Rd. 37, Haidian District, Beijing 100191, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Lab of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shanxi, China

Abstract: Flying bird detection (FBD) is critical in avoiding bird-aircraft collisions. Most existing approaches rely on motion detection to identify the flying bird, since it is a typical moving object. However, when there exist other moving objects, those methods often fail to distinguish flying birds from those objects due to the insufficiency of feature description. In this paper, we introduce a novel hierarchical feature model exploiting shape and shape dynamics to improve the ability of representing a flying bird, and then apply it to the FBD problem. As the shape of a flying bird is very distinctive in geometric structures and could provide discriminating spatial information, an improved shape context feature descriptor is proposed at the lower level to capture the spatial relations in bird shape. Then the shape descriptor is extended into the spatio-temporal domain and a shape dynamics description is built at the higher level, in which a 4-state Markovian model is adopted and is learned from training sequences. Moreover, to build a mapping from the lower level to the higher level of the hierarchy, a shape similarity index (SSI) based matching mechanism is designed. We apply these two-level features for detecting flying bird for improved safety of aircrafts flying at low-altitude. The experimental results show that the proposed method is effective and outperforms three other existing vision-based FBD approaches. © 2013 Elsevier B.V. (42 refs.)Main Heading: Flight dynamicsControlled terms: Birds - Markov processesUncontrolled terms: Bird detection - Bird-aircraft collisions - Hierarchical features - Shape dynamics - Shape similarityClassification Code: 461 Bioengineering and Biology - 821 Agricultural Equipment and Methods; Vegetation and Pest Control - 822 Food Technology - 922.1 Probability Theory - 931.1 Mechanics

Database: Compendex

A low-power magnetic-field-assisted plasma jet generated by dielectric-barrier discharge enhanced direct-current glow discharge at atmospheric pressure

Jiang, Weiman1; Tang, Jie1; Wang, Yishan1; Zhao, Wei1; Duan, Yixiang1, 2 Source: Applied Physics Letters, v 104, n 1, January 6, 2014

; ISSN: 00036951; DOI: 10.1063/1.4861162; Article number: 013505;

Publisher: American Institute of PhysicsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics of CAS, Xian 710119, China2 Research Center of Analytical Instrumentation, Sichuan University, Chengdu 610064, China

Abstract: A magnetic field is introduced to the dielectric-barrier discharge enhanced direct-current glow discharge for efficient plasma generation, with the discharge power of 2.7 W and total energy consumption reduced to 34 of the original. By spatially examining the emission spectra and plasma temperature, it is found that their peaks shift from edges to the center and the negative and anode glows merge into the positive column and disappear, accompanied by improvement of uniformity and chemical activity of the enlarged plasma. This lies in the enhancement of ionization in the curved and lengthened electron path and the dispersion of discharge domains. © 2014 AIP Publishing LLC. (24 refs.)Main Heading: Plasma diagnosticsControlled terms: Atmospheric pressure - Emission spectroscopy - Energy utilization - Glow discharges - PlasmasUncontrolled terms: Chemical activities - Dielectric-barrier discharges - Discharge power - Emission spectrums - Plasma generation - Plasma temperature - Positive column - Total energy consumptionClassification Code: 443.1 Atmospheric Properties - 525.3 Energy Utilization - 701.1 Electricity: Basic Concepts and Phenomena - 801 Chemistry - 932.3 Plasma Physics

Database: Compendex

Infrared emission properties of Dy3 +-doped and Dy 3 +,Tm3 +-codoped chalcohalide glasses

Gu, Shaoxuan1; Pi, Daoxian1; Tao, Haizheng1; Zeng, Qi1; Zhao, Xiujian1; Guo, Haitao2; Chen, Hongyan3 Source: Journal of Non-Crystalline Solids, v 383, p 205-208, January 1, 2014

; ISSN: 00223093; DOI: 10.1016/j.jnoncrysol.2013.05.041;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Silicate Materials for Architectures (Wuhan University of Technology), Wuhan, Hubei 430070, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, Shaanxi 710119, China3 Institute of Publication Science, Book Concern of chang'An University, Xi'an, Shaanxi 710064, China

Abstract: Series of 76GeS<inf>2</inf>·19Ga<inf>2</inf>S<inf>3</inf>· 5AgCl (GGA) chalcohalide glasses doped with or codoped with Dy3 +, Tm3 + were prepared in this work. Systematical detection of absorption and emission spectra in the near-infrared and mid-infrared region was conducted. For the Dy3 + sole-doped GGA chalcohalide glasses, mainly due to the relatively low efficiency of pumping absorption and poor radiative transition probabilities of mid-infrared emissions, the mid-infrared emissions were hardly to be detected. Through the codoping of Tm3 + with high concentration, several intrinsical processes including the enhancement of pumping absorptive efficiency at 808 nm, cross relaxation process of Tm 3 +: 3H<inf>4</inf> + 3H<inf>6</inf> → 3F<inf>4</inf> + 3F<inf>4</inf> and energy transfer process of Tm3 +: 3F<inf>4</inf> → Dy3 +: 6H<inf>11/2</inf> are carried out, therefore relatively strong mid-infrared emissions at about 2900 and 4300 nm have been clearly observed. © 2013 Elsevier B.V. All rights reserved. (15 refs.)Main Heading: Doping (additives)Controlled terms: Emission spectroscopy - Energy transfer - Glass - Infrared devices - Metal ionsUncontrolled terms: Absorption and emission spectra - Chalcohalide glass - Cross-relaxation process - Energy transfer process - Infrared emission property - Mid-infrared emission - Radiative transition probabilities - Rare earth ionsClassification Code: 533 Ore Treatment and Metal Refining - 641.2 Heat Transfer - 741.3 Optical Devices and Systems - 801 Chemistry - 812.3 Glass

Database: Compendex

Compact symmetric-type modulating technique of electron packet width

Wang, Chao1; Li, Hao1, 2; Tian, Jinshou1 Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams, v 26, n 3, March 2014; Language: Chinese

; ISSN: 10014322; DOI: 10.3788/HPLPB201426.034007; Article number: 034007;

Publisher: Editorial Office of High Power Laser and Particle BeamsAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: Aiming at the urgent needs for modulation technique of electronic packet width, we propose a compact symmetric type electron packet width modulation technique. The core of which is the introduction of the carefully chosen alternating electric field, which imposes differential energy modulation on electrons of different part in the electron packet, achieving the purpose of modulating the width of the electron packet. The details are given, including the choosing of the alternating electric field, pulse modulation amplitude relationship and the transverse confinement of the axial magnetic field. The requirements for both compression and broadening modulation in different types of modulating electric field are obtained. The example demonstrates its validity. (14 refs.)Main Heading: ElectronsControlled terms: Electric field effects - Frequency modulationUncontrolled terms: Alternating electric field - Compact - Differential energy - Modulating techniques - Modulation amplitudes - Modulation techniques - Symmetric type - Transverse confinementClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications

Database: Compendex

Study on 1.19 and 1.36 μm fluorescence for Ho-doped water-free fluorotellurite glasses

He, Jianli1, 2; Zhan, Huan1, 2; Zhou, Zhiguang1; Zhang, Aidong1; Lin, Aoxiang1 Source: Optics Communications, v 320, p 68-72, June 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.01.040;

Abstract: To find more efficient materials for optical amplifiers, near-infrared spectroscopic properties of Ho-doped water-free fluorotellurite glasses 60TeO<inf>2</inf>-30ZnF<inf>2</inf>-10NaF (mol%, TZNF60) were investigated. Excited by an OPO laser system at 534 nm, intense 1.19 (Ho: I <inf>6</inf>→I<inf>8</inf>) and 1.36 μm (Ho: (S<inf>2</inf>,F)→I) emissions in Ho3+ doped TZNF60 glasses were observed, and long directly measured lifetime at 1.19 μm is of 750-950 μs and of 32-44 μs for 1.36 μm, respectively, resulting from the absence of OH groups and the low phonon energy with the addition fluorides into tellurite oxide glasses. Among all the made Ho-TZNF60 samples, 1.00HoO-TZNF60 glass presents the strongest fluorescence with larger emission cross-sections of (0.63, 0.22)×10 cm at 1.2 and 1.36 μm, respectively. Therefore, it is regarded as a promising material for the development of optical amplification and laser operation at the relatively unexplored 1.2 and 1.36 μm regions. © 2013 Elsevier B.V. All rights reserved. © 2014 Elsevier B.V. All rights reserved. (25 refs.)Main Heading: GlassControlled terms: Fluorescence - Holmium - Light amplifiers - Tellurium compoundsUncontrolled terms: Emission cross section - Fiber materials - Fluoro-tellurite glass - Laser operations - Low phonon energies - Near Infrared - Optical amplifications - Spectroscopic propertyClassification Code: 547.2 Rare Earth Metals - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 804.1 Organic Compounds - 812.3 Glass

Database: Compendex

Analyses on limitations of coherent field imaging principle

Si, Qing-Dan1, 2; Luo, Xiu-Juan1; Zeng, Zhi-Hong1, 2 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 10, May 20, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.104203; Article number: 104203;

Publisher: Institute of Physics, Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: The theoretical basis of coherent field imaging technique (also called the Fourier telescopy) is reconsidered. The limitations of the technique principle are analyzed by defining the measured object and deriving rigorously mathematical expressions. The reconstructed image of the technique ineluctably contains the gradient information about the object; as a result the technique cannot acquire the reflectivity of the object exactly. The computer simulation verifies the conclusion. Based on the conclusion, the reconstructed image of the technique can be evaluated and three-dimensional coherent field imaging technique may be developed. © 2014 Chinese Physical Society. (12 refs.)Main Heading: Image reconstructionControlled terms: Computer simulation - Imaging techniques - ReflectionUncontrolled terms: Coherent fields - Fourier telescopy - Gradient informations - Mathematical expressions - Reconstructed image - Surface integralsClassification Code: 711 Electromagnetic Waves - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 746 Imaging Techniques

Database: Compendex

Simulation study of rotating double optical wedge vectoring optics path based on Matlab

Guo, Yunzeng1, 2; Yang, Xiaojun1; Yang, Xiaojun1; Jia, Haini1, 2; Wang, Haitao1; Liu, Feng1; Jiang, Zhi3 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 856-860, March 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710126, China2 University of Chinese Academy of Sciences, Beijing 100049, China3 Baicheng Ordnance Test Center of China, Baicheng 137001, China

Abstract: The optical wedge plays a guiding and key role on the processing of high-precision micro-hole drilling by laser pulses. In order to improve the laser micro-hole processing quality, a method was presented to improve the analysis on the impact of the optical wedge on accuracy of laser micro-manufacturing. First the concept of the equivalent of a single wedge vector was proposed. The double wedge vector model was established and analyzed based on the definition of a single wedge vector, and the new method of the vector superposition of the multiple wedges was came up with. Secondly, the simulation software was programmed by using Matlab. The simulation results show the trail of the laser pulses through the double optical wedge. The effect of the quality of the micro-hole caused by the unsynchronization of the motion system is investigated. The deviation quantitative analysis is carried and the formula of calculation the deviation is given. The conclusion is of great value to the performance indicators of designing the controlling system in the high-precision micro-hole drilling by laser pulses. (10 refs.)Main Heading: MATLABControlled terms: Computer software - Error analysis - Laser pulses - Synchronization - VectorsUncontrolled terms: Controlling system - High-precision - Laser drilling - Laser micro-manufacturing - Performance indicators - Processing quality - Simulation software - Simulation studiesClassification Code: 723 Computer Software, Data Handling and Applications - 744.1 Lasers, General - 921 Mathematics - 961 Systems Science

Database: Compendex

A simple method for astigmatic compensation of folded resonator without Brewster window

Qiao, Wen1, 2; Xiaojun, Zhang1, 2; Yonggang, Wang3; Liqun, Sun4; Hanben, Niu2 Source: Optics Express, v 22, n 3, p 2309-2316, February 10, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.002309;

Publisher: Optical Society of AmericaAuthor affiliation: 1 Key Laboratory of Optoelectronic Devices and Systems, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China2 Key Laboratory of Micro-Nano Measuring and Imaging in Biomedical Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China4 State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing 100084, China

Abstract: A folded resonator requires an oblique angle of incidence on the folded curved mirror, which introduces astigmatic distortions that limit the performance of the lasers. We present a simple method to compensate the astigmatism of folded resonator without Brewster windows for the first time to the best of our knowledge. Based on the theory of the propagation and transformation of Gaussian beams, the method is both effective and reliable. Theoretical results show that the folded resonator can be compensated astigmatism completely when the following two conditions are fulfilled. Firstly, when the Gaussian beam with a determined size beam waist is obliquely incident on an off-axis concave mirror, two new Gaussian beam respectively in the tangential and sagittal planes are formed. Another off-axis concave mirror is located at another intersection point of the two new Gaussian beams. Secondly, adjusting the incident angle of the second concave mirror or its focal length can make the above two Gaussian beam coincide in the image plane of the second concave mirror, which compensates the astigmatic aberration completely. A side-pumped continues-wave (CW) passively mode locked Nd:YAG laser was taken as an example of the astigmatically compensated folded resonators. The experimental results show good agreement with the theoretical predictions. This method can be used effectively to design astigmatically compensated cavities resonator of high-performance lasers. © 2014 Optical Society of America. (17 refs.)Main Heading: MirrorsControlled terms: Gaussian beams - Laser mirrors - Neodymium lasers - Passive mode locking - ResonatorsUncontrolled terms: Astigmatic compensation - Concave mirror - Incident angles - Intersection points - ND : YAG lasers - Oblique angles - Passively mode-locked - Sagittal planeClassification Code: 711 Electromagnetic Waves - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 744.4 Solid State Lasers

Database: Compendex

Integrate the original face image and its mirror image for face recognition

Xu, Yong1, 2; Li, Xuelong3; Yang, Jian4; Zhang, David5 Source: Neurocomputing, v 131, p 191-199, May 5, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.10.025;

Publisher: ElsevierAuthor affiliation: 1 Bio-Computing Research Center, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, Guangdong, China2 Key Laboratory of Network Oriented Intelligent Computation, Shenzhen 518055, Guangdong, China3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China4 College of Computer Science and Technology, Nanjing University of Science and Technology, Nanjing, 210094, China5 Biometrics Research Center, Hong Kong Polytechnic University, Hong Kong

Abstract: The face almost always has an axis-symmetrical structure. However, as the face usually does not have an absolutely frontal pose when it is imaged, the majority of face images are not symmetrical images. These facts inspire us that the mirror image of the face image might be viewed as a representation of the face with a possible pose opposite to that of the original face image. In this paper we propose a scheme to produce the mirror image of the face and integrate the original face image and its mirror image for representation-based face recognition. This scheme is simple and computationally efficient. Almost all the representation-based classification methods can be improved by this scheme. The underlying rationales of the scheme are as follows: first, the use of the mirror image can somewhat overcome the misalignment problem of the face image in face recognition. Second, it is able to somewhat eliminate the side-effect of the variation of the pose and illumination of the original face image. The experiments show that the proposed scheme can greatly improve the accuracy of the representation-based classification methods. The proposed scheme might be also helpful for improving other face recognition methods. © 2013 Elsevier B.V. (51 refs.)Main Heading: Face recognitionControlled terms: Biometrics - Mirrors - Pattern recognitionUncontrolled terms: Classification methods - Computationally efficient - Face images - Face recognition methods - Mirror images - Side effect - Sparse representationClassification Code: 461 Bioengineering and Biology - 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 732 Control Devices - 741.3 Optical Devices and Systems

Database: Compendex

Temperature control system for SLD optical source of FOCS

Cao, Hui1, 2; Yang, Yifeng1; Liu, Shangbo1; Xu, Jintao1; Zhao, Wei1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 3, p 920-926, March 2014; Language: Chinese

; ISSN: 10072276;

Abstract: To lower the influence of optical source temperature property on the precision of fiber optic current sensor(FOCS) in high voltage grid, an analog temperature control system was proposed to control the optical source working temperature. According to the designed goal, design process of each key section was introduced. A proper temperature signal bridge was analyzed which could obtain a linear relationship between the output differential voltage and temperature. The mathematical model of the system was established in the frequency domain; the transfer function of the system was calculated; and the parameters of proportional-integral-derivative (PID) controller were analyzed in the time domain. A temperature controller used for FOCS super luminescent diode (SLD) optical source was designed, which was verified by fixed temperature test and temperature cycle test. The results show that by means of the real time temperature control, the accuracy of FOCS is up to 0.2 level which reaches industry requirements. (17 refs.)Main Heading: Temperature controlControlled terms: Luminescence - Mathematical models - Proportional control systems - Transfer functionsUncontrolled terms: Fiber-optic current sensor - Industry requirements - PID controllers - Proportional integral derivative controllers - Real time - Superluminescent diode - Temperature controllers - Temperature cycle testClassification Code: 731.1 Control Systems - 731.3 Specific Variables Control - 741.1 Light/Optics - 921 Mathematics

Database: Compendex

Road vehicle information collection system based on distributed fiber optics sensor

Feng, Li Li1; Wang, Yun Tao1; Ruan, Chi1; Tao, Sheng2 Source: Advanced Materials Research, v 1030-1032, p 2105-2109, 2014

; ISSN: 10226680, E-ISSN: 16628985; ISBN-13: 9783038352488; DOI: 10.4028/www.scientific.net/AMR.1030-1032.2105; Conference: 2nd International Conference on Materials, Transportation and Environmental Engineering, CMTEE 2014, July 30, 2014 - July 31, 2014; Sponsor: ChienKuo Technology University; International Frontiers of science and technology Research Association; National Cheng Kung University; National Chi Nan University; National Chin-Yi University of Technology; National Sun Yan-Sen University; Trans Tech Publications;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, 17 Xinxi Road, Xian; Shanxi, China2 China Academy of Transportation Sciences, Ministry of Communications, 240 Huixinli, Chaoyang District, Beijing, China

Abstract: A novel distributed fiber optics sensor used for road vehicle information collection system was proposed. Optical fiber was fixed on the road surface to be used as the sensing media. The vehicle information such as speed, vehicle type, vehicle weight and traffic flow can be obtained. To increase the sensitivity of such sensor, an optical Fabry-Perot (F-P) fiber interference was used. Sensing optical fiber was designed to be with a metal coating for fiber protection and high performance. Experiment results show that such distributed fiber optics sensor may be with a high performance in transportation area without digging when it is installed on the road surface. © (2014) Trans Tech Publications, Switzerland. (9 refs.)Main Heading: Fiber opticsControlled terms: Environmental engineering - Fabry-Perot interferometers - Fibers - Materials handling - Optical fibers - Roads and streets - Transportation - Vehicles - Weigh-in-motion (WIM)Uncontrolled terms: Fiber optics sensors - Fiber protections - Information collections - Road surfaces - Road vehicles - Sensing optical fiber - Vehicle types - Vehicle weightsClassification Code: 406.2 Roads and Streets - 432 Highway Transportation - 454 Environmental Engineering - 691 Bulk Handling and Unit Loads - 741.1.2 Fiber Optics - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications - 941.3 Optical Instruments - 943.3 Special Purpose Instruments

Database: Compendex

Tunneling control of cavity linewidth narrowing via quantum interference in triangular quantum dot molecules

Tian, Si-Cong1; Wan, Ren-Gang2; Xing, En-Bo1, 3; Tong, Cun-Zhu1; Ning, Yong-Qiang1 Source: Journal of Modern Optics, v 61, n 18, p 1479-1485, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.941431;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China3 Graduate School, Chinese Academy of Sciences, Beijing, China

Abstract: A scheme for tunneling control of cavity linewidth narrowing by quantum interference in triangular-type triple quantum dots (TQDs) is proposed. In such system, quantum interference induced by tunneling between the TQDs can result in the appearance of two transparency windows and a steep dispersion. Furthermore, when the sample is embedded in a ring cavity, an ultranarrow transmission peak is obtained within the narrowed transparency windows. And by varying the tunneling, the linewidth and the position of the ultranarrow transmission peak can be engineered. Because no coupling laser is required, the scheme proposed here is more convenient for future experiments and applications in optics, and may be useful in designing novel optoelectronic devices. © 2014 Taylor & Francis. (56 refs.)Main Heading: Semiconductor quantum dotsControlled terms: Linewidth - Nanocrystals - Optoelectronic devices - Quantum interference devices - Quantum interference phenomena - Quantum optics - TransparencyUncontrolled terms: Electromagnetically induced transparency - Linewidth narrowing - Quantum interference - Transmission spectrums - Triple quantumClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 761 Nanotechnology - 931.3 Atomic and Molecular Physics

Database: Compendex

Low-timing-jitter mode-locked fiber laser based on graphene oxide PVA thin film as saturable absorber

Wu, Kan1; Li, Xiaohui2; Wang, Yonggang3; Wang, Qijie2; Shum, Perry Ping2; Chen, Jianping1 Source: Asia Communications and Photonics Conference, ACP, 2014

; ISSN: 2162108X; Conference: Asia Communications and Photonics Conference, ACP 2014, November 11, 2014 - November 14, 2014;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University, Shanghai, China2 Centre of Excellence for Photonics, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Ave., Singapore, Singapore3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We demonstrate a mode-locked fiber laser based on graphene oxide saturable absorber at 1550nm. The laser has a timing jitter of 53fs (100Hz to 100kHz). The contribution from the slow saturable absorber is also investigated. © 2014 OSA. (4 refs.)Main Heading: Mode-locked fiber lasersControlled terms: Fiber lasers - Graphene - Locks (fasteners) - Photonics - Saturable absorbers - Timing jitterUncontrolled terms: Graphene oxidesClassification Code: 601.3 Mechanisms - 712 Electronic and Thermionic Materials - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 744 Lasers - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

CFRP variable curvature mirror used for realizing non-moving-element optical zoom imaging

Zhao, Hui1; Fan, Xuewu1; Pang, Zhihai1; Ren, Guorui1; Wang, Wei1; Xie, Yongjie1; Ma, Zhen1; Du, Yunfei1; Su, Yu1; Wei, Jingxuan2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9293, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413786; DOI: 10.1117/12.2069856; Article number: 929307; Conference: International Optical Design Conference 2014, IODC 2014, June 23, 2014 - June 26, 2014; Sponsor: American Elements Corporation; Edmund Optics, Inc.; Optimax Systems, Inc.; Rochester Precision Optics, LLC; Synopsys, Inc.;

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, No.17 Xinxi Road, Xi'an, China2 School of Computer Science and Technology, No.2, South Taibai Road, Xi'an, China

Abstract: In recent years, how to eliminate moving elements while realizing optical zoom imaging has been paid much attention. Compared with the conventional optical zooming techniques, removing moving elements would bring in many benefits such as reduction in weight, volume and power cost and so on. The key to implement non-moving-element optical zooming lies in the design of variable curvature mirror (VCM). In order to obtain big enough optical magnification, the VCM should be capable of generating a large variation of saggitus. Hence, the mirror material should not be brittle, in other words the corresponding ultimate strength should be high enough to ensure that mirror surface would not be broken during large curvature variation. Besides that, the material should have a not too big Young's modulus because in this case less force is required to generate a deformation. Among all available materials, for instance SiC, Zerodur and et.al, CFRP (carbon fiber reinforced polymer) satisfies all these requirements and many related research have proven this. In this paper, a CFRP VCM is designed, fabricated and tested. With a diameter of 100mm, a thickness of 2mm and an initial curvature radius of 1740mm, this component could change its curvature radius from 1705mm to 1760mm, which correspond to a saggitus variation of nearly 23μm. The work reported further proves the suitability of CFRP in constructing variable curvature mirror which could generate a large variation of saggitus. © 2014 SPIE. (8 refs.)Main Heading: MirrorsControlled terms: Boundary integral equations - Carbon - Carbon fiber reinforced plastics - Design - Elastic moduli - Fiber reinforced materials - Fiber reinforced plastics - Optical design - Reinforced plastics - Reinforcement - Silicon carbide - Strength of materialsUncontrolled terms: Carbon fiber reinforced polymer - Curvature variation - Initial curvature - Mirror materials - Optical zoom - Saggitus variation - Ultimate strength - Variable curvature mirrorClassification Code: 408 Structural Design - 415 Metals, Plastics, Wood and Other Structural Materials - 415.2 Plastics Structural Materials - 421 Strength of Building Materials; Mechanical Properties - 422 Strength of Building Materials; Test Equipment and Methods - 531 Metallurgy and Metallography - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 804 Chemical Products Generally - 804.2 Inorganic Compounds - 811 Cellulose, Paper and Wood Products - 921.2 Calculus - 951 Materials Science

Database: Compendex

Research on the low light level image enhancement algorithm based on ICCD

Su, Yu1; Zhao, Hui1; Fan, Xuewu1; Feng, Liangjie1; Li, Ailing1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, December 1, 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.s210005; Article number: s210005;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: The key to realize low light level imaging lies in the use of intensified charge coupled device (ICCD) which has a sensitive respond to very low light environment. However, even with the ICCD, the bad lighting condition and very low level optical radiation can make the image quality have a big drop compared with the traditional imaging environment, which severely limits the application of low light level image. Therefore, to improve the quality of low light level image, the characteristics of low light level image are firstly analyzed and then a comprehensive image enhancement algorithm is proposed. The outdoor experiments have been designed and the results demonstrate the effectiveness of the proposed algorithms. It is worth noting that when the radiance level decreases to smaller than 0.7 lx, the algorithm is still effective. (11 refs.)Main Heading: AlgorithmsControlled terms: Charge coupled devices - Image enhancement - Image processing - Optical data processingUncontrolled terms: Image contrasts - Image enhancement algorithm - Intensified charge coupled devices - Lighting conditions - Low light level imaging - Low-light-level image - Optical radiations - Outdoor experimentClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921 Mathematics

Database: Compendex

A new subpixel imaging method for image super resolution

Wang, Jihong1; Zhou, Zuofeng1; Zhang, Jian1; Cao, Jianzhong1; Wu, Qingquan1; Fan, Xinming1; Gong, Zhendong1; Zhao, Bing1 Source: Proceedings - 2013 International Conference on Information Science and Cloud Computing, ISCC 2013, p 113-117, December 2, 2014; ISBN-13: 9781479949670; DOI: 10.1109/ISCC.2013.28; Article number: 6972570; Conference: 2013 International Conference on Information Science and Cloud Computing, ISCC 2013, December 7, 2013 - December 8, 2013;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, Shanxi Province, China

Abstract: The subpixel imaging technique for image super resolution can get a higher resolution image from two low resolution images which are observed from two linear array CCDs staggered half pixel both along the flight direction and perpendicular direction. In this paper, an adaptive weight interpolation method which considers the Euclidean distance information from two low resolution images for different size interpolation window is proposed. Compared with the traditional interpolation method, the experiment results show the effectiveness of the proposed method. (14 refs.)Main Heading: InterpolationControlled terms: Imaging techniques - Optical resolving powerUncontrolled terms: Euclidean distance - Higher resolution images - Image super resolutions - Interpolation method - Low resolution images - Sub pixels - Super resolution - Weighted interpolationClassification Code: 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 746 Imaging Techniques - 921.6 Numerical Methods

Database: Compendex

A test system for infrared focal plane arrays based on LabVIEW

Yaohong, Chen1; Wei, Liu1; Long, Ren1; Bo, Yi1; Qingsheng, Xie1; Zefeng, Wang1 Source: Proceedings - 2014 4th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2014, p 974-977, December 22, 2014; ISBN-13: 9781479965755; DOI: 10.1109/IMCCC.2014.205; Article number: 6995175; Conference: 4th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2014, September 18, 2014 - September 20, 2014;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: Most existing test system for infrared focal plane arrays are dedicated, it costly and the application value are limited. A test method for infrared focal plane arrays is introduced in this paper, and test system includes driving circuit, control module, data acquiring and processing circuit, video synthesis module and the PC software based on LabVIEW is established, which measures the key parameters such as responsivity, NETD, non-effective pixels and nonhomogeneity of the conventional polysilicon uncooled infrared focal plane arrays, generate testing report automatically at last. The simple and reliable test system adapted to many devices with different resolution and package, possess excellent universal property and practical value at very low cost. © 2014 IEEE. (7 refs.)Main Heading: Control system synthesisControlled terms: Computer programming languages - Data handling - Focal plane arrays - Focusing - Infrared detectors - Software testing - Testing - Video signal processingUncontrolled terms: Different resolutions - Infrared focal plane arrays - LabViEW - NETD - Processing circuits - Test systems - Uncooled infrared focal plane arrays - Universal propertiesClassification Code: 423.2 Non Mechanical Properties of Building Materials: Test Methods - 711.1 Electromagnetic Waves in Different Media - 716.4 Television Systems and Equipment - 723 Computer Software, Data Handling and Applications - 731.1 Control Systems - 741.3 Optical Devices and Systems - 941.4 Optical Variables Measurements

Database: Compendex

Efficient optical Kerr gating property of fluorotellurite glass

Xiong, Yaobing1; Yan, Lihe1; Zhou, Zhiguang2; Yi, Wenhui1; Lin, Aoxiang2; Si, Jinhai1; Chen, Feng1; Hou, Xun1 Source: Optik, v 125, n 3, p 1444-1447, 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.09.016;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Key Laboratory for Physical Electronics and Devices, Ministry of Education, Xi'An Jiaotong University, Xi'an, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an, China

Abstract: We investigated the ultrafast optical Kerr effect of the fluorotellurite glass (Ft glass), the nonlinear response time of which was measured to be less than 230 fs, while the nonlinear refractive index was estimated to be 9.62 × 10-16 cm2/W. Using optical Kerr gate (OKG) technique with Ft glass as Kerr medium, we obtained narrow-bandwidth and symmetric gated spectra from a supercontinuum (SC) generated by a femtosecond laser. Experimental results indicated that Ft glass was a good candidate for an OKG medium due to its fast response time, large nonlinearity, and high transparency. © 2013 Elsevier GmbH. All rights reserved. (21 refs.)Main Heading: Optical Kerr effectControlled terms: Glass - Nonlinear optics - Refractive indexUncontrolled terms: Fast response time - Fluoro-tellurite glass - High transparency - Nonlinear refractive index - Nonlinear response time - Optical Kerr gate - Super continuum - Ultrafast optical Kerr effectsClassification Code: 741.1 Light/Optics - 741.1.1 Nonlinear Optics - 812.3 Glass

Database: Compendex

Research on shared anode used for the large area array MCP detector

Song, Juan1, 2; Zhao, Bao-Sheng1; Sheng, Li-Zhi1; Liu, Zhe1; Dai, Jin-Fei1, 2; Liu, Yong-An1; Zhou, Yan-Nan1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 8, August 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144308.0823002; Article number: 0823002;

Abstract: The development of signal acquisition system used for the large area array of microchannel plate detector is very difficult. Multi-channel shared anode was put forward to solve this technical issue. Dual-channel shared anode and four-channel shared anode were designed. According to the basic standard that multi-channel Shared anode instead of single channel anode, signal transmission characteristics and collection efficiency were tested. Simulation experiment results show that signal transmission in multi-channel shared anode without attenuation and distortion, and the experimental results and simulation results are identical with each other; dual-channel shared anode's total count rate and four-channel shared anode's count rate are approximately equal to the sum of single channel anode count rate, the relative error of the count rate are 5.2%, 7.4% respectively. Four-channel shared anode can replace single channel anode and dual-channel shared anode, and the number of channels about electronics acquisition system is reduced to 1/4 of the original. So, the volume, weight and power of the whole acquisition system are reduced effectively. (12 refs.)Main Heading: ElectrodesControlled terms: Image storage tubes - Mergers and acquisitions - Microchannels - Particle beams - Signal processingUncontrolled terms: Acquisition systems - Collection efficiency - Count rates - Large area arrays - Microchannel plate detector - Signal acquisitions - Signal transmission - Single photon detectionClassification Code: 604 Metal Cutting and Machining - 631 Fluid Flow - 714.1 Electron Tubes - 716.1 Information Theory and Signal Processing - 912 Industrial Engineering and Management - 932.1 High Energy Physics

Database: Compendex

The design of reflective scanning device for drilling the inverted cone micro-hole with femtosecond laser pulses

Zhao, Hua-Long1; Zhou, Ren-Kui1; Zhao, Wei1; Yang, Xiao-Jun1; Li, Ming1; Jia, Hai-Ni1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 9, September 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144309.0914006; Article number: 0914006;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China

Abstract: Based on the Dove Prism scanning principle, a reflective scanning device was designed which was driven by high speed rotating motor and composed of three reflectors in K glyph configuration. The scanning device can be used for the femtosecond laser high-precision spiral drilling system and the accuracy is insensitive to the laser beam quality. The drilling scanning speed is twice as the motor speed with high drilling efficiency. Compared with Dove Prism System, the scanning device is easy to assemble and can avoid the pulse width broadening phenomenon of femtosecond laser. The tests show that it can accomplish high effective drilling the inverted cone micro holes whose diameters are between 0.05 mm and 0.2 mm with the machining accuracy less than ±2 μm. (12 refs.)Main Heading: Ultrashort pulsesControlled terms: Drilling - Drilling equipment - Laser beam machining - Machining - Microfabrication - Nozzles - Prisms - Profilometry - Scanning - Ultrafast lasersUncontrolled terms: Dove prism - Drilling efficiency - Drilling systems - High-precision - High-speed rotating - Machining Accuracy - Scanning device - Scanning speedClassification Code: 604 Metal Cutting and Machining - 604.2 Machining Operations - 631.1 Fluid Flow, General - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 943.3 Special Purpose Instruments

Database: Compendex

Ytterbium-doped large-mode-area silica fiber fabricated by using chelate precursor doping technique

Shi, Tengfei1, 2; Zhou, Zhiguang1; Ni, Li1; Xiao, Xusheng1, 2; Zhan, Huan1, 2; Zhang, Aidong1; Lin, Aoxiang1 Source: Applied Optics, n 15, p 3191-3195, May 20, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.003191;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an, China2 Graduate School of Chinese Academy of Sciences (CAS), Beijing, China

Abstract: We reported on a highly effective chelate precursor doping technique for Yb-doped large-mode-area (LMA) fiber manufacture. By accurately controlling the evaporation temperature and flow rate of carrier gas, the chelate precursor doping technique is capable of making Yb-doped LMA silica fiber with good uniformity free of center dip, low numerical aperture of &sim;0.056, large preform core size of 4.46 mm, and appropriate cladding absorption of 1.17 dB/m at 976.4 nm. Based on a single-end-pump all-fiber oscillator laser setup, the laser output at 1080 nm reached 700 W with slope efficiency of 54.2%. © 2014 Optical Society of America. (25 refs.)Main Heading: FibersControlled terms: Chelation - Pumping (laser) - Silica - YtterbiumUncontrolled terms: Chelate precursor - Doping techniques - Evaporation temperature - Large mode area - Large mode area fiber - Numerical aperture - Slope efficiencies - Ytterbium-dopedClassification Code: 547.2 Rare Earth Metals - 744.1 Lasers, General - 802.2 Chemical Reactions - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications

Database: Compendex

An effective fusion based on compressive sensing

Mou, Jiao1, 2; Gao, Wei1; Song, Zongxi1; Xi, Jiangbo1, 2; Wei, Laixing1, 2 Source: Journal of Information and Computational Science, v 11, n 11, p 3949-3958, July 20, 2014

; ISSN: 15487741; DOI: 10.12733/jics20104178;

Publisher: Binary Information PressAuthor affiliation: 1 Space Optics Laboratory, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: Based on Compressive Sensing (CS) theory, an effective fusion method with the advantages of low sampling rate, simple structure and easy implementation is presented in this paper. We take single layer wavelet decomposition for two source images to obtain a low-frequency sub-band and three highfrequency sub-bands. The sparse matrix gotten by sparse representation of the high-frequency coefficients with the random matrix is only measured, then the low-frequency coefficients and the measurements of the high-frequency sparse matrix are fused with different schemes. After these process, high-frequency coefficients from the fused measurements is reconstructed via the Orthogonal Matching Pursuit (OMP) algorithm, and the fused image is obtained by inverse wavelet transform. Experimental results show, at the same sampling rates, the proposed method exhibits its superiority over the fusion method based on the Maximum of Absolute Values (MAV), self-adaptive weighted average fusion schemes based on entropy and standard deviation respectively, and under the lower sampling rate, it can also achieve better fusion performance. ©2014 Binary Information Press (12 refs.)Main Heading: Compressed sensingControlled terms: Image fusion - Image matching - Matrix algebra - Signal reconstruction - Wavelet decompositionUncontrolled terms: Compressive sensing - Fusion performance - Inverse wavelet transforms - Orthogonal matching pursuit - Random observations - Sparse representation - Standard deviation - Weighted averagesClassification Code: 716.1 Information Theory and Signal Processing - 723.2 Data Processing and Image Processing - 921.1 Algebra - 921.3 Mathematical Transformations

Database: Compendex

Optical system design of near infrared spectroscopy based on polarized interference

Xie, Zheng-Mao1, 2; Gao, Li-Min1; He, Jun-Hua1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 12, December 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144312.1222003; Article number: 1222003;

Abstract: Based on polarized interference principle, an optical system of near infrared spectroscopy with single optical path was proposed. For the tungsten halogen source coupled with optical fiber, the collimated and convergent systems using 90° off-axial parabolic mirror were designed. He-ne laser as source for sampling control was introduced, and the beams are combined and split with near infrared by a cold mirror. Two perpendicular Glan-thompson prisms are introduced as polarizers, within the compensated crystal and scanning wedge are set as optical phase compensator of the polarization interference. A near infrared polarization interference-based optical system was designed, whose wavelength band is from 800 nm to 1700 nm, theoretical spectrum resolution is better than 8 cm-1, and clear aperture is Φ10.4 mm. The results of quality evaluation show that the root mean square radius at marginal field of view according to the spot diagram is about 1.7 μm, the lateral chromatic aberration is 0.2 μm, and the geometric encircled energy at all the field of view has reached to 100% within a diameter of Φ14 μm. (11 refs.)Main Heading: Optical systemsControlled terms: Aberrations - Adaptive optics - Fourier transforms - Infrared devices - Laser mirrors - Mirrors - Near infrared spectroscopy - Optical design - Optical fibers - Polarization - Quality control - SpectroscopyUncontrolled terms: Chromatic aberration - Convergent systems - Fourier transformations - Glan-Thompson prism - Near infrared spectra - Polarization interferences - Root mean square radius - Theoretical spectraClassification Code: 741 Light, Optics and Optical Devices - 801 Chemistry - 913.3 Quality Assurance and Control - 921.3 Mathematical Transformations

Database: Compendex

Standoff two-color quantum ghost imaging through turbulence

Xue, Yu-Lang1, 2; Wan, Ren-Gang1; Feng, Fei1, 2; Zhang, Tong-Yi1 Source: Applied Optics, n 14, p 3035-3042, May 10, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.003035;

Abstract: Recently, a two-color quantum ghost imaging configuration was proposed by Karmakar et al. [Phys. Rev. A 81, 033845 (2010)]. By illuminating an object located far away from the source and detector, with a signal beam of long wavelength to avoid absorptionofshort wavelengths in the atmosphere while a reference beam of short wavelength is detected locally, this imaging configuration can be appropriate for standoff sensing. In practice, the signal beam must propagate through atmosphere in the presence of serious turbulence. We analyzed theoretically the performance of this ghost imaging configuration through turbulence. Based on the Gaussian state source model and extended Huygens-Fresnel integral, a formula is derived to depict the ghost image formed through turbulence of a standoff reflective object. Numerical calculations are also given according to the formula. The results show that the image quality will be degraded by the turbulence, but the resolution can be improved by means of optimizing the wavelengths of the reference and signal beams even when the turbulence is very serious. © 2014 Optical Society of America. (32 refs.)Main Heading: Imaging techniquesControlled terms: Gaussian beams - Image processing - TurbulenceUncontrolled terms: Extended Huygens-Fresnel integrals - Imaging configurations - Long wavelength - Numerical calculation - Quantum ghost imaging - Reflective objects - Short wavelengths - Standoff sensingClassification Code: 443.1 Atmospheric Properties - 711 Electromagnetic Waves - 741 Light, Optics and Optical Devices - 746 Imaging Techniques

Database: Compendex

Cavity linewidth narrowing by tunneling induced double dark resonances in triple quantum dot molecules

Tian, Si-Cong1; Wan, Ren-Gang2; Li, Lian-He1; Tong, Cun-Zhu1; Ning, Yong-Qiang1 Source: Optics Communications, v 334, p 94-100, January 15, 2015

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.08.011;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, China2 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China

Abstract: A scheme for obtaining a tunable ultranarrow cavity transmission controlled by two tunneling in triple quantum dots system is proposed. In such system, the tunneling can induce double dark resonances, resulting in the appearance of two transparency windows. With the steep dispersion within the narrowed transparency windows, an ultranarrow transmission peak can be obtained, compared with that of double quantum dots system. Furthermore, by varying the energy splitting, the linewidth and the position of the ultranarrow transmission peak can be engineered. Because no coupling laser is required, the scheme proposed here is more convenient for future experiments and applications in optics, and may be useful in designing novel optoelectronic devices. © 2014 Elsevier B.V. (53 refs.)Main Heading: Semiconductor quantum dotsControlled terms: Linewidth - Optoelectronic devices - Quantum optics - TransparencyUncontrolled terms: Cavity linewidths - Double quantum dots - Electromagnetically induced transparency - Energy splittings - Linewidth narrowing - Transmission peaks - Transmission spectrums - Triple quantumClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 931.3 Atomic and Molecular Physics

Database: Compendex

An improved stereo match algorithm based on support-weight approach

Long, Ren1; Lei, Yang1; Xiao-Dong, Zhao1, 2; Zuo-Feng, Zhou1; Guang-Sen, Liu1; Fei, Jiaqi1 Source: Proceedings - 2014 4th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2014, p 964-967, December 22, 2014; ISBN-13: 9781479965755; DOI: 10.1109/IMCCC.2014.203; Article number: 6995173; Conference: 4th International Conference on Instrumentation and Measurement, Computer, Communication and Control, IMCCC 2014, September 18, 2014 - September 20, 2014;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian, China2 Graduate University, Chinese Academy of Sciences, Beijing, China

Abstract: Local stereo matching methods are still used widely because they are fast and simple. But the accuracy of local methods is much poorer than the global methods. They usually achieve accuracy at the expense of speed. Simple local methods are fast, but exhibit systematic errors. In this paper we propose an improved method based on support-weight approach, which can enhance the matching efficiency and accuracy. By utilizing a adaptive support-window which will change the size of the window relying on different area, we use a new disparity cost volume function which is much more simple than the traditional one. From the experimental result, we can see the accuracy of the disparity map is as better as the traditional one while the computational time is reduced. The proposed method includes three procedures, At first, we need to confirm the pixels 'window size in order to calculate the disparity, secondly, the adaptive support-weight of each pixel in left image will be calculated, the final step is to select the most optimal disparity in the right image. After the three steps, we can get the best matching point in the right image which is corresponding to the right image. © 2014 IEEE. (9 refs.)Main Heading: Image matchingControlled terms: Algorithms - Pixels - Stereo image processing - Stereo vision - Systematic errorsUncontrolled terms: Adaptive support - Adaptive support weights - Computational time - Local methods - Local stereo matching - Stereo matching - Support-weight approach - Volume functionsClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 741.2 Vision - 921 Mathematics - 922 Statistical Methods

Database: Compendex

Laser communication optical system based on reflective eccentric-pupil cassegrain antenna

Yan, Peipei1; Deng, Xiaoguo1; Zhang, Hengjin1; Mei, Chao1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, September 10, 2014

; ISSN: 02532239; DOI: 10.3788/AOS201434.s122003; Article number: s122003;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 The Photoelectric Measurement and Control Technology Research Department, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; Shaanxi, China

Abstract: The concept of reflective eccentric-pupil Cassegrain antenna is introduced. Because the traditional on-axis Cassegrain antenna used in laser communication has obscuration, the efficiency of transmitting and receiving power is decreased greatly. This new kind of reflective eccentric-pupil Cassegrain antenna is unobscured, so it improves the efficiency of transmitting power and receiving power effectively. Its properties such as gain, image quality, and transmission efficiency are analyzed. The power decline curve is obtained by detailed analyzing the antenna system in partial axis situation. Besides, it is transceiver, so the system volume and weight are reduced greatly. The complexity is reduced enormously at the same time. (10 refs.)Main Heading: Optical communicationControlled terms: Antennas - Efficiency - Optical links - Optical systemsUncontrolled terms: Antenna system - Cassegrain - Cassegrain antenna - Decline curves - Receiving gain - Receiving power - Transmission efficiency - Transmitting powerClassification Code: 716 Telecommunication; Radar, Radio and Television - 717.1 Optical Communication Systems - 741.3 Optical Devices and Systems - 913.1 Production Engineering

Database: Compendex

Reflective carbon nanotube as the saturable absorber for mode-locked 1064 nm laser

Fan, Mingwen1; Ma, Baomin2; Liu, Jie1; Wang, Yonggang3 Source: Optik, v 125, n 19, p 5666-5668, 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.07.051;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 College of Physics and Electronics, Shandong Normal University, Jinan, China2 School of Information Science and Engineering, Shandong University, Jinan, China3 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: With a reflective single-walled carbon nanotube as the saturable absorber, a laser diode-pumped passively mode-locked Nd:YVO<inf>4</inf> laser at 1064 nm was realized for the first time. The pulse duration of 12 ps was produced with a repetition rate of 83.7 MHz. The peak power and the single pulse energy of the mode-locking laser were 1.28 kW and 15.4 nJ, respectively. © 2014 Elsevier GmbH. All rights reserved. (20 refs.)Main Heading: Single-walled carbon nanotubes (SWCN)Controlled terms: Carbon - Laser mode locking - Locks (fasteners) - Mode-locked fiber lasers - Passive mode locking - Pulse repetition rate - Pumping (laser) - Q switched lasers - Saturable absorbers - YarnUncontrolled terms: 1064 nm lasers - Laser-diode-pumped - Mode-locked laser - Nd : YVO - Passively mode-locked - Pulse durations - Repetition rate - Single pulse energyClassification Code: 601.3 Mechanisms - 744.1 Lasers, General - 761 Nanotechnology - 804 Chemical Products Generally - 819.4 Fiber Products

Database: Compendex

Research on color constancy computation based on YCbCr color space and gray surface

Wang, Hong1, 2; Yang, Jianfeng1; Xue, Bin1; Yan, Xingtao1; Liang, Xiaofen1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9301, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413878; DOI: 10.1117/12.2070658; Article number: 93010V; Conference: International Symposium on Optoelectronic Technology and Application 2014: Image Processing and Pattern Recognition, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: Color constancy is of important for many computer vision applications, such as image classification, color object recognition, object tracking and so on. But unlike the human visual system, imaging device cannot be able to compute color constant descriptors which do not vary with the color of the illuminant, so solving color constancy problem is necessary. In the calculation of color constancy, illuminant estimation is the key. Because grey surfaces can perfectly reflect the color of the scene illumination, many methods have been proposed to identify grey surfaces to estimate the illuminant. But they either rely on the camera.s parameters, lacking universality, or work inaccurate in worse conditions. In order to solve these problems, in this paper, an iterative method is proposed. The quality of the proposed method is tested and compared to the previous color constancy methods on the Macbeth Chart and two data sets of synthetic and real images. Through MATLAB simulation, experimental pictures and quantitative data for performance evaluation were gotten. The simulated results show that the proposed algorithm is accurate and efficient in identification of the grey surfaces, even in worse condition. And it performs well in color constancy computation on both synthetic and real images. © 2014 SPIE. (13 refs.)Main Heading: ColorControlled terms: Color computer graphics - Color image processing - Computer vision - Image classification - Image processing - Iterative methods - MATLAB - Object recognition - Pattern recognitionUncontrolled terms: Color constancy - Color object recognition - Computer vision applications - Grey surfaces - Human Visual System - Illuminant estimation - Illumination estimation - Ycbcr color spacesClassification Code: 716 Telecommunication; Radar, Radio and Television - 723.5 Computer Applications - 741 Light, Optics and Optical Devices - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

A novel real-time method for high dynamic range image tone mapping

Wu, Qingquan1; Zhou, Zuofeng1; Leng, Hanbing1; Cao, Jianzhong1; Wang, Jihong1; Gong, Zhendong1; Fan, Xinming1; Guo, Huinan1 Source: ICIST 2014 - Proceedings of 2014 4th IEEE International Conference on Information Science and Technology, p 433-436, October 10, 2014; ISBN-13: 9781479948086; DOI: 10.1109/ICIST.2014.6920510; Article number: 6920510; Conference: 2014 4th IEEE International Conference on Information Science and Technology, ICIST 2014, April 26, 2014 - April 28, 2014; Sponsor: Chinese Academy of Engineering; IEEE Beijing Section; The Chinese University of Hong Kong;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, CAS, Xi'an, Shaanxi Province, China

Abstract: Tone-mapping technique which can convert high dynamic range (HDR) to low dynamic range (LDR) images provides accurately visualization of HDR images on standard LDR displays. Most of the existing tone-mapping method could not realize real time processing while preserving good visualization. Utilizing an adaptive three-section lookup table, this paper proposes an effective, high quality, real time technique to convert 12-bit images to 8-bit image which can preserve abundant details and high contrast simultaneously. Experiment results show that this method can improve the weak signals of the image greatly, and the low luminance details can be observed distinctly on an 8-bit monitor. © 2014 IEEE. (16 refs.)Main Heading: MappingControlled terms: Table lookup - VisualizationUncontrolled terms: component HDRimage - Real time - Three-section - TMQI - Tone mappingClassification Code: 723.1 Computer Programming - 902.1 Engineering Graphics

Database: Compendex

High-efficiency Terahertz-wave generation in silicon membrane waveguides

Liu, Hongjun1; Wang, Zhaolu1; Huang, Nan1; Sun, Qibing1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9199, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628412260; DOI: 10.1117/12.2060232; Article number: 91990D; Conference: Terahertz Emitters, Receivers, and Applications V, August 17, 2014 - August 18, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, China

Abstract: Terahertz (THz) wave generation via four-wave mixing (FWM) in silicon membrane waveguides is investigated with mid-infrared pump. The silicon membrane waveguides with width of 12 μm and heights varied from 14 μm to 17 μm, which can confine the THz-wave ranging from 7.5 THz to 10 THz due to the large refractive index contrast of the waveguide core and cladding, are designed to realize the collinear phase matching for THz-wave generation via FWM. Compared with the conventional parametric amplification or wavelength conversion based on FWM in silicon waveguides, which needs a pump wavelength located in the anomalous group-velocity dispersion (GVD) regime to realize broad phase matching, the pump wavelength located in the normal GVD regime is required to realize phase matching because of the large signal-pump frequency detuning. Phase matching for a tunable THz-wave ranging from 8.57 THz to 10 THz can be realized by tuning the pump wavelength from 4.2 μm to 4.4 μm in the silicon waveguide with rib height of 15 μm. Whilst, the phase matching bandwidth of THz-wave ranging from 7.7 THz to 10 THz can be achieved by tailoring the waveguide height from 14 μm to 17 μm when the pump wavelength is 4.3μm. Moreover, the conversion efficiency of the THz-wave generation is studied with different pump wavelengths and waveguide heights, the maximum conversion efficiency of 1.25 % at 9.2 THz can be obtained in a 6-mm long silicon waveguide when the pump wavelength is 4.3 μm and the waveguide height is 15 μm. © 2014 SPIE. (16 refs.)Main Heading: Terahertz wavesControlled terms: Conversion efficiency - Dispersions - Efficiency - Four wave mixing - Group velocity dispersion - Phase matching - Refractive index - Silicon - WaveguidesUncontrolled terms: High-efficiency - Parametric amplification - Phase-matching bandwidth - Pump wavelength - Silicon membranes - Silicon waveguide - Terahertz wave generation - Waveguide coreClassification Code: 525.5 Energy Conversion Issues - 711 Electromagnetic Waves - 712.1.1 Single Element Semiconducting Materials - 713 Electronic Circuits - 714.3 Waveguides - 741.1 Light/Optics - 913.1 Production Engineering - 951 Materials Science

Database: Compendex

Multifunction medical endoscope system with optical fiber temperature sensor

He, Zhengquan1; Zhou, Libin2; Luo, Baoke1; Hu, Baowen1; Du, Xinchao1; Li, Yulin1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9216, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628412437; DOI: 10.1117/12.2074540; Article number: 921606; Conference: 8th Conference of Optics and Photonics for Information Processing, August 18, 2014 - August 20, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, No.17 Xinxi Road, New Industrial Park, Xi'an Shaanxi Province, China2 Department of Physics, Northwest University, No. 229 Taibaibei Road, Xi'an Shaanxi Province, China

Abstract: Thermal therapy (or hyperthermia) is one of the effective operations for tumor treating and curing. As tumor tissues are more susceptible to heat than normal tissues, in thermal therapy operations, temperature on operation area is a crucial parameter for optimal treating. When the temperature is too low, the tumor tissues cannot be killed; otherwise, the temperature is too high, the operation may damage normal tissues around the tumor. During thermal therapy operation, the heating power is normally supplied by high-frequency EM field, so traditional temperature sensors, such as thermal couples, thermistors, cannot work stably due to EM interference. We present a multi-function endoscope optical fiber temperature sensor system. With this sensor setup based on principle of fluorescence life time, the temperature on operation point is detected in real time. Furthermore, a build-in endoscope centers in the fiber sensor, thus the operation area can be viewed or imaged directly during the operation. This design can navigate the operation, particularly for in vivo operations. The temperature range of the sensor system is 30°C-150°C, the accuracy can achieve to 0.2°C. The imaging fiber buddle is constituted of more than 50k fibers. As the sensor probe is very thin (around 4 mm in diameter), it can also be assembled inside the radiofrequency operation knife. With the presented sensor system in clinic operation physicians can check the temperature in the operation point and view the operation area at the same time. © 2014 SPIE. (14 refs.)Main Heading: TissueControlled terms: Endoscopy - Fibers - Fluorescence - Histology - Hyperthermia therapy - Information science - Optical fibers - Optical sensors - Photonics - Temperature sensors - TumorsUncontrolled terms: Crucial parameters - Fiber temperature sensors - Fiber-optical sensors - Fluorescence lifetimes - Medical endoscopes - Radio frequencies - Temperature range - Thermal therapiesClassification Code: 461.2 Biological Materials and Tissue Engineering - 461.6 Medicine and Pharmacology - 732 Control Devices - 741.1 Light/Optics - 741.1.2 Fiber Optics - 801 Chemistry - 812 Ceramics, Refractories and Glass - 817 Plastics and Other Polymers: Products and Applications - 903 Information Science

Database: Compendex

Wide-bandwidth zero-dispersion slow light in MKRs with a two-ring parallel connection structure based on an analogue of electromagnetically induced transparency

Xu, Yiping1, 2; Ren, Liyong1; Ma, Chengju1, 2; Wang, Yingli1; Liang, Jian1; Qu, Enshi1 Source: Journal of Modern Optics, v 61, n 13, p 1109-1114, July 29, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.922629;

Abstract: Based on an analog of electromagnetically induced transparency (EIT) in microfiber knot resonators with a two-ring parallel connection structure, a wide bandwidth and zero-dispersion slow-light waveguide is proposed. The EIT-like transmission spectrum with the variation of wavelengths for different coupling coefficients is numerical simulated. By appropriately adjusting the coupling coefficients of the two knot rings, a group time delay of about 72.4 ps with a flat wavelength bandwidth of about 82.7 pm and a full width at half-maximum of about 228 pm at one of the induced transparency windows is achieved theoretically. And the group time delay dispersion at the same induced transparency window nearly reaches to zero with a wavelength bandwidth of about 82.7 pm. © 2014 Taylor & Francis. (47 refs.)Main Heading: Dispersion (waves)Controlled terms: Bandwidth - Dispersions - Electric connectors - Group delay - Quantum optics - Resonators - Slow light - TransparencyUncontrolled terms: Coupling coefficient - Electromagnetically induced transparency - Group delay dispersion - Induced transparency - Micro-fiber - Micro-fiber knot resonators - Parallel connections - Transmission spectrumsClassification Code: 703.1 Electric Networks - 706.2 Electric Power Lines and Equipment - 711.1 Electromagnetic Waves in Different Media - 714 Electronic Components and Tubes - 716.1 Information Theory and Signal Processing - 741.1 Light/Optics - 951 Materials Science

Database: Compendex

Color fusion method for low-level light and infrared images

Yang, Shaokui1, 2; Liu, Wen1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 5, p 1654-1659, May 2014; Language: Chinese

; ISSN: 10072276;

Abstract: The complementary nature of low-level light image intensifiers and thermal infrared cameras makes them possible to observe the scene under almost any conditions (day/night/smoke/fog). A color fusion method of low-level-light and infrared images was introduced to render multiband imagery in comparative realistic color appearance. Firstly, the center-surround opponent-color fusion scheme was used to yield color imagery. Next, the histograms of the image were matched to those of the reference image in YCbCr color space. This transfered the natural color characteristics of daylight imagery into multispectral night vision images. In order to enhance the contrast of the fused imagery, a grayscale fused image was used to replace the luminance component of the multiband imagery and then implement the histogram matching. The experiment results demonstrate the proposed method is effective in displaying the fused imagery in natural colors and popping out targets. This fused data can help observers or machine vision systems to process this type of images efficiently, therefore reducing detection and recognition times and improving situational awareness. (10 refs.)Main Heading: Color matchingControlled terms: Color - Computer vision - Graphic methods - Infrared imaging - Infrared radiation - Statistical methodsUncontrolled terms: Color transfers - Histogram matching - Luminance component - Machine vision systems - Night vision images - Opponent colors - Situational awareness - Thermal infrared camerasClassification Code: 741.1 Light/Optics - 741.2 Vision - 746 Imaging Techniques - 801 Chemistry - 803 Chemical Agents and Basic Industrial Chemicals - 902.1 Engineering Graphics - 922.2 Mathematical Statistics

Database: Compendex

Investigation on wavelength multicasting technology based on XPM in a highly nonlinear fiber

Wang, Minjie1, 2, 3; Zhang, Jian-Guo4 Source: Journal of Modern Optics, v 61, n 13, p 1039-1046, July 29, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.922631;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 College of Sciences, Henan Agricultural University, Zhengzhou, China4 Department of Engineering and Design, London South Bank University, London, United Kingdom

Abstract: All-optical wavelength conversion with multicasting is investigated in this paper, which is based on cross-phase modulation in a highly nonlinear fiber. With a pump-modulated light and only a single continuous-wave probe, wavelength multicasting is realized by appropriately controlling the powers of two beams. Our simulation work reveals that 10 multicast channels can be obtained with their Q factors being larger than six, if both pump and probe powers are properly selected. These wavelength channels of multicasting are positioned around the central wavelength of the probe on the blue-shifted and red-shifted sides. The central wavelength and the channel spacing can be affected by the wavelengths of the probe and the pump. The wavelength multicasting technique studied in this paper is simpler and can offer more multicast channels than that based on four-wave mixing. © 2014 Taylor & Francis. (15 refs.)Main Heading: MulticastingControlled terms: Nonlinear optics - Phase modulation - Probes - Pumps - WavelengthUncontrolled terms: All-optical wavelength conversion - Central wavelength - Cross-phase modulations - Highly nonlinear fibers - Multicast channels - Technology-based - Wavelength channels - Wavelength multicastingClassification Code: 618.2 Pumps - 711 Electromagnetic Waves - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741.1.1 Nonlinear Optics - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Feature learning for image classification via multiobjective genetic programming

Shao, Ling1, 2; Liu, Li2; Li, Xuelong3 Source: IEEE Transactions on Neural Networks and Learning Systems, v 25, n 7, p 1359-1371, July 2014

; ISSN: 2162237X, E-ISSN: 21622388; DOI: 10.1109/TNNLS.2013.2293418; Article number: 6683022;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, S1 3JD, United Kingdom3 Center for OPTical IMagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Feature extraction is the first and most critical step in image classification. Most existing image classification methods use hand-crafted features, which are not adaptive for different image domains. In this paper, we develop an evolutionary learning methodology to automatically generate domain-adaptive global feature descriptors for image classification using multiobjective genetic programming (MOGP). In our architecture, a set of primitive 2-D operators are randomly combined to construct feature descriptors through the MOGP evolving and then evaluated by two objective fitness criteria, i.e., the classification error and the tree complexity. After the entire evolution procedure finishes, the best-so-far solution selected by the MOGP is regarded as the (near-)optimal feature descriptor obtained. To evaluate its performance, the proposed approach is systematically tested on the Caltech-101, the MIT urban and nature scene, the CMU PIE, and Jochen Triesch Static Hand Posture II data sets, respectively. Experimental results verify that our method significantly outperforms many state-of-the-art hand-designed features and two feature learning techniques in terms of classification accuracy. © 2013 IEEE. (46 refs.)Main Heading: Image classificationControlled terms: Feature extraction - Genetic algorithms - Genetic programming - Multiobjective optimizationUncontrolled terms: Classification accuracy - Classification errors - Classification methods - Evolutionary Learning - Feature descriptors - Feature learning - Multiobjective genetic programming - Tree complexityClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 723.1 Computer Programming - 921 Mathematics - 921.5 Optimization Techniques

Database: Compendex

A probabilistic associative model for segmenting weakly supervised images

Zhang, Luming1; Yang, Yi2; Gao, Yue3; Yu, Yi1; Wang, Changbo4; Li, Xuelong5 Source: IEEE Transactions on Image Processing, v 23, n 9, p 4150-4159, September 2014

; ISSN: 10577149; DOI: 10.1109/TIP.2014.2344433; Article number: 6868266Author affiliation: 1 School of Computing, National University of Singapore, Singapore, 119077, Singapore2 School of Information Technology and Electrical Engineering, University of Queensland, Brisbane, QLD, 4072, Australia3 Department of AutomationTsinghua, National Laboratory for Information Science and Technology, Tsinghua University, Beijing, 100084, China4 East China Normal University, Shanghai, 200241, China5 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi, 710119, China

Abstract: Weakly supervised image segmentation is an important yet challenging task in image processing and pattern recognition fields. It is defined as: in the training stage, semantic labels are only at the image-level, without regard to their specific object/scene location within the image. Given a test image, the goal is to predict the semantics of every pixel/superpixel. In this paper, we propose a new weakly supervised image segmentation model, focusing on learning the semantic associations between superpixel sets (graphlets in this paper). In particular, we first extract graphlets from each image, where a graphlet is a small-sized graph measures the potential of multiple spatially neighboring superpixels (i.e., the probability of these superpixels sharing a common semantic label, such as the sky or the sea). To compare different-sized graphlets and to incorporate image-level labels, a manifold embedding algorithm is designed to transform all graphlets into equal-length feature vectors. Finally, we present a hierarchical Bayesian network to capture the semantic associations between postembedding graphlets, based on which the semantics of each superpixel is inferred accordingly. Experimental results demonstrate that: 1) our approach performs competitively compared with the state-of-the-art approaches on three public data sets and 2) considerable performance enhancement is achieved when using our approach on segmentation-based photo cropping and image categorization. © 2014 IEEE. (42 refs.)Main Heading: SemanticsControlled terms: Association reactions - Bayesian networks - Image segmentation - Pattern recognitionUncontrolled terms: Embedding algorithms - Hierarchical Bayesian networks - Image segmentation model - Performance enhancements - Probabilistic modeling - Semantic associations - State-of-the-art approach - Weakly-supervisedClassification Code: 716 Telecommunication; Radar, Radio and Television - 741.1 Light/Optics - 802.2 Chemical Reactions - 903.2 Information Dissemination - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Transmission-type plano-concave lens using in the range of extreme ultraviolet wavelength

Li, Yan1; Xu, Xiangyan2; Li, Xiao-Li1 Source: IEEE Photonics Technology Letters, v 26, n 12, p 1239-1242, June 15, 2014

; ISSN: 10411135; DOI: 10.1109/LPT.2014.2320551; Article number: 6807675;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Science, Xi'an Shiyou University, Xi'an 710065, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: A one-dimensional photonic crystal consisting of the fourth-order Fibonacci multilayer films has been studied by the finite-difference time-domain method and transfer matrix method. The refractive indices for two layers of the Fibonacci multilayer films are similar with that of manganese and silicon in the extreme ultraviolet (EUV) band. The simulation result shows that there is an isotropic negative refractive index for the one-dimensional photonic crystal. Based on the character above, a kind of transmission-type plano-concave lens, which can be used in the EUV band (or soft X-ray), is designed. The distributions of the electromagnetic field for the lens and transimissivity of the Fibonacci multilayers films have also been calculated. The result demonstrates that the lens can focus the incoming EUV radiation, and its transmissivity is bigger than 5%-9% compared with that of the Fibonacci multilayers films, having the same structure with the lens. This letter has potential applications in the tansmission-type lens for EUV lithography. © 2014 IEEE. (11 refs.)Main Heading: Refractive indexControlled terms: Electromagnetic fields - Extreme ultraviolet lithography - Finite difference time domain method - Multilayer films - Multilayers - Photonic crystals - Transfer matrix methodUncontrolled terms: EUV radiation - Extreme Ultraviolet - Extreme ultraviolets - Fibonacci multilayers - Finite-difference time-domain (FDTD) methods - Negative refractive index - One dimensional photonic crystal - TransmissivityClassification Code: 701 Electricity and Magnetism - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 813.2 Coating Materials - 921 Mathematics - 933.1 Crystalline Solids

Database: Compendex

GA-SIFT: A new scale invariant feature transform for multispectral image using geometric algebra

Li, Yanshan1; Liu, Weiming2; Li, Xiaotang3; Huang, Qinghua4; Li, Xuelong5 Source: Information Sciences, v 281, p 559-572, October 10, 2014

; ISSN: 00200255; DOI: 10.1016/j.ins.2013.12.022;

Publisher: Elsevier Inc.Author affiliation: 1 Shenzhen University, Shenzhen 518060, China2 School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China3 Harbin University of Commerce, Harbin, China4 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China5 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Feature analysis plays an important role in many multispectral image applications and scale invariant feature transform (SIFT) has been successfully applied for extraction of image features. However, the existing SIFT algorithms cannot extract features from multispectral images directly. This paper puts forward a novel algorithmic framework based on the SIFT for multispectral images. Firstly, with the theory of the geometric algebra (GA), a new representation of multispectral image including spatial and spectral information is put forward and discussed. Secondly, a new method for obtaining the scale space of the multispectral image is proposed. Thirdly, following the procedures of the SIFT, the GA based difference of Gaussian images are computed and the keypoints can be detected in the GA space. Fourthly, the feature points are finally detected and described in the mathematical framework of the GA. Finally, the comparison results show that the GA-SIFT outperforms some previously reported SIFT algorithms in the feature extraction from a multispectral image, and it is comparable with its counterparts in the feature extraction of color images, indicating good performance in various applications of image analysis. © 2014 Elsevier Inc. All rights reserved. (48 refs.)Main Heading: Image processingControlled terms: Feature extraction - Genetic algorithmsUncontrolled terms: Algorithmic framework - Comparison result - Geometric Algebra - Mathematical frameworks - Multispectral images - Scale invariant feature transforms - SIFT - Spectral informationClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Simultaneous picosecond and femtosecond solitons delivered from a nanotube-mode-locked all-fiber laser

Han, D.D.1; Liu, X.M.1; Cui, Y.D.1; Wang, G.X.1; Zeng, C.1; Yun, L.1 Source: Optics Letters, v 39, n 6, p 1565-1568, March 15, 2014

; ISSN: 01469592, E-ISSN: 15394794; DOI: 10.1364/OL.39.001565;

Abstract: We propose a compact nanotube-mode-locked all-fiber laser that can simultaneously generate picosecond and femtosecond solitons at different wavelengths. The pulse durations of picosecond and femtosecond solitons are measured to be &tilde;10.6 ps and &tilde;466 fs, respectively. Numerical results agree well with the experimental observations and clearly reveal that the dynamic evolutions of the picosecond and femtosecond solitons are qualitatively distinct in the intracavity. Our study presents a simple, stable, low-cost, and dual-scale ultrafast-pulsed laser source suitable for practical applications in optical communications. © 2014 Optical Society of America. (42 refs.)Main Heading: SolitonsControlled terms: Fiber lasers - Locks (fasteners) - Mode-locked fiber lasers - Nanotubes - Optical communicationUncontrolled terms: All-fiber lasers - Dynamic evolution - Femtoseconds - Intracavities - Laser sources - Numerical results - Picoseconds - Pulse durationsClassification Code: 601.3 Mechanisms - 717.1 Optical Communication Systems - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 931.3 Atomic and Molecular Physics

Database: Compendex

NATAS: Neural activity trace aware saliency

Zhu, Guokang1; Wang, Qi1; Yuan, Yuan1 Source: IEEE Transactions on Cybernetics, v 44, n 7, p 1014-1024, July 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2279002; Article number: 6680765;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Center for Optical Imagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Saliency detection has raised much interest in computer vision recently. Many visual saliency models have been developed for individual images, video clips, and image pairs. However, image sequence, one most general occasion in the real world, is not explored yet. A general image sequence is different from video clips whose temporal continuity is maintained and image pairs where common objects exist. It might contain some similar low-level properties while completely distinct contents. Traditional saliency detection methods will fail on these general sequences. Based on this consideration, this paper investigates the shortcomings of the classical saliency detection methods, which significantly limit their advantages: 1) inability to capture the natural connections among sequential images, 2) over-reliance on motion cues, and 3) restriction to image pairs/videos with common objects. In order to address these problems, we propose a framework that performs the following contributions: 1) construct an image data set as benchmark through a rigorously designed behavioral experiment, 2) propose a neural activity trace aware saliency model to capture the general connections among images, and 3) design a novel measure to handle the low-level clues contained among sequential images. Experimental results demonstrate that the proposed saliency model is associated with a tremendous advancement compared with traditional methods when dealing with the general image sequence. © 2013 IEEE. (49 refs.)Main Heading: Behavioral researchControlled terms: Artificial intelligence - Brain - Computer vision - Learning systems - Neurons - Video camerasUncontrolled terms: Global contrasts - Neural activity - preactivation - Saliency detection - Visual AttentionClassification Code: 461.1 Biomedical Engineering - 461.9 Biology - 723.4 Artificial Intelligence - 723.5 Computer Applications - 742.2 Photographic Equipment - 971 Social Sciences

Database: Compendex

Interactive segmentation using constrained laplacian optimization

Shen, Jianbing1; Du, Yunfan1; Li, Xuelong2 Source: IEEE Transactions on Circuits and Systems for Video Technology, v 24, n 7, p 1088-1100, July 2014

; ISSN: 10518215; DOI: 10.1109/TCSVT.2014.2302545; Article number: 6727434;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Beijing Key Laboratory of Intelligent Information Technology, School of Computer Science, Beijing Institute of Technology, Beijing 100081, China2 State Key Laboratory of Transient Optics and Photonics, Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: We present a novel interactive image segmentation approach with user scribbles using constrained Laplacian graph optimization. A novel energy framework is developed by adding the smoothing item in the cost function of Laplacian graph energy. To the best of our knowledge, our approach is the first to incorporate the normalized cuts and graph cuts algorithms into a unified energy optimization framework. The proposed approach is further accelerated by running the proposed optimization method on a band region when we segment the large images. Our acceleration strategy enables our approach to efficiently segment the large images, which yields about a 20-80 times speedup. The proposed approach is evaluated on both the publicly available data sets and our own data set with large images. The benefits of the proposed unified framework are also demonstrated both qualitatively and quantitatively. The experimental results show that our segmentation method achieves better performance of both boundary recall and error rate than the existing state-of-the-art approaches. © 1991-2012 IEEE. (39 refs.)Main Heading: Image segmentationControlled terms: Laplace transformsUncontrolled terms: Acceleration strategies - Interactive image segmentation - Interactive segmentation - Laplacians - Normalized cuts - Optimization method - Segmentation methods - State-of-the-art approachClassification Code: 741.1 Light/Optics - 921.3 Mathematical Transformations

Database: Compendex

Design and fabrication of tapered microfiber waveguide with good optical and mechanical performance

Ma, Cheng-Ju1, 2, 3; Ren, Li-Yong1; Xu, Yi-Ping1, 2; Wang, Ying-Li1; Liang, Jian1; Qu, En-Shi1 Source: Journal of Modern Optics, v 61, n 8, p 683-687, May 4, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.909541;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 School of Science, Xi'an Shiyou University, Xi'an, China

Abstract: In this paper, the inherent dependence of optical and mechanical characteristics of tapered microfiber waveguide on its contour profile is studied. Both theoretical analysis and experimental investigation are given. In theory, the optimal profile parameters of the tapered microfiber are proposed to improve the microfiber performance, where it is better to make the tapered microfiber keep two longer than 5-mm-long transition regions which have a decaying exponential profile. And the uniform waist diameter of the tapered microfiber should be more than 600 nm and less than 1 μm. In this case, the microfiber indicates several favorable advantages, such as low loss, strong evanescent field and relatively shorter transition region. In experiment, according to the profile parameters we proposed, we successfully fabricated a tapered microfiber with a low loss of 0.05 dB in air and 0.8 dB on a MgF <inf>2</inf> substrate at the wavelength of 1550 nm, and it has low surface roughness. © 2014 Taylor & Francis. (29 refs.)Main Heading: WaveguidesControlled terms: Decay (organic) - Evanescent fields - Surface roughnessUncontrolled terms: contour profile - Experimental investigations - Low surface roughness - Mechanical characteristics - Mechanical performance - Micro-fiber - Profile parameters - Transition regionsClassification Code: 701 Electricity and Magnetism - 714.3 Waveguides - 811.2 Wood and Wood Products - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

Effects of stitching pattern on diffractive telescope image quality

Zhang, ZhouFeng1; Xie, YongJun1; Kang, FuZeng1; Wang, YanJun1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9142, 2014, Selected Papers from Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628410938; DOI: 10.1117/12.2054364; Article number: 91421M; Conference: Conferences of the Photoelectronic Technology Committee of the Chinese Society of Astronautics: Optical Imaging, Remote Sensing, and Laser-Matter Interaction 2013, October 20, 2013 - October 29, 2013; Sponsor: Chinese Society of Astronautics; ducation, Shanghai Jiaotong University; Education and Training Department, China; Key Laboratory for Laser Plasmas, Ministry of E; Ordnance Society; Photoelectronic Technology Professional Committee,;

Publisher: SPIEAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Diffraction image technology is an updated technology. It has more potential for developing the larger aperture and lightweight telescope than the conventional refractive and reflective optics. In order to develop a large aperture diffractive telescope, the key is to solve the problem of large aperture lens stitching. Different stitching patterns have different effects on the image quality. However, the stitching pattern for diffractive telescope is different from the conventional refractive and reflective telescope. This paper, for the first time, studies the theory of stitching pattern for diffractive telescope. On the basis of theoretical analysis, a long-wavelength infrared diffractive telescope of segmented-lens is designed and for the first time, good results through stitching experiments have been achieved. According to theoretical analysis and experiment verification, the paper gives the best stitching pattern on diffractive telescope. © 2014 Copyright SPIE. (7 refs.)Main Heading: TelescopesControlled terms: Diffraction - Experiments - Image quality - Optical image storage - Remote sensing - TechnologyUncontrolled terms: Different effects - Diffraction images - Experiment verification - Large aperture - Large aperture lens - Lightweight telescope - Long-wavelength infrared - Reflective opticsClassification Code: 657 Space Physics - 731.1 Control Systems - 741 Light, Optics and Optical Devices - 901 Engineering Profession - 901.3 Engineering Research

Database: Compendex

Phase retrieval without unwrapping by single-shot dual-wavelength digital holography

Min, Junwei1; Yao, Baoli1; Zhou, Meiling1; Guo, Rongli1; Lei, Ming1; Yang, Yanlong1; Dan, Dan1; Yan, Shaohui1; Peng, Tong1 Source: Journal of Optics (United Kingdom), v 16, n 12, December 1, 2014

; ISSN: 20408978, E-ISSN: 20408986; DOI: 10.1088/2040-8978/16/12/125409; Article number: 125409;

Abstract: A phase retrieval method by using single-shot dual-wavelength digital holography is proposed. Each single wavelength hologram is extracted from the color CCD recorded hologram at one exposure, and the unwrapped phase image of object can be reconstructed directly. Different from the traditional multiple wavelength phase unwrapping techniques, any single complex wavefronts at different wavelengths have no need to be calculated any more. Thus, the phase retrieval is computationally fast and straightforward, and the limitations on the total optical path difference are significantly relaxed. The practicability of the proposed method is demonstrated by both simulated and experimental results. (28 refs.)Main Heading: HologramsControlled terms: Computer generated holography - Phase shiftersUncontrolled terms: Color holography - Digital holography - Interference microscopy - Multiple wavelengths - Optical path difference - Phase retrieval - Phase unwrapping - Single wavelengthClassification Code: 703.1 Electric Networks - 743 Holography - 743.1 Holographic Techniques

Database: Compendex

Learning deep and wide: A spectral method for learning deep networks

Shao, Ling1, 2; Wu, Di2; Li, Xuelong3 Source: IEEE Transactions on Neural Networks and Learning Systems, v 25, n 12, p 2303-2308, December 1, 2014

; ISSN: 2162237X, E-ISSN: 21622388; DOI: 10.1109/TNNLS.2014.2308519; Article number: 6763063;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, United Kingdom3 Center for Optical Imagery Analysis and Learning, State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Xi'an, China

Abstract: Building intelligent systems that are capable of extracting high-level representations from high-dimensional sensory data lies at the core of solving many computer vision-related tasks. We propose the multispectral neural networks (MSNN) to learn features from multicolumn deep neural networks and embed the penultimate hierarchical discriminative manifolds into a compact representation. The low-dimensional embedding explores the complementary property of different views wherein the distribution of each view is sufficiently smooth and hence achieves robustness, given few labeled training data. Our experiments show that spectrally embedding several deep neural networks can explore the optimum output from the multicolumn networks and consistently decrease the error rate compared with a single deep network. (32 refs.)Main Heading: Computer visionControlled terms: Intelligent buildings - Intelligent systemsUncontrolled terms: Building intelligent systems - Compact representation - Complementary property - Deep neural networks - Labeled training data - Multi-spectral - representation learning - Spectral methodsClassification Code: 402 Buildings and Towers - 723.4 Artificial Intelligence - 723.5 Computer Applications

Database: Compendex

Rank preserving discriminant analysis for human behavior recognition on wireless sensor networks

Tao, Dapeng1; Jin, Lianwen1; Wang, Yongfei1; Li, Xuelong2 Source: IEEE Transactions on Industrial Informatics, v 10, n 1, p 813-823, February 2014

; ISSN: 15513203; DOI: 10.1109/TII.2013.2255061; Article number: 6490049;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: With the rapid development of the intelligent sensing and the prompt growing industrial safety demands, human behavior recognition has received a great deal of attentions in industrial informatics. To deploy an utmost scalable, flexible, and robust human behavior recognition system, we need both innovative sensing electronics and suitable intelligence algorithms. Wireless sensor networks (WSNs) open a novel way for human behavior recognition, because the heavy computation can be immediately transferred to a network server. In this paper, a new scheme for human behavior recognition on WSNs is proposed, which transmits activities' signals compressed by Hamming compressed sensing to the network server and conducts behavior recognition through a collaboration between a new dimension reduction algorithm termed rank preserving discriminant analysis (RPDA) and a nearest neighbor classifier. RPDA encodes local rank information of within-class samples and discriminative information of the between-class under the framework of Patch Alignment Framework. Experiments are conducted on the SCUT Naturalistic 3D Acceleration-based Activity (SCUT NAA) dataset and demonstrate the effectiveness of RPDA for human behavior recognition. © 2005-2012 IEEE. (80 refs.)Main Heading: Behavioral researchControlled terms: Algorithms - Discriminant analysis - Flexible electronics - Risk management - Servers - Social sciences - Wireless sensor networksUncontrolled terms: Behavior recognition - Human behavior recognition - Industrial informatics - Intelligence algorithms - Intelligent sensing - Nearest Neighbor classifier - rank preserving - Wireless sensor network (WSNs)Classification Code: 922.1 Probability Theory - 922 Statistical Methods - 921 Mathematics - 971 Social Sciences - 732 Control Devices - 722 Computer Systems and Equipment - 715 Electronic Equipment, General Purpose and Industrial - 723 Computer Software, Data Handling and Applications

Database: Compendex

Conservation law of surface roughness in single point diamond turning

Zong, W.J.1; Huang, Y.H.2; Zhang, Y.L.3; Sun, T.1 Source: International Journal of Machine Tools and Manufacture, v 84, p 58-63, September 2014

; ISSN: 08906955; DOI: 10.1016/j.ijmachtools.2014.04.006;

Publisher: Elsevier LtdAuthor affiliation: 1 Center for Precision Engineering, Harbin Institute of Technology, Harbin 150001, China2 Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, China3 Xi'An Institute of Applied Optics, Xi'an 710065, China

Abstract: In this work, a comprehensive model is established to predict the surface roughness achieved by single point diamond turning. In addition to the calculation of the roughness components in relation to the kinematics and minimum undeformed chip thickness, the newly developed model also takes the effects of plastic side flow and elastic recovery of materials as machined into account. Moreover, the 'size effect' has also been successfully integrated into the model, i.e. an inflection point appears in the trend line of predicted surface roughness as the ratio of maximal undeformed chip thickness to cutting edge radius (h<inf>Dmax</inf>/r<inf>n</inf>) is equal to one unit. Face turning experiments validate that the maximal prediction error is only 13.35%. As the ratio of h<inf>Dmax</inf>/r<inf>n</inf> is higher than one unit, both the prediction and experiments reveal that a conservation law exists in diamond turned surface roughness, owing to the competitive effects of kinematics, minimum undeformed chip thickness, plastic side flow and elastic recovery of materials on surface formation. Under the conservation law, the freedom control for an invariable surface roughness can be fulfilled in response to a quantitative ratio of h<inf>Dmax</inf>/r<inf>n</inf>, either through an accurate configuration of feed rate and depth of cut with fixed tool nose radius and cutting edge radius, or by a reasonable selection of tool nose radius and controlled cutting edge radius with designed feed rate and depth of cut. © 2014 Elsevier Ltd. (21 refs.)Main Heading: Surface roughnessControlled terms: Cutting tools - Elasticity - Experiments - Forecasting - Kinematics - Physical properties - TurningUncontrolled terms: Competitive effects - Comprehensive model - Cutting edge radius - Diamond turning - Diamond-turned surfaces - Roughness components - Single point diamond turning - Undeformed chip thicknessClassification Code: 604.2 Machining Operations - 605 Small Tools and Hardware - 901.3 Engineering Research - 921 Mathematics - 931.1 Mechanics - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

An improved blind deconvolution algorithm of motion blurred image

Yang, Lei1; Wang, Ze-Feng1; Guo, Hui-Nan1; Liu, Guang-Sen1; Wang, Hao1; Tang, Li-Nao1; Yang, Hong-Tao1 Source: Applied Mechanics and Materials, v 668-669, p 1046-1049, 2014

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038353126; DOI: 10.4028/www.scientific.net/AMM.668-669.1045; Conference: 3rd Asian Pacific Conference on Mechanical Components and Control Engineering, ICMCCE 2014, September 20, 2014 - September 21, 2014; Sponsor: Nankai University;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xian Institute of Optics and Precision Mechanics Chinese Academy of Sciences, Xian, China

Abstract: An improved blind deconvolution algorithm has been proposed to tackle the image blurring caused by movement. Firstly, take the model to analyze the blurred image and identify the high-frequency of the blurred image through the reasonable pre-estimation of blind kernel function. Then, further estimate the blurring matrix K by the use of the high-frequency while the high-frequency of the blurred image and the accuracy of the blurred image matrix have been improved gradually through normalized iteration. Finally, the clear image has been gained by the use of blind matrix deconvolution. Experimental results show that by the use of this algorithm the image has better subjective visual effect. The proposed algorithm has better restoration effect on the fused motion blurred image and the natural camera motion blurred image. © (2014) Trans Tech Publications, Switzerland. (10 refs.)Main Heading: DeconvolutionControlled terms: Algorithms - Blind source separation - Convolution - Frequency estimation - Image reconstruction - Iterative methods - RestorationUncontrolled terms: Blind deconvolution - Blind deconvolution algorithms - Blind kernel - High frequency HF - Kernel function - Motion blurred image - Pre-estimation - Visual effectsClassification Code: 402 Buildings and Towers - 409 Civil Engineering, General - 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

High-efficiency terahertz-wave generation in silicon waveguides

Liu, Hongjun1; Li, Shaopeng1; Wang, Zhaolu1; Huang, Nan1; Sun, Qibing1 Source: Advanced Solid State Lasers, ASSL 2014, November 16, 2014; ISBN-13: 9781557528223; Conference: Advanced Solid State Lasers, ASSL 2014, November 16, 2014 - November 21, 2014; Sponsor: American Elements; DILAS; IPG Photonics; Qpeak; Thorlabs;

Abstract: Terahertz (THz) wave generation via four-wave mixing (FWM) in silicon waveguides are investigated with mid-infrared pump. The maximum conversion efficiency of 1.37 % is realized when the pump peak power of 2000 W. © OSA 2014. (5 refs.)Main Heading: Terahertz wavesControlled terms: Four wave mixing - Solid state lasers - WaveguidesUncontrolled terms: High-efficiency - Midinfrared - Peak power - Silicon waveguide - Terahertz wave generationClassification Code: 711 Electromagnetic Waves - 711.1 Electromagnetic Waves in Different Media - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides

Database: Compendex

Switchable linear-cavity nanotube-mode-locking fiber laser emitting picosecond or femtosecond pulses

Yao, Xiankun1 Source: Optics Communications, v 335, p 262-265, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.09.036;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: A switchable linear-cavity nanotube-mode-locking fiber laser is proposed by exploiting fiber Bragg grating for the first time to the author's best knowledge. The proposed all-fiber laser can deliver either picosecond or femtosecond pulses by controlling the polarization controllers. The durations of picosecond and femtosecond pulses are 16.4 ps and 838 fs with the central wavelengths of 1529.5 and 1560 nm, respectively. The femtosecond pulse has symmetrical spectrum sidebands, but the picosecond pulse almost has no spectral sidebands. Our work provides a simple, low-cost, dual-scale pulse source for practical applications. © 2014 Elsevier B.V. All rights reserved. (73 refs.)Main Heading: Ultrashort pulsesControlled terms: Carbon nanotubes - Electromagnetic pulse - Fiber Bragg gratings - Fiber lasers - Fibers - Laser mode locking - Locks (fasteners) - Mode-locked fiber lasers - Ultrafast lasers - YarnUncontrolled terms: Central wavelength - Mode-locked laser - Mode-locking fiber laser - Pico-second pulse - Polarization controllers - Spectral sidebands - Switchable - Symmetrical spectrumClassification Code: 601.3 Mechanisms - 701 Electricity and Magnetism - 741.1.2 Fiber Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 819.4 Fiber Products

Database: Compendex

A method which can enhance the optical -centering accuracy

Zhang, Xue-Min1, 2; Zhang, Xue-Jun2; Dai, Yi-Dan2; Yu, Tao1, 2; Duan, Jia-You1; Li, Hua1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9282, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413571; DOI: 10.1117/12.2069793; Article number: 92821G; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 Graduate University of Chinese Academy of Sciences, Beijing, China

Abstract: Optical alignment machining is an effective method to ensure the co-axiality of optical system. The co-axiality accuracy is determined by optical-centering accuracy of single optical unit, which is determined by the rotating accuracy of lathe and the optical-centering judgment accuracy. When the rotating accuracy of 0.2um can be achieved, the leading error can be ignored. An axis-determination tool which is based on the principle of auto-collimation can be used to determine the only position of centerscope is designed. The only position is the position where the optical axis of centerscope is coincided with the rotating axis of the lathe. Also a new optical-centering judgment method is presented. A system which includes the axis-determination tool and the new optical-centering judgment method can enhance the optical-centering accuracy to 0.003mm. © 2014 SPIE. (12 refs.)Main Heading: ManufactureControlled terms: Alignment - Lathes - Optical systems - Optical testingUncontrolled terms: Judgment method - Optical alignment machining - Optical axis - Optical units - Optical-centering accuracyClassification Code: 537.1 Heat Treatment Processes - 603.1 Machine Tools, General - 741.3 Optical Devices and Systems

Database: Compendex

Design and experimental demonstration of variable curvature mirror having a large saggitus variation

Xie, Xiaopeng1; Zhao, Hui2; Ren, Guorui2; Wei, Jingxuan3; Menke, Neimule4 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9272, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413458; DOI: 10.1117/12.2070987; Article number: 927212; Conference: Optical Design and Testing VI, October 9, 2014 - October 10, 2014; Sponsor: Chinese Optical Society (COS); The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 School of Physical Science and Technology, Inner Mongolia University, No.235 West College Road, Hohhot-Inner-Mongolia, China2 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, No. 17 Xinxi Road, Xi'an, China3 School of Computer Science and Technology, Xidian University, No.2, South Taibai Road, Xi'an, China4 Ordos College, Inner Mongolia University, Ordos, China

Abstract: Variable curvature mirror (VCM) is a simplified active optical component being capable of changing its curvature radius. Curvature radius variation within a wide range requires that the VCM should be able to generate a large saggitus variation. Besides that, the surface form accuracy should be maintained above a reasonable level. In this paper, a piezoelectric actuation based prototype VCM is designed, constructed and experimentally tested. The thickness of the K9 plane mirror is only 3mm over the full aperture of 100mm. Six piezoelectric actuators are fixed into a base plate and the head of each actuator is connected to an annular ring through the screw thread. With such a structure, the force provided by each actuator can be transformed to the mirror backside through this annular ring. With each actuator generating the same force, the curvature radius can be changed in a uniform way. At the mean time, the surface form accuracy could be adjusted one point by point to compensation asymmetric modes as well. Mathematical analysis and FEA (finite element analysis) are used together to demonstrate the theoretical correctness. Besides that, the prototype VCM is successfully constructed and experiments have been carried out to give a quantitative assessment on the saggitus variation.. © 2014 SPIE. (11 refs.)Main Heading: Piezoelectric actuatorsControlled terms: Actuators - Design - Finite element method - Mirrors - Optical design - Piezoelectricity - Screw threadsUncontrolled terms: Asymmetric modes - Curvature radii - Experimental demonstrations - Mathematical analysis - Optical components - Piezoelectric actuation - Quantitative assessments - Variable curvature mirrorClassification Code: 408 Structural Design - 601.2 Machine Components - 632 Hydraulics, Pneumatics and Related Equipment, and Fluidics - 708 Electric and Magnetic Materials - 708.1 Dielectric Materials - 715 Electronic Equipment, General Purpose and Industrial - 732 Control Devices - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

Design of transient light signal simulator based on FPGA

Kang, Jing1, 2; Chen, Rong-Li1; Wang, Hong1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9299, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413854; DOI: 10.1117/12.2070215; Article number: 929908; Conference: International Symposium on Optoelectronic Technology and Application 2014: Optical Remote Sensing Technology and Applications, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: A design scheme of transient light signal simulator based on Field Programmable gate Array (FPGA) was proposed in this paper. Based on the characteristics of transient light signals and measured feature points of optical intensity signals, a fitted curve was created in MATLAB. And then the wave data was stored in a programmed memory chip AT29C1024 by using SUPERPRO programmer. The control logic was realized inside one EP3C16 FPGA chip. Data readout, data stream cache and a constant current buck regulator for powering high-brightness LEDs were all controlled by FPGA. A 12-Bit multiplying CMOS digital-to-analog converter (DAC) DAC7545 and an amplifier OPA277 were used to convert digital signals to voltage signals. A voltage-controlled current source constituted by a NPN transistor and an operational amplifier controlled LED array diming to achieve simulation of transient light signal. LM3405A, 1A Constant Current Buck Regulator for Powering LEDs, was used to simulate strong background signal in space. Experimental results showed that the scheme as a transient light signal simulator can satisfy the requests of the design stably. © 2014 SPIE. (6 refs.)Main Heading: Field programmable gate arrays (FPGA)Controlled terms: Design - Digital integrated circuits - Digital to analog conversion - Light emitting diodes - MATLAB - Operational amplifiers - Remote sensing - Simulators - Space opticsUncontrolled terms: Background signals - Constant current - Digital signals - High brightness LEDs - Light signal - N-p-n transistors - Optical intensities - Voltage controlled current sourcesClassification Code: 408 Structural Design - 621 Nuclear Reactors - 671 Naval Architecture - 713.1 Amplifiers - 721.3 Computer Circuits - 723.2 Data Processing and Image Processing - 731.1 Control Systems - 741.1 Light/Optics - 921 Mathematics

Database: Compendex

Light flow model of coded aperture snapshot spectral imager

Xie, Peiyue1, 2; Yang, Jianfeng1; Xue, Bin1; Wang, Hong1, 2; Song, Yansong1, 2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9298, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413847; DOI: 10.1117/12.2070581; Article number: 92980c; Conference: International Symposium on Optoelectronic Technology and Application 2014: Imaging Spectroscopy; and Telescopes and Large Optics, IPTA 2014, May 13, 2014 - May 15, 2014; Sponsor: China High-Tech Industrialization Association; Chinese Society of Astronautics (CSA);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaan xi, China2 Graduate University of Chinese Academy of Sciences, Beijing, China

Abstract: Coded aperture snapshot spectral imager (CASSI) based on compressed sensing can capture a three-dimensional (3-D) data cube information in one snapshot without scanning, so it is a kind of novel spectral imaging technique with good prospects. In this paper, the data flow procession of two kind of CASSI were studied, which similarities and differences were depicted. The basic principle of the encoded representation of both spectral information and 2-D spatial information of a scene were presented. The numerical estimation techniques based on the compressive sensing theory were applied to reconstruct 3-D data cube. © 2014 SPIE. (10 refs.)Main Heading: Compressed sensingControlled terms: Computation theory - Imaging techniques - Signal reconstruction - Spectroscopy - TelescopesUncontrolled terms: CASSI - computational spectral imager - Numerical estimation - snapshot - Spatial informations - Spectral imaging technique - Spectral information - Threedimensional (3-d)Classification Code: 657 Space Physics - 716.1 Information Theory and Signal Processing - 741 Light, Optics and Optical Devices - 746 Imaging Techniques - 801 Chemistry - 921 Mathematics

Database: Compendex

Direct generation of orthogonally polarized photon pairs via spontaneous non-degenerate FWM on a chip

Reimer, Christian1; Caspani, Lucia1; Jestin, Yoann1; Clerici, Matteo1, 2; Ferrera, Marcello1, 2; Peccianti, Marco1, 3; Pasquazi, Alessia1, 3; Litte, Brent E.4; Chu, Sai T.5; Moss, David J.1, 6; Morandotti, Roberto1 Source: Frontiers in Optics, FiO 2014, October 14, 2014

; ISBN-10: 1557522863;

Publisher: Optical Society of America (OSA)Author affiliation: 1 INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes; QC, Canada2 School of Engineering and Physical Sciences, Heriot-Watt University, SUPA, Edinburgh, United Kingdom3 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, United Kingdom4 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China5 City University of Hong Kong, Department of Physics and Material Science, Tat Chee Avenue, Hong Kong6 School of Electrical and Computer Engineering, RMIT University, Melbourne; VIC, Australia

Abstract: Orthogonally polarized photon pairs are directly generated on a CMOS-compatible chip via spontaneous non-degenerate four-wave-mixing between orthogonally polarized pumps, enabled by suppressing stimulated processes. Photon coincidences and optical parametric oscillation are measured. © OSA 2014. (11 refs.)Main Heading: Four wave mixingControlled terms: PhotonsUncontrolled terms: CMOS Compatible - Degenerate four-wave mixing - Direct generation - Optical parametric oscillations - Polarized photons - Stimulated processClassification Code: 711.1 Electromagnetic Waves in Different Media - 741.1 Light/Optics

Database: Compendex

Effect of space environment on working life of solid-lubricated rotating parts

Shangguan, Ai-Hong1, 2; Mu, You1; Li, Zhi-Guo1; Liu, Zhao-Hui1 Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering, v 22, n 12, p 3264-3271, December 1, 2014; Language: Chinese

; ISSN: 1004924X; DOI: 10.3788/OPE.20142212.3264;

Publisher: Chinese Academy of SciencesAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: To explore the effect of space environment on the working life of solid-lubricated rotating parts and forecast their working life in orbit, the influence of space environment on solid-lubricated films was analyzed. The analysis points out that three main factors are relative to the working life of the space rotating parts, which are space launch environment, vacuum degree and alternating temperature. A life test was designed to simulate the three factors, in which the mechanical test was used to simulate space launch environment, and the thermal vacuum test was taken to simulate the vacuum and alternating temperature. The X-ray Energy Dispersive Spectrometer (EDS) was used to analyze the film composition of the unworn race and the worn race for a bearing in the solid-lubricated rotating part as well as ball surface materials. The analysis results show that the transfer film has not formed. On the result, it forecasts that the working life of the solid-lubricated rotating part in the test would be up to 107 times. Finally, it gives some necessary suggests that should been taken to increase the reliability and improve the work life of space rotating parts. (10 refs.)Main Heading: LubricationControlled terms: Spectrometers - Vacuum technologyUncontrolled terms: Film composition - Rotating parts - Solid lubrication - Space environment - Surface materials - Thermal vacuum tests - Vacuum degree - X-ray energy dispersive spectrometersClassification Code: 607.2 Lubrication - 633 Vacuum Technology - 801 Chemistry

Database: Compendex

Frequency non-degenerate phase-sensitive optical parametric amplification based on fourwave-mixing in width-modulated silicon waveguides

Wang, Zhaolu1; Liu, Hongjun1; Sun, Qibing1; Huang, Nan1; Li, Xuefeng2 Source: Optics Express, v 22, n 25, p 31486-31495, December 15, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.031486;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, China2 School of Science, Xi'an University of Post and Telecommunications, Xi'an, China

Abstract: A width-modulated silicon waveguide is proposed to realize nondegenerate phase sensitive optical parametric amplification. It is found that the relative phase at the input of the phase sensitive amplifier (PSA) θIn-PSA can be tuned by tailoring the width and length of the second segment of the width-modulated silicon waveguide, which will influence the gain in the parametric amplification process. The maximum gain of PSA is larger by 9 dB compared with the phase insensitive amplifier (PIA) gain, and the gain bandwidth of PSA is larger by 35 nm compared with the gain bandwidth of PIA. Our on-chip PSA can find important potential applications in highly integrated optical circuits for optical chip-to-chip communication and computers. (31 refs.)Main Heading: Optical parametric amplifiersControlled terms: Bandwidth - Optical communication - Photonic integration technology - Silicon - WaveguidesUncontrolled terms: Gain bandwidth - Integrated optical circuit - Optical parametric amplification - Parametric amplification - Phase sensitive - Phase-insensitive amplifiers - Phase-sensitive amplifiers - Silicon waveguideClassification Code: 712.1.1 Single Element Semiconducting Materials - 714 Electronic Components and Tubes - 716.1 Information Theory and Signal Processing - 717.1 Optical Communication Systems

Database: Compendex

Color fusion system of low-light level and infrared images based on multi-core DSP

Deng, Chan1, 2; Liu, Wen1; Huang, Biao1, 2; Zhan, Zhenhuan1, 2; Zhang, Xin1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 9, p 3141-3145, September 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: For the color fusion of low-level light and infrared images have the characteristics of strong real-time performance and a large quantity of data, a low-level light and infrared dual channel real-time image fusion system based on multi-core digital signal processor (DSP) and field programmable gate array (FPGA) was put forward. Cyclone IV FPGA of Altera Co.Ltd. with serial transceivers was chose to complete the image information collection, preprocessing and all kinds of control of peripheral equipment, while the newest 8 core high performance fixed point and floating point DSP TMS320C6678 of TI Co. Ltd. was used to realize image fusion. The data transmission was achieved between field programmable gate array and multi-core digital signal processor through the high-speed Serial RapidIO (SRIO) interface, and then color transmission in YUV color space as well. When the color information of the color image in the day light was passed to the fusion image, it was closer to natural color and could reflect richer scene information as much as possible. Experiment shows that this system can realize realtime image fusion and useful color transmission, is suitable for the color fusion system applications of the dual channel video natural sense in the dynamic scenarios. (8 refs.)Main Heading: Image fusionControlled terms: Color - Color image processing - Digital arithmetic - Digital signal processing - Digital signal processors - Field programmable gate arrays (FPGA) - Image enhancement - Infrared imaging - Infrared radiation - Logic gates - Signal processingUncontrolled terms: Color fusion - Color information - Digital signal processors (DSP) - Dual-channel videos - Multi-core dsp - Peripheral equipment - Real time performance - Real-time image fusionsClassification Code: 716.1 Information Theory and Signal Processing - 721.3 Computer Circuits - 723.2 Data Processing and Image Processing - 741.1 Light/Optics - 746 Imaging Techniques - 921.6 Numerical Methods

Database: Compendex

Integrated source of multiplexed heralded photons

Reimer, Christian1; Caspani, Lucia1; Clerici, Matteo1, 2; Ferrera, Marcello1, 2; Kues, Michael1; Peccianti, Marco1, 3; Pasquazi, Alessia1, 3; Razzari, Luca1; Little, Brent E.4; Chu, Sai T.5; Moss, David J.1, 6; Morandotti, Roberto1 Source: Proceedings - 2014 Summer Topicals Meeting Series, SUM 2014, p 142-143, September 18, 2014; ISBN-13: 9781479927678; DOI: 10.1109/SUM.2014.80; Article number: 6903028; Conference: 2014 Summer Topicals Meeting Series, SUM 2014, July 14, 2014 - July 16, 2014; Sponsor: IEEE Photonics Society;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes; QC, Canada2 School of Engineering and Physical Sciences, Heriot-Watt University, SUPA, Edinburgh, United Kingdom3 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, United Kingdom4 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China5 City University of Hong Kong, Department of Physics and Material Science, Tat Chee Avenue, Hong Kong6 School of Electrical and Computer Engineering, RMIT University, Melbourne; VIC, Australia

Abstract: We report an integrated, CMOS-compatible source of multiplexed heralded photons, distributed over several wavelengths at standard communication channels and compatible with quantum memories. Our system operates in a self-locked mode without an external pump laser. © 2014 IEEE. (7 refs.)Main Heading: MultiplexingControlled terms: Photons - Pumping (laser)Uncontrolled terms: CMOS Compatible - Heralded photons - Integrated sources - Locked mode - Pump laser - Quantum memoryClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741.1 Light/Optics - 744.1 Lasers, General

Database: Compendex

Measuring the fractional topological charge of LG beams by using interference intensity analysis

Li, Xinzhong1, 2; Tai, Yuping3; Lv, Fangjie1; Nie, Zhaogang4 Source: Optics Communications, v 334, n 1, p 235-239, January 1, 2015

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.08.020;

Publisher: ElsevierAuthor affiliation: 1 School of Physics and Engineering, Henan University of Science and Technology, Luoyang, China2 State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, China3 School of Chemical Engineering and Pharmaceutics, Henan University of Science and Technology, Luoyang, China4 School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore

Abstract: We demonstrate a method to measure the fractional topological charge (TC) of Laguerre-Gaussian (LG) beams by analyzing the interference intensity patterns between the vortex beam and its conjugate beam. By this method, the magnitude of integer and fractional TCs is quantitatively measured by using a simple unified formula. The proposed method can measure TCs up to 60. © 2014 Elsevier B.V. (27 refs.)Main Heading: Gaussian beamsControlled terms: Measurements - Topology - Vortex flowUncontrolled terms: Conjugate beams - Interference intensity - Laguerre-Gaussian beam - LG beams - Optical vortices - Singular optics - Topological charges - Vortex beamsClassification Code: 631.1 Fluid Flow, General - 711 Electromagnetic Waves - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Iterative interpolation algorithm of Bayer images based on color difference space

Liang, Xiaofen1, 2; Qiao, Weidong1; Yang, Jianfeng1; Xue, Bin1; Qin, Jia1, 2 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 9, p 3128-3133, September 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: Signal CCD/CMOS sensors capture image information by covering the sensor surface with a color filter array (CFA). For each pixel, only one of three primary colors(red, green and blue) can pass through the CFA. The other two missing color components are estimated by the values of surrounding pixels. The first step was to estimate interpolation direction taking advantage of the pixels in 5×5 template and use the optimal weighting factors to interpolate G components. The second step was to interpolate R(B) components at the location of B(R) using the interpolation operator based on two-dimensional rational function. The third step was to interpolate R and B components at the location of G components by color difference interpolation. Lastly, the iterative interpolation repeated until approaching the optimal results using variance-constrained condition. Through Matlab simulate experiments based on 24 Kodak images and the images captured from our camera, the proposed algorithm outperforms both in visual and numerical aspects. (10 refs.)Main Heading: ColorControlled terms: Algorithms - Color image processing - Colorimetry - Interpolation - Iterative methods - MATLAB - Pixels - Rational functionsUncontrolled terms: Bilinear interpolation - Color interpolation - Color recovery - Constrained conditions - Interpolation algorithms - Interpolation operator - PSNR - Red , green and bluesClassification Code: 723.5 Computer Applications - 741.1 Light/Optics - 921 Mathematics - 921.6 Numerical Methods - 941.4 Optical Variables Measurements

Database: Compendex

Design of high power light absorber

Li, Hongguang1; Da, Zhengshang1; Sun, Ce1; Dong, Xiaona1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 7, p 2209-2213, July 25, 2014; Language: Chinese

; ISSN: 10072276;

Publisher: Chinese Society of AstronauticsAuthor affiliation: 1 Laboratory of Advanced Optical Technique, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: In order to realize the 109 times absorption for residual laser after 4% sampling, a kind of design method of light absorber was given. From light entrance to light exit the absorber, total angle relations were derived, including the angle of entrance light intersection with the absorber, turnover angle from entrance to exit, the angle of exit light intersection with the absorber, and turnover angle of the light departure from the absorber. The calculated angles were taken into polarization formula, and the sampling efficiency from every intersection was gotten, and so the total process attenuation was obtained from light entrance to light exit the absorber. According to the above formulas, a kind of absorber was designed, and it was analyzed in optical software. The results show that the absorption can reach to 1011, which satisfies the absorption requirements and is identical with theory calculation; This kind of absorber has been used in the laser system well, near field image with modulation M<1.2 and contrast C<0.07 are gotten, so the design method is reasonable. (9 refs.)Main Heading: Laser theoryControlled terms: Optical designUncontrolled terms: Angle relation - Critical angles - Laser systems - Light absorbers - Near-field images - Optical software - Sampling efficiency - Theory calculationClassification Code: 741.1 Light/Optics - 744.1 Lasers, General

Database: Compendex

Rejection of time-varying disturbances in inertial platform stabilizing system via unfalsified control

Dong, Xiao-Kun1, 2; Cao, Jian-Zhong1; Liu, Chen1, 2; Fan, Xin-Ming1, 2; Yang, Lei1 Source: Kongzhi Lilun Yu Yingyong/Control Theory and Applications, v 31, n 9, p 1206-1212, September 1, 2014; Language: Chinese

; ISSN: 10008152; DOI: 10.7641/CTA.2014.31099;

Publisher: South China University of TechnologyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an ; Shaanxi , China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: The unfalsified control is a control method based on online data. This paper realizes the diversified operations of candidate controllers with the evolution strategy, and combines hysteresis switching algorithm with the switch controllers to achieve the adaptive PID controller. Because of the nonlinear time-varying disturbances in the inertial stabilizing system, we cannot obtain an accurate control model for the controlled object; however, by adopting the unfalsified control algorithm, we can stabilize the inertial stabilizing system with good results such as the azimuth errors less than 3.4 mrad and pitch errors less than 4.36 mrad. (8 refs.)Main Heading: Time varying control systemsControlled terms: Adaptive control systems - Algorithms - Controllers - Errors - Hysteresis - Three term control systemsUncontrolled terms: Adaptive-pid controls - Evolutionary method - Hysteresis switching - Inertial - platform stabilizing system - Unfalsified controlClassification Code: 723 Computer Software, Data Handling and Applications - 731 Automatic Control Principles and Applications - 731.1 Control Systems - 732.1 Control Equipment - 921 Mathematics - 961 Systems Science

Database: Compendex

An improved method of edge detection based on the mean shift algorithm

Wei, Laixing1; Liu, Bo1; Mou, Jiao1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9284, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413595; DOI: 10.1117/12.2069468; Article number: 928412; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: This paper proposes an improved method of edge detection based on the mean shift algorithm. A pixel of an image calculated by the mean shift algorithm eventually converges to a peak point of probability density of the image. The pixel which is farther from the peak point has a greater mean shift vector and higher probability to be an edge pixel. The gradient of the mean shift vector of an edge pixel is a local maximum. During the mean shift iterations, the mean shift vector decreases by steps. Therefore, the vector of the first step is representative, while it is unnecessary to calculate each pixel to its convergence. This reduces the amount of computation and promotes the efficiency of the algorithm in a large extent. First, the image is smoothed by the mean shift filter, and the gradient of the mean shift vector is computed. Then, the local maximum is found by using non-maxima suppression on the gradient, which thins the edges detected. Finally, dual-threshold is used to detect and link edges. The edges detected have more accuracy and continuity. Experimental results show that the proposed method outperforms the conventional methods while suppressing noise and preserving edges. (9 refs.)Main Heading: AlgorithmsControlled terms: Computational efficiency - Edge detection - Manufacture - Materials testing - Optoelectronic devices - Pixels - Probability density function - VectorsUncontrolled terms: Conventional methods - Image smoothing - Mean shift - Mean shift algorithm - Mean shift vector - Non-maxima suppressions - Probability densities - Suppressing noiseClassification Code: 422 Strength of Building Materials; Test Equipment and Methods - 423 Non Mechanical Properties and Tests of Building Materials - 537.1 Heat Treatment Processes - 716 Telecommunication; Radar, Radio and Television - 717.2 Optical Communication Equipment - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 921 Mathematics - 921.1 Algebra - 951 Materials Science

Database: Compendex

Automatic segmentation of breast lesions for interaction in ultrasonic computer-aided diagnosis

Huang, Qinghua1; Yang, Feibin1; Liu, Longzhong2; Li, Xuelong3 Source: Information Sciences, June 18, 2013

; ISSN: 00200255; DOI: 10.1016/j.ins.2014.08.021 Article in PressAuthor affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, Guangdong, PR China2 The Cancer Center of Sun Yat-sen University, Guangzhou, PR China3 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, PR China

Abstract: Breast cancer is one of the most commonly diagnosed cancer types among women. Sonography has been regarded as an important imaging modality for diagnosis of breast lesions. Due to the speckle and the variance in shape and appearance of sonographic lesions, fully automatic segmentation of the breast tumor regions still remains a challenging task. In this paper, we propose an automatic interaction scheme based on an object recognition method to segment the lesions in breast ultrasound images. In this scheme, a 2D ultrasound image is firstly filtered with a total-variation model to reduce the speckle noise. A robust graph-based segmentation method is then used to segment the image into a number of sub-regions. An object recognition method incorporating the procedures of image feature extraction, feature selection and classification is proposed to automatically identify the regions which are associated with breast tumors. Finally, an active contour model is used to refine the contours of the regions that are recognized as tumors. This scheme is validated on a database of 46 breast ultrasound images with diagnosed tumors. The experimental results show that our scheme can segment the breast ultrasound images automatically, indicating its good performance in real applications. © 2014 Elsevier Inc.Main Heading: Medical imagingControlled terms: Computer aided diagnosis - Diseases - Feature extraction - Image segmentation - Object recognition - Speckle - Tumors - Ultrasonic applications - UltrasonographyUncontrolled terms: Active contour model - Automatic interactions - Automatic segmentations - Breast ultrasound images - Feature selection and classification - Graph-based segmentation - Image feature extractions - Real applicationsClassification Code: 461 Bioengineering and Biology - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 746 Imaging Techniques - 753.3 Ultrasonic Applications

Database: Compendex

Refraction angle extracting strategy for fan-beam differential phase contrast CT

Ye, Renzhen1; Tang, Yi2; Lu, Xiaoqiang3 Source: Neurocomputing, v 141, p 160-169, October 2, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2014.03.040;

Publisher: ElsevierAuthor affiliation: 1 College of Sciences, Huazhong Agricultural University, Wuhan 430074, Hubei, China2 School of Mathematics and Computer Science, Yunnan University of Nationalities, Kunming, 650500 Yunnan, China3 The Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: In this paper, the fan-beam differential phase contrast computed tomography (DPC-CT) reconstruction method is studied. We first present a new vision of how to implement the Reverse-Projection (RP) method to extract the refraction-angle data efficiently in fan-beam geometry, and then provide a Katsevich-type formula for fan-beam DPC-CT reconstruction. The proposed method has two key properties. First, it is essentially a filtered back projection (FBP) reconstruction formula. Second, it can deal with incomplete data sets. The main contributions of this paper lie in the following three aspects: First, the physical principle of the bent-grating based fan-beam DPC imaging is discussed and the RP-method is extended to the fan-beam case. Second, an implementation strategy of Katsevich algorithm for fan-beam DPC-CT is proposed. Third, a semi-quantitative research on the influence of the approximation errors introduced by the RP-method is carried out by using several numerical simulations. It should be pointed out that the RP-method will certainly introduce some errors. The effect of these errors on our reconstruction algorithm is discussed by several numerical simulations. © 2014 Elsevier B.V. (42 refs.)Main Heading: Computerized tomographyControlled terms: Computer simulation - Errors - Numerical modelsUncontrolled terms: Differential phase contrast - Fan-beam CT - Filtered back projection - Implementation strategies - Phase-contrast image - PI-line - Reconstruction algorithms - Xray imagingClassification Code: 723.5 Computer Applications - 921 Mathematics

Database: Compendex

Resolution and visibility of two-color pseudothermal lensless ghost imaging

Xue, Yu-Lang1, 2; Wan, Ren-Gang1; Feng, Fei1, 2; Zhang, Tong-Yi1 Source: Optik, v 125, n 16, p 4452-4455, August 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.02.029;

Abstract: Two-color (or nondegenerate-wavelength) lensless ghost imaging using pseudothermal light source is investigated theoretically by use of classical optical coherence theory. We find that for two-color pseudothermal lensless ghost imaging the visibility and resolution is determined by (Δ) the product of the wavelength and the corresponding path length rather than the wavelength for each path or the path length. We also confirm our theoretical conclusion by numerical simulations. The result shows we must make a trade-off between resolution and visibility in devise practical experiments, as the resolution of the imaging can be improved by decreasing Δ but with visibility getting poor, and vice versa. © 2014 Elsevier GmbH. All rights reserved. (30 refs.)Main Heading: VisibilityControlled terms: Color - Imaging techniques - Light sourcesUncontrolled terms: Ghost imaging - Path length - Pseudothermal light source - Two-colorClassification Code: 741 Light, Optics and Optical Devices - 746 Imaging Techniques

Database: Compendex

Polarization-sensitive diffractive optical elements fabricated in BR films with femtosecond laser

Yu, Xianghua1; Yao, Baoli1; Lei, Ming1; Hampp, Norbert2; Liang, Yansheng1; Dan, Dan1; Yang, Yanlong1; Yan, Shaohui1; Gao, Peng1; Ye, Tong1 Source: Applied Physics B: Lasers and Optics, v 115, n 3, p 365-369, June 2014

; ISSN: 09462171; DOI: 10.1007/s00340-013-5611-2;

Publisher: Springer VerlagAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Department of Chemistry, University of Marburg, 35032 Marburg, Germany

Abstract: Multi-photon product (F<inf>540</inf>-state) of bacteriorhodopsin (BR) polymeric films excited by femtosecond laser shows permanently photoinduced birefringence and dichroism. Based on this property, polarization-sensitive diffractive optical elements (PDOEs), e.g., gratings, two-dimensional optical lattice, Bessel zone plate, were firstly fabricated and investigated in BR films by femtosecond laser multi-beam interference with rotationally symmetric pyramid lenses. These fabricated PDOEs are completely stable at room temperature. The dependence of diffraction efficiency on the incident polarization state was measured. The micro-structures of PDOEs were observed under polarization microscope, and the selective readout diffraction patterns from the polarization-multiplexed PDOEs were demonstrated. © 2013 Springer-Verlag Berlin Heidelberg. (22 refs.)Main Heading: PolarizationControlled terms: Density (optical) - Diffractive optical elements - Excited states - Fabrication - Ultrashort pulsesUncontrolled terms: Bacteriorhodopsin (bR) - Incident polarization state - Multibeam interferences - Multiphotons - Photoinduced birefringence - Polarization microscopes - Room temperature - Two-dimensional optical latticesClassification Code: 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 913.4 Manufacturing - 931.3 Atomic and Molecular Physics

Database: Compendex

Simple method of optical ring cavity design and its applications

Wen, Qiao1, 2; Zhang, Xiaojun1, 2; Liang, Zongsen1, 2; Wang, Yonggang3; Sun, Liqun4; Niu, Hanben2 Source: Optics Express, v 22, n 12, p 14782-14791, June 16, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.014782;

Publisher: Optical Society of American (OSA)Author affiliation: 1 Key Laboratory of Optoelectronic Devices and Systems, Shenzhen University, Ministry of Education and Guangdong Province, Shenzhen 518060, China2 Key Laboratory of Micro-Nano Measuring and Imaging in Biomedical Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China3 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian 710119, China4 State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing 100084, China

Abstract: When an optical ring cavity is designed, the beam radii at some special positions, especially at the beam waists are very interested in, since the gain mediums, nonlinear crystals and others important optical elements are generally located at the beam waist. In this paper, we firstly presented a simple method for designing optical ring cavities based on the selfconsistency theory and the fact that q parameter is uniquely determined by the waist beam radius and its position. This approach is different from ABCD method and it no longer requires cumbersome calculation. The calculations of designing optical ring cavities are simplified because q parameter only has imaginary part at beam waist plane. Moreover, designing the resonant cavity through the calculation of beam waist radii and their position has great practical significance, because it is very easy to adjust the waist radii and the positions at the important optical elements. We employed this method to design an end-pumped six-mirror ring cavity continuous-wave passively mode locked laser. The experiment of a highly stabilized continuous-wave mode locked (CWML) laser was investigated and the results coincided with the theoretical studies very well. The investigation results show that the simple method can be used to design optical ring cavities conveniently, intuitively and efficiently. © 2014 Optical Society of America. (17 refs.)Main Heading: Laser mirrorsControlled terms: Design - Locks (fasteners) - Optics - Passive mode locking - Pumping (laser)Uncontrolled terms: Continuous wave modes - Continuous waves - Nonlinear crystals - Optical ring cavity - Passively mode-locked lasers - Self-consistency theory - Special positions - Theoretical studyClassification Code: 408 Structural Design - 601.3 Mechanisms - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General - 744.7 Laser Components

Database: Compendex

Abnormal ripple patterns with enhanced regularity and continuity in a bulk metallic glass induced by femtosecond laser irradiation

Zhang, W.1, 2; Cheng, G.3; Hui, X.D.1; Feng, Q.1, 4 Source: Applied Physics A: Materials Science and Processing, v 115, n 4, p 1451-1455, June 2014

; ISSN: 09478396, E-ISSN: 14320630; DOI: 10.1007/s00339-013-8062-z;

Publisher: Springer HeidelbergAuthor affiliation: 1 State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083, China2 National Key Laboratory of Science and Technology on Power Beam Processes, Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China4 National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083, China

Abstract: Two types of abnormal ripple patterns: classical ripples (C-ripples) with continuous ridges and unclassical ripples (U-ripples) with regular micropores were investigated in a Zr-based bulk metallic glass (Zr-BMG) after femtosecond laser beam irradiation. U-ripples with a period of &sim; 1,600 nm and the orientation nearly parallel to the polarization of laser beam were observed to form gradually on the top of C-ripples with the effective pulse number. Micropores created by the superposition of C-ripples and U-ripples had an average diameter of &sim; 750 nm nearly equal to the period of C-ripples (&sim; 720 nm) and ran along parallel lines in the grooves of U-ripples. Both U-ripples and C-ripples in Zr-BMG showed significant microstructural differences comparing with those in a conventional Zr-based alloy with the same composition and processing conditions, including much more regular and continuous ridges. The results indicate that the amorphous structure in Zr-BMG plays a key role in the uniform morphology of laser-induced structures. © 2013 Springer-Verlag Berlin Heidelberg. (22 refs.)Main Heading: ZirconiumControlled terms: Glass - Laser beams - Microporosity - Ultrashort pulsesUncontrolled terms: Amorphous structures - Average diameter - Bulk metallic glass - Laser-induced structures - Micro-structural - Processing condition - Ripple patterns - Zr based bulk metallic glassClassification Code: 549.3 Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals - 744.1 Lasers, General - 744.8 Laser Beam Interactions - 812.3 Glass - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

Oxygen-implanted optical planar waveguides in Er3+/Yb 3+ -codoped silicate glasses for integrated laser generation

Liu, Chun-Xiao1, 2; Xu, Jun3; Xu, Xiao-Li1; Wu, Shu1; Wei, Wei2, 4; Guo, Hai-Tao2; Li, Wei-Nan2; Peng, Bo2, 4 Source: Optical Engineering, v 53, n 3, March 2014

; ISSN: 00913286, E-ISSN: 15602303; DOI: 10.1117/1.OE.53.3.037101; Article number: 037101;

Publisher: SPIEAuthor affiliation: 1 Hefei Normal University, School of Electronic and Information Engineering, Hefei 230601, China2 Chinese Academy of Sciences, Xi'an Institute of Optics and Precision Mechanics, State Key Laboratory of Transient Optics and Photonics, Xi'an 710119, China3 East China Jiaotong University, School of Information Engineering, Nanchang 330013, China4 Nanjing University of Posts and Telecommunications, School of Optoelectronic Engineering, Nanjing 210046, China

Abstract: Er3+/Yb3+-codoped silicate glasses are good candidates for the application of laser actions and signal amplification. Optical planar waveguides in Er3+/Yb3+-codoped silicate glasses are fabricated by 6.0-MeV oxygen-ion implantation with a dose of 6.0 × 1014 ions/cm2 at room temperature. The SRIM 2010 code is carried out to simulate the energy losses during the implantation process in order to obtain a better understanding of the waveguide formation. The guiding modes and near-field intensity distributions of the waveguide are characterized by the prism-coupling and end-face coupling methods. The refractive index profile and light propagation mode of the planar waveguide are numerically calculated by the reflectivity calculation method and finite difference beam propagation method. The waveguide has "well + barrier" refractive index distribution and its optical loss is ~1.02 dB/cm. The microluminescence and absorption investigation reveal that fluorescent and transmission properties in the waveguide are well preserved with respect to the bulk, suggesting promising potential for waveguide amplifiers and lasers. © 2014 Society of Photo-Optical Instrumentation Engineers. (19 refs.)Main Heading: Light propagationControlled terms: Energy dissipation - Erbium - Fluorescence - Glass - Ion implantation - Optical waveguides - Oxygen - Planar waveguides - Refractive index - Silicates - Waveguides - YtterbiumUncontrolled terms: Co-doped silicates - Finite difference beam propagation method - Optical planar waveguides - Refractive index profiles - Refractive-index distribution - Signal amplifications - Transmission property - Waveguide amplifiersClassification Code: 414 Masonry Materials - 525.4 Energy Losses (industrial and residential) - 547.2 Rare Earth Metals - 714.3 Waveguides - 741.1 Light/Optics - 804 Chemical Products Generally - 812 Ceramics, Refractories and Glass - 812.3 Glass - 932.1 High Energy Physics

Database: Compendex

Image super-resolution via saliency sparse representation

Zhang, Xue Jun1, 2; Hu, Bing Liang1 Source: Applied Mechanics and Materials, v 568-570, p 659-662, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.659;

Abstract: The paper proposes a new approach to single-image super resolution (SR), which is based on sparse representation. Previous researchers just focus on the global intensive patch, without local intensive patch. The performance of dictionary trained by the local saliency intensive patch is more significant. Motivated by this, we joined the saliency detection to detect marked area in the image. We proposed a sparse representation for saliency patch of the low-resolution input, and used the coefficients of this representation to generate the high-resolution output. Compared to precious approaches which simply sample a large amount of image patch pairs, the saliency dictionary pair is a more compact representation of the patch pairs, reducing the computational cost substantially. Through the experiment, we demonstrate that our algorithm generates high-resolution images that are competitive or even superior in quality to images produced by other similar SR methods. © (2014) Trans Tech Publications, Switzerland. (16 refs.)Main Heading: Optical resolving powerControlled terms: Materials - MechanicsUncontrolled terms: Compact representation - Computational costs - High resolution image - High-resolution output - Image super-resolution - Saliency detection - Sparse representation - Super resolutionClassification Code: 741.1 Light/Optics - 931.1 Mechanics - 951 Materials Science

Database: Compendex

Corner detection via multi-scale autocorrelation matrix on edge contours

Wang, Hao1, 2; Zhou, Zuo-Feng1; Cao, Jian-Zhong1; Yan, Su1 Source: Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics, v 36, n 6, p 1220-1224, June 2014; Language: Chinese

; ISSN: 1001506X; DOI: 10.3969/j.issn.1001-506X.2014.06.32;

Publisher: Chinese Institute of ElectronicsAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: To reduce the influence of edge tiny changes and noise on the corner detection and improve the detection accuracy, a new corner detection algorithm using multi-scale autocorrelation matrix on edge contours is proposed. Firstly, the edge contour of an image is extracted by an edge detector. Meanwhile, the image is smoothed by the Gaussian kernel function with different scales. For each pixel on the contour, the variation information of gray magnitude on certain scales can be obtained by the differential operator and will be used to construct the autocorrelation matrix. Finally, the normalized eigenvalue of autocorrelation matrices on different scales is defined as the new corner measure. An edge pixel is specified as a corner when its measure is not only above the preset threshold but also the local maximum in a small region. Experimental results show that the proposed algorithm achieves better detection accuracy and fewer false corners. (16 refs.)Main Heading: DetectorsControlled terms: Algorithms - Autocorrelation - Eigenvalues and eigenfunctions - Mathematical operators - PixelsUncontrolled terms: Autocorrelation matrix - Corner detection - Detection accuracy - Differential operators - Edge contour - Gaussian kernel functions - Gaussian kernels - Multi-scale autocorrelationClassification Code: 723.5 Computer Applications - 914 Safety Engineering - 921 Mathematics - 921.1 Algebra

Database: Compendex

Surface waves at the interface between a metal and a photovoltaic- photorefractive crystal

Li, Kehao1; Lu, Keqing2, 4; Zhang, Yiqi3; Hui, Juanli2; Niu, Pingjuan2; Yu, Liyuan2; Zhang, Yanpeng3 Source: Optik, v 125, n 12, p 2974-2977, June 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.12.033;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Department of Electronic Communication Engineering, Henan Mechanical and Electrical Engineering College, Pingyuan Road, Xinxiang 453000, China2 School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin 300387, China3 Key Laboratory for Physical Electronics and Devices, Ministry of Education, Xi'An Jiaotong University, Xi'an 710049, China4 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academic of Sciences, Xi'an 710119, China

Abstract: We investigate surface waves at the interface between a metal and a photovoltaic-photorefractive (PP) crystal. These surface waves appear in several forms: delocalized surface waves, shock surface waves, and localized surface waves. Only localized surface waves have limited energy. We demonstrate that the transverse sizes of localized surface waves decrease with an increase in the propagation constant and the amplitudes of localized surface waves increase with the propagation constant. The stability of localized surface waves is investigated numerically and it is found that they are stable. © 2014 Elsevier GmbH. All rights reserved. (22 refs.)Main Heading: Surface wavesControlled terms: Nonlinear optics - Photoreactivity - Photorefractive crystalsUncontrolled terms: Limited energies - Photorefractive nonlinearity - Photovoltaic - Propagation constant - Shock surfaces - Transverse sizesClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.1.1 Nonlinear Optics - 751 Acoustics, Noise. Sound - 931 Classical Physics; Quantum Theory; Relativity

Database: Compendex

Inscription of waveguides in terbium gallium garnet using femtosecond laser

Long, Xuewen1, 2; Bai, Jing1, 2; Liu, Xin1, 2; Zhao, Wei1; Cheng, Guanghua1 Source: Guangxue Xuebao/Acta Optica Sinica, v 34, n 4, April 2014; Language: Chinese

; ISSN: 02532239; DOI: 10.3788/AOS201434.0432002; Article number: 0432002;

Abstract: Femtosecond-laser-photolithography is a flexible avenue to fabricate three-dimensional photonic devices in transparent materials. Terbium gallium garnet is widely used because of its Faraday rotation. Femtosecond laser operated at 1 kHz with a central wavelength of 800 nm is used to write double line waveguide and circular depressed-cladding waveguide in terbium gallium garnet. The distributions of refractive index change are reconstructed, and propagation losses of the waveguides are measured. Only the double line waveguide shows polarization dependent optical guiding. The magneto-optic response of the waveguides is determined. The rotation of plane of polarization cannot be occurred in double line waveguide under externally applied magnetic field ascribed to the phase mismatch of transvers electric (TE) mode and transverse magnetic (TM) mode. For the circular depressed-cladding waveguide, the plane of polarization is rotated under applied magnetic field. The inscribed double line and circular depressed-cladding waveguide in terbium gallium garnet are candidates for waveguide polarizer and magneto-optic device respectively, which are valuable for integrated optics. (19 refs.)Main Heading: WaveguidesControlled terms: Electric losses - Faraday effect - Gallium - Garnets - Integrated optics - Magnetic fields - Optical waveguides - Photolithography - Polarization - Terbium - Ultrashort pulsesUncontrolled terms: Applied magnetic fields - Femtosecond laser writing - Magneto-optic devices - Refractive index changes - Terbium gallium garnets - Transparent material - Transverse magnetic modes - Waveguide polarizersClassification Code: 547.2 Rare Earth Metals - 549.3 Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals - 606.1 Abrasive Materials - 701.1 Electricity: Basic Concepts and Phenomena - 701.2 Magnetism: Basic Concepts and Phenomena - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 741.3 Optical Devices and Systems - 744.1 Lasers, General

Database: Compendex

Threshold automatic selection hybrid phase unwrapping algorithm for digital holographic microscopy

Zhou, Meiling1; Min, Junwei1; Yao, Baoli1; Yu, Xianghua1; Lei, Ming1; Yan, Shaohui1; Yang, Yanlong1; Dan, Dan1 Source: Journal of Modern Optics, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2014.954649 Article in PressAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Conventional quality-guided (QG) phase unwrapping algorithm is hard to be applied to digital holographic microscopy because of the long execution time. In this paper, we present a threshold automatic selection hybrid phase unwrapping algorithm that combines the existing QG algorithm and the flood-filled (FF) algorithm to solve this problem. The original wrapped phase map is divided into high- and low-quality sub-maps by selecting a threshold automatically, and then the FF and QG unwrapping algorithms are used in each level to unwrap the phase, respectively. The feasibility of the proposed method is proved by experimental results, and the execution speed is shown to be much faster than that of the original QG unwrapping algorithm. © 2014 © 2014 Taylor & Francis.Main Heading: AlgorithmsControlled terms: Microscopic examination - Phase measurementUncontrolled terms: Automatic selection - Digital holographic microscopy - Execution speed - Hybrid phase - Low qualities - Phase unwrapping algorithm - Wrapped phase mapClassification Code: 723 Computer Software, Data Handling and Applications - 746 Imaging Techniques - 921 Mathematics - 942.2 Electric Variables Measurements

Database: Compendex

System contributing to install inside sleeve and filtering algorithm to evaluate its roundness error

Liu, Jie1; Li, Hua1; Chang, Hemin1; Jiang, Xin1 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 6, June 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.0608002; Article number: 0608002;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China

Abstract: Nuclear evaporator has two sleeves, outside sleeve and inside sleeve. To install inside sleeve accurately, the concentricity of the two sleeves and the roundness error of inside sleeve should be evaluated. The system which contributes to install inside sleeve of nuclear evaporator is developed. It is introduced that the parts of the system and the measuring process. The position forms among three close points are divided into three forms: convex, concave and collinear in the data processing. And it is found out how to filter the points that can't fix maximum inscribed circle. Based on that, the filtering algorithm is presented. This algorithm is efficient and easy to be understood. It can save the data processing time. In practical application, the measuring accuracy of the whole system is 0.7 mm, which can meet the needs of project and have practical value. (14 refs.)Main Heading: AlgorithmsControlled terms: Data handling - Evaporators - Measurements - Signal filtering and predictionUncontrolled terms: Filtering algorithm - Inscribed circles - Inside sleeve - Measuring accuracy - Roundness errorClassification Code: 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 731.1 Control Systems - 802.1 Chemical Plants and Equipment - 921 Mathematics - 941 Acoustical and Optical Measuring Instruments - 942 Electric and Electronic Measuring Instruments - 943 Mechanical and Miscellaneous Measuring Instruments - 944 Moisture, Pressure and Temperature, and Radiation Measuring Instruments

Database: Compendex

Fabrication and annealing optimization of oxygen-implanted Yb 3+-doped phosphate glass planar waveguides

Liu, Chun-Xiao1, 2; Xu, Jun3; Li, Wei-Nan2; Xu, Xiao-Li1; Guo, Hai-Tao2; Wei, Wei2, 4; Wu, Gen-Gen1; Hu, Yue1; Peng, Bo2, 4 Source: Optics and Laser Technology, v 63, p 45-49, November 2014

; ISSN: 00303992; DOI: 10.1016/j.optlastec.2014.03.014;

Publisher: Elsevier LtdAuthor affiliation: 1 School of Electronic and Information Engineering, Hefei Normal University, Hefei 230601, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences (CAS), Xi'an 710119, China3 School of Information Engineering, East China Jiaotong University, Nanchang 330013, China4 School of Optoelectronic Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210046, China

Abstract: Optical planar waveguides in Yb3+-doped phosphate glasses are fabricated by (5.0+6.0) MeV O3+ ion implantation at fluences of (4.0+8.0)×1014 ions/cm2. The annealing treatment is carried out to optimize waveguide performances. The prism-coupling and end-face coupling methods are used to measure the dark-mode spectra and near-field intensity distributions before and after annealing at 350 °C for 60 min, respectively. The refractive index profile of the planar waveguide is obtained based on the reflectivity calculation method. The micro-Raman spectrum of the waveguide is in agreement with that of the bulk, exhibiting possible applications for integrated active photonic devices. © 2014 Elsevier Ltd. (18 refs.)Main Heading: YtterbiumControlled terms: Annealing - Glass - Ion implantation - Optimization - Planar waveguides - WaveguidesUncontrolled terms: Active photonic devices - Annealing treatments - Coupling methods - Micro-Raman spectra - Near-field intensity - Optical planar waveguides - Phosphate glass - Refractive index profilesClassification Code: 537.1 Heat Treatment Processes - 547.2 Rare Earth Metals - 714.3 Waveguides - 812.3 Glass - 921.5 Optimization Techniques - 932.1 High Energy Physics

Database: Compendex

Anomaly detection in crowd scene via online learning

Ma, Dandan1, 3; Wang, Qi2; Yuan, Yuan1 Source: ACM International Conference Proceeding Series, p 158-162, 2014, ICIMCS 2014 - Proceedings of the 6th International Conference on Internet Multimedia Computing and Service; ISBN-13: 9781450328104; DOI: 10.1145/2632856.2632862; Conference: 6th International Conference on Internet Multimedia Computing and Service, ICIMCS 2014, July 10, 2014 - July 12, 2014; Sponsor: National Natural Foundation of China; SIGMM China Chapter; Xiamen University;

Abstract: Anomaly detection in crowd scene has attracted an increasing attention in video surveillance, but a precise detection still remains a challenge. This paper presents a novel online learning method to automatically detect abnormal behaviors in crowd scene. Our focus is mainly on the deviation between the real motion and the predicted one. Through on-line defining experts, analyzing their motions, and dynamically updating the learned model, anomaly can be identified by the final expert joint decision. The outputs are represented as the anomaly probability of an examined frame. Compared with most of existing methods, the proposed one needs neither tracking each individual straight to the end nor requires any complex training procedure. We test the proposed method on public datasets, and the results show its effectiveness. Copyright 2014 ACM. (15 refs.)Main Heading: E-learningControlled terms: Behavioral research - Motion estimation - Network security - Security systemsUncontrolled terms: Abnormal behavior - Anomaly detection - Crowd scene - Object Tracking - On-line learning methods - Online learning - Training procedures - Video surveillanceClassification Code: 716.1 Information Theory and Signal Processing - 723 Computer Software, Data Handling and Applications - 914.1 Accidents and Accident Prevention - 971 Social Sciences

Database: Compendex

A method to measure off-axis fabrication and off-axis angle of axis aspheric mirror precisely

Zhang, Xuemin1, 2; Wei, Ruyi1, 2; Yu, Tao1; Hou, Xiaohua1; Duan, Jiayou1; Li, Hua1 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 4, April 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.0416001; Article number: 0416001;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: The alignment method of off-axis three-mirror anastigmat combines initial positioning and computer-aided alignment. During manufacturing, due to the limit of testing methods, the off-axis fabrication and off-axis angle cannot be measured precisely. The initial positioning based on the manufacturing off-axis parameter can bring large initial aberration, which can not be converged when using computer-aided alignment. The optical path is analyzed based on the auto-collimation principle, and the mathematic relationship between the position of off-axis mirror and the reflected image is derived. A system based on the relationship is given to measure the off-axis fabrication and off-axis angle, it includes the right angle plate of high precision, linear guides of high precision, the special center orientation tool, internal focusing telescope and self-standardized micro-flat optical tube. The measurement accuracy of off-axis fabrication and off-axis angle is ±0.05 mm and ±10″ respectively. (12 refs.)Main Heading: FabricationControlled terms: Mirrors - Remote sensing - Testing - ToolsUncontrolled terms: Alignment methods - Computer-aided alignment - Internal focusing telescopes - Measurement accuracy - Off-axis - Off-axis angles - Off-axis aspheric - Three-mirror anastigmatsClassification Code: 423.2 Non Mechanical Properties of Building Materials: Test Methods - 603 Machine Tools - 605 Small Tools and Hardware - 731.1 Control Systems - 741.3 Optical Devices and Systems - 913.4 Manufacturing

Database: Compendex

Large-mode-area infrared guiding in ultrafast laser written waveguides in Sulfur-based chalcogenide glasses

D'Amico, C.1; Cheng, G.1, 2; Mauclair, C.1; Troles, J.3; Calvez, L.3; Nazabal, V.3; Caillaud, C.3; Martin, G.4; Arezki, B.4; LeCoarer, E.4; Kern, P.4; Stoian, R.1 Source: Optics Express, v 22, n 11, p 13091-13101, 41792; E-ISSN: 10944087; DOI: 10.1364/OE.22.013091;

Publisher: Optical Society of AmericaAuthor affiliation: 1 Laboratoire Hubert Curien, UMR 5516 CNRS, Université de Lyon, 42000 St. Etienne, France2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, CAS, 710119 Xi'an Shaanxi, China3 Chemical Sciences Institute of Rennes, UMR 6226 CNRS, University of Rennes i, 35042 Rennes, France4 Institut de Planetologie et D'Astrophysique de Grenoble, UMR 5274 CNRS, Université Joseph Fourier, 38041 Grenoble, France

Abstract: Current demands in astrophotonics impose advancing optical functions in infrared domains within embedded refractive index designs. We demonstrate concepts for large-mode-area guiding in ultrafast laser photowritten waveguides in bulk Sulfur-based chalcogenide glasses. If positive index contrasts are weak in As<inf>2</inf>S<inf>3</inf>, Ge doping increases the matrix rigidity and allows for high contrast (10?3) positive refractive index changes. Guiding with variable mode diameter and large-mode-area light transport is demonstrated up to 10μm spectral domain using transverse slit-shaped and evanescently-coupled multicore traces. © 2014 Optical Society of America. (53 refs.)Main Heading: WaveguidesControlled terms: Chalcogenides - Germanium - Glass - Refractive index - Sulfur - Ultrafast lasersUncontrolled terms: Chalcogenide glass - Current demands - Infrared domains - Light transport - Matrix rigidity - Optical function - Refractive index changes - Spectral domainsClassification Code: 714.3 Waveguides - 741.1 Light/Optics - 744.1 Lasers, General - 804 Chemical Products Generally - 812.3 Glass

Database: Compendex

Aberration athermal design for infrared search and trace optical system

Shen, Mande1; Jiang, Qinxiu1; Li, Cheng1; Ren, Huanhuan1; Chen, Liangyi2 Source: Optik, v 125, n 14, p 3603-3605, July 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.01.076;

Abstract: To satisfy environment requirement of infrared search and trace optical system, an infrared diffractive/refractive hybrid optical system in 3.7-4.8 μm with 11.42°of field of view for passive athermalization is presented. The system is consisted of three lenses, including two aspheric surfaces and a diffraction surface, which has only two materials Ge and Si. The optical system has compact structure, small volume and light weight. The image quality of the system approaches the diffraction limit in the temperature range -80 °C to 160°C. It is compatible with staring focal plane array which has a format of 320 × 240 and the pixel pitch of 30 μm. The system need not move the compensated lens repeatedly to obtain the best images from -80°C to 160°C and enhances the performance of target tracking and recognition. © 2014 Elsevier GmbH. All rights reserved.Main Heading: Optical systemsControlled terms: Diffraction - Diffractive optics - Germanium - Optical design - Target trackingUncontrolled terms: Aspheric surfaces - Athermal designs - Compact structures - Diffraction limits - Hybrid optical systems - Infrared optical systems - Passive athermalization - Temperature rangeClassification Code: 716.2 Radar Systems and Equipment - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 804 Chemical Products Generally

Database: Compendex

Passively Q-switched Nd:YAG laser with graphene oxide in heavy water

Wen, Qiao1, 2; Zhang, Xiaojun1, 2; Wang, Yonggang1, 3; Wang, Yishan3; Niu, Hanben1 Source: IEEE Photonics Journal, v 6, n 2, p 1-6, April 2014

; ISSN: 19430655; DOI: 10.1109/JPHOT.2014.2309631; Article number: 6755494;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China2 Key Laboratory of Micro-Nano Measuring and Imaging in Biomedical Optics, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Liquid saturable absorbers have some advantages in some aspects over solid saturable absorbers. In this paper, graphene oxide in heavy water (deuteroxide, D2O) dispersion was fabricated and used as absorber in Q-switched Nd:YAG laser for the first time, to the best of our knowledge. The shortest pulse width of the Q-switched laser is 523 ns, corresponding to a repetition rate of 92.9 kHz. The maximum peak power of Q-switched pulse is 6.6 W. Such a liquid absorber has the virtues of good optical transparency, high heat dissipation, and no contact damage. © 2014 IEEE. (19 refs.)Main Heading: Neodymium lasersControlled terms: Graphene - Heavy water - Lasers - Q switching - Saturable absorbersUncontrolled terms: Graphene oxides - Non-linear optical material - Optical transparency - Passively Q-switched - Pulsewidths - Q switched Nd:YAG laser - Q-switched pulse - Repetition rateClassification Code: 744 Lasers - 804 Chemical Products Generally

Database: Compendex

Exposure fusion using boosting Laplacian pyramid

Shen, Jianbing1; Zhao, Ying1; Yan, Shuicheng2; Li, Xuelong3 Source: IEEE Transactions on Cybernetics, v 44, n 9, p 1579-1590, September 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2290435; Article number: 6674110;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Beijing Key Laboratory of Intelligent Information Technology, School of Computer Science, Beijing Institute of Technology, Beijing 100081, China2 Department of Electrical and Computer Engineering, National University of Singapore, Singapore3 State Key Laboratory of Transient Optics and Photonics, Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, Shaanxi, China

Abstract: This paper proposes a new exposure fusion approach for producing a high quality image result from multiple exposure images. Based on the local weight and global weight by considering the exposure quality measurement between different exposure images, and the just noticeable distortion-based saliency weight, a novel hybrid exposure weight measurement is developed. This new hybrid weight is guided not only by a single image's exposure level but also by the relative exposure level between different exposure images. The core of the approach is our novel boosting Laplacian pyramid, which is based on the structure of boosting the detail and base signal, respectively, and the boosting process is guided by the proposed exposure weight. Our approach can effectively blend the multiple exposure images for static scenes while preserving both color appearance and texture structure. Our experimental results demonstrate that the proposed approach successfully produces visually pleasing exposure fusion images with better color appearance and more texture details than the existing exposure fusion techniques and tone mapping operators. © 2013 IEEE. (37 refs.)Main Heading: Laplace transformsControlled terms: Textures - WeighingUncontrolled terms: Exposure fusions - global and local exposure weight - Gradient vectors - High quality images - Laplacian Pyramid - Quality measurements - Texture structure - Tone mapping operatorsClassification Code: 921.3 Mathematical Transformations - 933 Solid State Physics - 943.3 Special Purpose Instruments

Database: Compendex

Selective plane illumination microscopy with structured illumination based on spatial light modulators

Li, Runze1; Zhou, Xing1; Wu, Di1; Peng, Tong1; Yang, Yanlong1; Lei, Ming1; Yu, Xianhua1; Yao, Baoli1; Ye, Tong2 Source: Progress in Biomedical Optics and Imaging - Proceedings of SPIE, v 8949, 2014, Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXI

; ISSN: 16057422; ISBN-13: 9780819498625; DOI: 10.1117/12.2040319; Article number: 89491S; Conference: Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XXI, February 3, 2014 - February 6, 2014; Sponsor: The Society of Photo-Optical Instrumentation Engineers (SPIE);

Abstract: Structured-illumination microscopy (SIM) is an efficacious tool to decrease the contribution of the out-of-focus light to images of specimens. However, in SIM, the frequency of the spatial modulation applied to specimens should be adjustable according to the optical properties of the specimens to reach the optimal contrasts. Hence, a common theme in SIM is how the flexibility and quality of modulations at different frequencies can be improved. Digital scanned laser light-sheet microscopy with structured illumination (DSLM-SI) has been the most flexible means for generating modulation and optical sectioning. The complexity of synchronization between the temporal modulation and the beam scanning makes it hard to use and less stable; it also takes more time to acquire images for one plane than selective plane illumination microscopy (SPIM). In this report, we present a recent effort to use a spatial light modulator (SLM) to provide spatial modulation in SPIM. With the SLM, both of the frequency and phase of lateral modulation can be changed rapidly; moreover, this SLM-based SPIM can achieve fast imaging without mechanical moving parts. © 2014 SPIE. (8 refs.)Main Heading: Light modulatorsControlled terms: Image acquisition - Light modulation - Three dimensionalUncontrolled terms: Digital scanned laser light-sheet - Light-sheet - Light-sheet microscopies - Mechanical moving parts - Selective plane illuminations - Spatial light modulators - Structured-illumination - Temporal modulationsClassification Code: 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Re-texturing by intrinsic video

Shen, Jianbing1; Yan, Xing1; Chen, Lin1; Sun, Hanqiu2; Li, Xuelong3 Source: Information Sciences, v 281, p 726-735, October 10, 2014

; ISSN: 00200255; DOI: 10.1016/j.ins.2014.02.134;

Publisher: Elsevier Inc.Author affiliation: 1 Beijing Lab of Intelligent Information Technology, School of Computer Science, Beijing Institute of Technology, Beijing 100081, China2 Department of Computer Science and Engineering, Chinese University of Hong Kong, Shatin, NT, Hong Kong3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: In this paper, we present a novel re-texturing approach using intrinsic video. Our approach first indicates the regions of interest by contour-aware layer segmentation. The intrinsic video including reflectance and illumination components within the segmented region is recovered by our weighted energy optimization. We then compute the texture coordinates in key frames and the normals for the re-textured region using the optimization approach we develop. Meanwhile, the texture coordinates in non-key frames are optimized by our energy function. When the target sample texture is specified, the re-textured video is finally created by multiplying the re-textured reflectance component with the original illumination component within the replaced region. As shown in our experimental results, our method can produce high quality video re-texturing results with a variety of sample textures, and also the lighting and shading effects of the original videos are well preserved after re-texturing. © 2014 Elsevier Inc. All rights reserved. (28 refs.)Main Heading: TexturesControlled terms: ReflectionUncontrolled terms: Energy optimization - Illumination components - Intrinsic video - Optimization approach - Re-texturing - Reflectance components - Regions of interest - Texture coordinatesClassification Code: 711 Electromagnetic Waves - 933 Solid State Physics

Database: Compendex

Relative intensity noise characteristic of broadband sources and its effect on performance of closed-loop fiber optic gyroscope

Suo, Xinxin1; Yang, Yuanhong1, 2; Yang, Mingwei1; Ma, Haiquan3; Zhang, Bin3 Source: Zhongguo Jiguang/Chinese Journal of Lasers, v 41, n 6, June 2014; Language: Chinese

; ISSN: 02587025; DOI: 10.3788/CJL201441.0605009; Article number: 0605009;

Publisher: Science PressAuthor affiliation: 1 Key Laboratory on Precision Opto-Mechatronics Technology of Ministry of Education, Beihang University, Beijing 100191, China2 National Key Laboratory on Inertial Technology, Beihang University, Beijing 100191, China3 AVIC Xi'an Flight Automatic Control Research Institute, Xi'an, Shaanxi 710065, China

Abstract: The accurate evaluation of relative intensity noise (RIN) of broad-band sources and its effect mechanism on a fiber optic gyroscope (FOG) are key factors to further improve the performance of FOGs. An intensity noise measurement system is constructed and RINs of four sources with different spectral shapes and degree of polarizations are tested. Then the RINs are calculated with three different effective bandwidths and the accurate RIN model is confirmed by employing the power weighted average (PWA) bandwidth. Based on this research, the random walk coefficient (RWC) model of FOG is modified. A photoelectric detachment high precision FOG is constructed, and the RWC of FOG is tested with four broadband sources and calculated by using the modified model. It is shown that the calculation results are consistent with the experiment results. This indicates that the power weighted average bandwidth and the degree of polarization are key factors determining the RIN of broadband sources and this research is of great value in evaluating the RIN characteristics of different sources and designing high performance FOGs. (18 refs.)Main Heading: Fiber opticsControlled terms: Bandwidth - Gyroscopes - Polarization - Random processes - Statistical methodsUncontrolled terms: Broadband sources - Calculation results - Degree of polarization - Effective bandwidth - Fiber optic gyroscopes - Random walk coefficients - Relative intensity noise - Weighted averagesClassification Code: 716.1 Information Theory and Signal Processing - 741.1 Light/Optics - 741.1.2 Fiber Optics - 922.1 Probability Theory - 922.2 Mathematical Statistics - 943.1 Mechanical Instruments

Database: Compendex

Observation of multipulse bunches in a graphene oxide passively mode-locked ytterbium-doped fiber laser with all-normal dispersion

Huang, Shisheng1; Wang, Yonggang2; Peiguang, Yan1; Zhang, Gelin1; Zhao, Junqing1; Li, Huiquan1; Lin, Rongyong1; Cao, Guangzhong3; Duan, Ji'An4 Source: Applied Physics B: Lasers and Optics, v 116, n 4, p 939-946, September 2014

; ISSN: 09462171; DOI: 10.1007/s00340-014-5780-7;

Publisher: Springer VerlagAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, College of Electronic Science and Technology, Shenzhen University, Shenzhen 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Shenzhen Key Laboratory of Electromagnetic Control, Shenzhen University, Shenzhen 518060 Guangdong, China4 State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083 Hunan, China

Abstract: We give a systematic experimental study of multipulse bunches in a graphene oxide saturable absorber (GOSA) passively mode-locked all-normal dispersion ytterbium-doped fiber laser (YDFL). Some special phenomena such as harmonic multipulse bunches, harmonic mode-locking, and chaotic multipulse states are also obtained. Our experiment reveals that the inserted 2.5-nm narrow bandwidth filter plays an important role in the formation of multipulse in all-normal dispersion fiber lasers. Because of the effective gain bandwidth depends on both the 2.5-nm narrow bandwidth filter and the artificial fiber birefringence filter, the multipulse operation states are sensitive to the polarization. It is the first demonstration of multipulse evolution in a GOSA passively mode-locked all-normal dispersion YDFL. © 2014 Springer-Verlag Berlin Heidelberg. (39 refs.)Main Heading: Locks (fasteners)Controlled terms: Fiber lasers - Graphene - Passive mode locking - Saturable absorbers - YtterbiumUncontrolled terms: All-normal dispersions - Fiber birefringence - Graphene oxides - Harmonic mode locking - Narrow bandwidth - Operation state - Passively mode-locked - Ytterbium-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Image super-resolution using multi-layer support vector regression

Xu, Jie1; Deng, Cheng1; Gao, Xinbo1; Tao, Dacheng2; Li, Xuelong3 Source: ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings, p 5799-5803, 2014, 2014 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2014

; ISSN: 15206149; ISBN-13: 9781479928927; DOI: 10.1109/ICASSP.2014.6854715; Article number: 6854715; Conference: 2014 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2014, May 4, 2014 - May 9, 2014;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic Engineering, Xidian University, Xi'an 710071, China2 Centre for Quantum Computation and Intelligent Systems, University of Technology, Sydney, Australia3 Xi'An Institute of Optics and Precision Mechanics, CAS, Xi'an 710119, China

Abstract: Existing support vector regression (SVR) based image superresolution (SR) methods always utilize single layer SVR model to reconstruct source image, which are incapable of restoring the details and reduce the reconstruction quality. In this paper, we present a novel image SR approach, where a multi-layer SVR model is adopted to describe the relationship between the low resolution (LR) image patches and the corresponding high resolution (HR) ones. Besides, considering the diverse content in the image, we introduce pixel-wise classification to divide pixels into different classes, such as horizontal edges, vertical edges and smooth areas, which is more conductive to highlight the local characteristics of the image. Moreover, the input elements to each SVR model are weighted respectively according to their corresponding output pixel's space positions in the HR image. Experimental results show that, compared with several other learning-based SR algorithms, our method gains high-quality performance. © 2014 IEEE. (11 refs.)Main Heading: PixelsControlled terms: Multilayers - Optical resolving power - Regression analysis - Signal processingUncontrolled terms: Different class - Horizontal edge - Image super-resolution - Local characteristics - Low resolution images - Reconstruction quality - Superresolution - Support vector regression (SVR)Classification Code: 716.1 Information Theory and Signal Processing - 723.5 Computer Applications - 741.1 Light/Optics - 922.2 Mathematical Statistics - 933.1 Crystalline Solids

Database: Compendex

A new type laser imaging system of underwater wake bubbles

Xi-Zhan, Liu1; Yan-Bo, Xue1 Source: Applied Mechanics and Materials, v 543-547, p 2505-2508, 2014, Vehicle, Mechatronics and Information Technologies II

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350606; DOI: 10.4028/www.scientific.net/AMM.543-547.2505; Conference: International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2014, February 19, 2014 - February 20, 2014; Sponsor: INTIEA Information and Engineering; Scientific.Net; Trans Tech publications inc.; National Institute of Technology Rourkela; Universitatea Politehnica Din Bucuresti; et al;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an 710119, China

Abstract: Considering the difficulties in the wake bubbles imaging, a wake bubbles measurement system was presented based on the combination of high speed photography and laser sheet scanning technology. In this system, laser sheet was used to illuminate the wake zone to avoid the image stacking of bubbles. Because the particle size of bubbles was in a wide range(10~500um), three switchable magnification lenses were designed for the bubbles imaging. the test results show that th image quality is good and this system satisfies technical requirements. © (2014) Trans Tech Publications, Switzerland. (6 refs.)Main Heading: WakesControlled terms: Bubbles (in fluids) - High speed photography - Information technologyUncontrolled terms: Image stacking - Laser imaging system - Laser sheets - Measurement system - Switchable - Technical requirement - Underwater - Wake bubbleClassification Code: 631.1 Fluid Flow, General - 742.1 Photography - 903 Information Science - 931.1 Mechanics

Database: Compendex

Efficient optical Kerr gating property of fluorotellurite glass

Xiong, Yaobing1; Yan, Lihe1, 2; Zhou, Zhiguang2; Yi, Wenhui1; Lin, Aoxiang2; Si, Jinhai1; Chen, Feng1; Hou, Xun1 Source: Optik, v 125, n 3, p 1444-1447, February 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2013.09.016;

Publisher: Urban und Fischer Verlag JenaAuthor affiliation: 1 Key Lab. for Phys. Electronics and Devices of the Min. of Educ., School of Electronic and Information Engineering, Xi'An Jiaotong University, Xi'an 710049, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Xi'an 710119, China

Abstract: We investigated the ultrafast optical Kerr effect of the fluorotellurite glass (Ft glass), the nonlinear response time of which was measured to be less than 230 fs, while the nonlinear refractive index was estimated to be 9.62 × 10-16 cm2/W. Using optical Kerr gate (OKG) technique with Ft glass as Kerr medium, we obtained narrow-bandwidth and symmetric gated spectra from a supercontinuum (SC) generated by a femtosecond laser. Experimental results indicated that Ft glass was a good candidate for an OKG medium due to its fast response time, large nonlinearity, and high transparency. © 2013 Elsevier GmbH. (21 refs.)Main Heading: GlassControlled terms: Optical Kerr effect - Refractive indexUncontrolled terms: Fast response time - Fluoro-tellurite glass - High transparency - Nonlinear refractive index - Nonlinear response time - Optical Kerr gate - Super continuum - Ultrafast optical Kerr effectsClassification Code: 741.1 Light/Optics - 812.3 Glass

Database: Compendex

Theoretical analysis and the morphology control of vertical phase segregation in high-efficiency polymer/fullerene solar cells

Gao, Bowen1, 2 Source: High Performance Polymers, v 26, n 2, p 197-204, March 2014

; ISSN: 09540083, E-ISSN: 13616412; DOI: 10.1177/0954008313506725;

Publisher: SAGE Publications LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an Shaanxi 710119, China2 School of Electronics and Information Engineering, Xi'An Jiaotong University, Xi'an, China

Abstract: The morphology control and optimization in the film-forming process and nanoscale phase separation of donor/acceptor interpenetrating networks played an important role in improving the performance of organic solar cells. Vertical phase separation was defined as an inhomogeneous distribution or concentration gradient of polymer/fullerene blends in the spin-coated film, due to the surface energy of the respective components and their interaction with the substrate or the intermediate buffer layers. In this report, we demonstrated, in detail, the theory of vertical phase separation morphology and control of conventional structure solar cells and inverted configuration solar cells, including the choice of solvents and the drying rate, the surface energy control, thermal annealing, as well as external electric field. In particular, we first proposed internal electronic field model of vertical phase separation and revealed the internal rules and organic semiconductor physics and its mechanism for improving the device efficiency and stability. © The Author(s) 2013. (12 refs.)Main Heading: Solar cellsControlled terms: Heterojunctions - Interfacial energy - Morphology - Phase separationUncontrolled terms: Bulk heterojunction - Concentration gradients - Conventional structures - Inhomogeneous distribution - Nano-scale phase separation - Organic semiconductor physics - Organic solar cell - Vertical phase separationsClassification Code: 615.2 Solar Power - 641.1 Thermodynamics - 714.2 Semiconductor Devices and Integrated Circuits - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

Theoretical and static experiment research on all optical solid state streak camera

Liang, Ling-Liang1, 2, 3; Tian, Jin-Shou1; Wang, Tao1; Li, Fu-Li3; Gao, Gui-Long1, 2, 3; Wang, Jun-Feng1; Wang, Chao1; Lu, Yu1; Xu, Xiang-Yan1; Cao, Xi-Bin1; Wen, Wen-Long1; Xin, Li-Wei1; Liu, Hu-Lin1; Wang, Xing1 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 6, March 20, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.060702; Article number: 060702;

Publisher: Institute of Physics, Chinese Academy of SciencesAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Xi'an 710119, China2 Graduate University of Chinese Academy of Sciences, Beijing 100039, China3 Science College, Xi'an Transportation University, Xi'an 710049, China

Abstract: All optical solid state streak camera is to carry out the process of deflecting and scanning of the signal light which is coupled into the core of the waveguide, with spatially-modulated pump pulse exciting the light deflector, through precisely controlling the time delay between signal light and pump light. Not only can it solve the problems existing in the traditional photoelectron streak camera such as the decrease of the dynamic range caused by space charge effect and incapability of detecting the infrared light signal for photoelectric cathode, but also it has the advantages of simple structure, systemic stability. And the theoretical temporal resolution can reach up to picosecond scale even sub picosecond scale. For the Al<inf>x</inf>Ga<inf>1-x</inf>As/GaAs/ Al<inf>x</inf>Ga<inf>1-x</inf>As planar waveguide light deflector, we discuss in detail the change of the refractive index of the GaAs with time under the common influences of band filling, band gap shrinkage and free carrier absorption effect; when the change of the refractive index is on the order of 0.01 and the ratio of the signal spot size to the width of the waveguide p = 0.5, the theoretical temporal resolution can reach 2 ps; finally, the theoretical spatial resolution is calculated to be 17 lp/mm according to the condition of static experiment, while the experimental results show that spatial resolution is 9 lp/mm. © 2014 Chinese Physical Society. (15 refs.)Main Heading: ExperimentsControlled terms: Gallium - Image resolution - Optical instruments - Optical pumping - Optics - Refractive index - Streak cameras - WaveguidesUncontrolled terms: All optical - Free carrier absorption - Light deflectors - Simple structures - Space charge effects - Spatial resolution - Static experiments - Temporal resolutionClassification Code: 549.3 Nonferrous Metals and Alloys excluding Alkali and Alkaline Earth Metals - 714.3 Waveguides - 741 Light, Optics and Optical Devices - 742 Cameras and Photography - 742.2 Photographic Equipment - 901.3 Engineering Research

Database: Compendex

A multispectral image fusion algorithm based on the HIS space and improved wavelet

Duan, Zewei1, 2; Wen, Desheng1; Song, Zongxi1 Source: Journal of Information and Computational Science, v 11, n 6, p 1869-1878, April 10, 2014

; ISSN: 15487741; DOI: 10.12733/jics20103220;

Publisher: Binary Information PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: In order to optimize the multispectral image fusion, the paper proposes a fusion method based on HIS space and improved wavelet. The new method maps the multispectral image to HIS space and acquires components of intensity, hue and saturation. In addition, an improved wavelet algorithm is applied on the fusion of the intensity of multispectral image and the panchromatic image, the algorithm can both consider the fusion method of low-frequency and high-frequency sub-bands: On the low-frequency subband aspect, the paper introduces a border detector operator in order to collect the border information of images that can be the basis of selective fusion method; On the high-frequency sub-band aspect, it applies local-standard-deviation to be the basis of selective and weighted-averaging fusion method. Ultimately, the new HIS components obtain fusion result through reverse transformation. The experiment reveals that the result acquired by this method can improve on the quality of spectral information and spatial information. © 2014 Binary Information Press. (12 refs.)Main Heading: Image fusionControlled terms: AlgorithmsUncontrolled terms: Border information - HIS space - Improved wavelet - Local-standard-deviation - Multi-spectral image fusionsClassification Code: 723 Computer Software, Data Handling and Applications - 723.2 Data Processing and Image Processing - 921 Mathematics

Database: Compendex

Watt-level Q-switched Nd:LuVO <inf>4</inf> laser based on a graphene oxide saturable absorber

Yan, Shilian1; Zhang, Ling1; Yu, Haijuan1; Sun, Wei1; Li, Menglong1; Hou, Wei1; Lin, Xuechun1; Wang, Yonggang2; Wang, Yishan2 Source: Journal of Modern Optics, v 61, n 3, p 234-238, February 6, 2014

; ISSN: 09500340, E-ISSN: 13623044; DOI: 10.1080/09500340.2013.879935;

Publisher: Taylor and Francis Ltd.Author affiliation: 1 Laboratory of All-solid-state Light Sources, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China2 State Key Laboratory of Transient Optics and Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xian 710119, China

Abstract: The demonstration is reported of a diode-pumped passively Q-switched Nd:LuVO4 laser at 1064 nm using a transmission-type graphene oxide as the saturable absorber. The graphene oxide saturable absorber with a modulation depth of 10% was fabricated using a vertical evaporation method. With a pump of 11.5 W, a maximum output power of 1.353 W was obtained with 186-ns pulse duration and 336.7-kHz repetition rate, corresponding to a maximum pulse energy of 4 J per pulse. © 2014 © 2014 Taylor & Francis. (18 refs.)Main Heading: Saturable absorbersControlled terms: Graphene - Optical pumping - Q switchingUncontrolled terms: End-pumped lasers - Evaporation method - Graphene oxides - Maximum output power - Modulation depth - Passively Q-switched - Pulse durations - Repetition rateClassification Code: 741.1 Light/Optics - 744.1 Lasers, General - 744.8 Laser Beam Interactions - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Tag-Saliency: Combining bottom-up and top-down information for saliency detection

Zhu, Guokang1, 2; Wang, Qi1; Yuan, Yuan1 Source: Computer Vision and Image Understanding, v 118, p 40-49, January 2014

; ISSN: 10773142, E-ISSN: 1090235X; DOI: 10.1016/j.cviu.2013.07.011;

Publisher: Academic Press Inc.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China2 School of Electronic and Information Engineering, Xi'An Jiaotong University, Xi'an 710049, Shaanxi, China

Abstract: In the real world, people often have a habit tending to pay more attention to some things usually noteworthy, while ignore others. This phenomenon is associated with the top-down attention. Modeling this kind of attention has recently raised many interests in computer vision due to a wide range of practical applications. Majority of the existing models are based on eye-tracking or object detection. However, these methods may not apply to practical situations, because the eye movement data cannot be always recorded or there may be inscrutable objects to be handled in large-scale data sets. This paper proposes a Tag-Saliency model based on hierarchical image over-segmentation and auto-tagging, which can efficiently extract semantic information from large scale visual media data. Experimental results on a very challenging data set show that, the proposed Tag-Saliency model has the ability to locate the truly salient regions in a greater probability than other competitors. © 2013 Elsevier Inc. All rights reserved. (57 refs.)Main Heading: Behavioral researchControlled terms: Computer vision - Eye movements - SemanticsUncontrolled terms: Bottom-up and top-down - Eye movement datum - Image over segmentations - Image tagging - Saliency detection - Semantic information - Visual Attention - Visual mediaClassification Code: 461.1 Biomedical Engineering - 723.5 Computer Applications - 903.2 Information Dissemination - 971 Social Sciences

Database: Compendex

A Study on the technical method of drilling micro holes on new CMC-SiC with femtosecond laser

Feng, Wang1, 2; Luo, Jian Jun1; Li, Ming2; Deng, Yue2 Source: Applied Mechanics and Materials, v 543-547, p 3924-3930, 2014, Vehicle, Mechatronics and Information Technologies II

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350606; DOI: 10.4028/www.scientific.net/AMM.543-547.3924; Conference: International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2014, February 19, 2014 - February 20, 2014; Sponsor: INTIEA Information and Engineering; Scientific.Net; Trans Tech publications inc.; National Institute of Technology Rourkela; Universitatea Politehnica Din Bucuresti; et al;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 School of Astronautics, Northwestern Polytechnical University, Xi'an 710072, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an 710119, China

Abstract: To solve the difficulties of processing micro holes on the CMC-SiC, femtosecond laser was used as the drilling tool in this paper. And a new type of laser beam scanning module was studied. The study confirms the feasibility of finishing the processing of micro holes whose diameter is less than 2mm on the new CMC-SiC. And the preliminary optimization of processing parameters is completed. According to the experimental results, the important factors affecting the quality of the micro holes were analyzed, and the factors are the processing power and the scanning speed. The results also show that the femtosecond laser processing technology can solve the difficulties of drilling mirco holes on the new CMC-SiC in our country's aerospace field. © (2014) Trans Tech Publications, Switzerland. (8 refs.)Main Heading: Silicon carbideControlled terms: Finishing - Information technology - Ultrashort pulsesUncontrolled terms: CMC-SiC - Femtosecond laser processing - Laser beam scanning - Laser process - Micro holes - Optimization of processing parameters - Processing power - TaperClassification Code: 744.1 Lasers, General - 804.2 Inorganic Compounds - 813.1 Coating Techniques - 903 Information Science

Database: Compendex

Optical system design of multi-spectral camera for space debris

Wang, Hu1, 2; Luo, Jianjun1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 4, p 1188-1193, April 2014; Language: Chinese

; ISSN: 10072276;

Abstract: In order to detect the Space debris, a multi-spectral camera for Space debris was proposed. The multi-spectral camera was consisted of visible camera, long-wave infrared (LWIR) camera and mid- wave infrared (MWIR) camera. Three cameras used the primary mirror and secondary mirror together, including correction lens in every camera in order to balance aberration. The focal length was 1000 mm and field of view was 1.2° for visible camera, and the focal length was 250 mm and field of view was 2.75° for LWIR camera, and the focal length was 500 mm and field of view was 1.38° for MWIR camera. Some measures were taken to make sure the less degradation of MTF for thermal distortion, such as a kind of material with good thermal property as mirror substrate to reduce surface distortion. The modulation transfer function(MTF) of three cameras in condition of 20±5°C was analyzed, which showed a good result for user's requirement. (10 refs.)Main Heading: CamerasControlled terms: Infrared radiation - Manned space flight - Mirrors - Space debrisUncontrolled terms: Degradation of mtf - Longwave infrared - Mirror substrate - Multi-spectral cameras - Rendezvous and docking - Secondary mirror - Surface distortion - Thermal distortionsClassification Code: 656.1 Space Flight - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 742.2 Photographic Equipment

Database: Compendex

Graded index microstructured polymer fiber for terahertz applications

Ma, Tian1, 2; Skorobogatiy, Maksim1; Wang, Lili2 Source: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz, November 13, 2014

; ISSN: 21622027, E-ISSN: 21622035; ISBN-13: 9781479938773; DOI: 10.1109/IRMMW-THz.2014.6955999; Article number: 6955999; Conference: 39th International Conference on Infrared, Millimeter and Terahertz Waves, IRMMW-THz 2014, September 14, 2014 - September 19, 2014; Sponsor: BRUKER; et al.; Gentec; THORLABS; Toptica Photonics; TYDEX;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 École Polytechnique de Montréal, Montreal; QC, Canada2 Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, Shannxi, China

Abstract: A novel graded index microstructured polymer THz fiber, whose graded index profile is achieved by a hexagonal subwavelength air-hole array with graded diameters, is studied. The simulation results show that this geometry design can reduce the dispersion and the confinement loss significantly. © 2014 IEEE. (5 refs.)Main Heading: Terahertz wavesUncontrolled terms: Air-hole arrays - Confinement loss - Geometry designs - Graded index - Polymer fiber - Sub-wavelength - Terahertz applicationsClassification Code: 711 Electromagnetic Waves

Database: Compendex

Study of the guided mode confinement width of the surface plasmon polariton waveguides

Rao, Ruijian1, 2 Source: Optoelectronic Devices and Integration, OEDI 2014, June 18, 2014

; ISBN-10: 1557522774; Conference: Optoelectronic Devices and Integration, OEDI 2014, June 18, 2014 - June 21, 2014; Sponsor: OSA;

Abstract: we propose the mode confinement width on power distribution proportion (CWPDP) about the surface plasmon polariton (SPP) waveguide. By investigating, it is indicated that the CWPDP is more reliable than the full width at half maximum. © OSA 2014. (5 refs.)Main Heading: Surface plasmon resonanceControlled terms: Electromagnetic wave polarization - Optoelectronic devices - Phonons - Photons - Plasmons - Quantum theory - WaveguidesUncontrolled terms: Guided modes - Power distributions - Surface plasmon polaritons - Surface plasmon-polariton waveguidesClassification Code: 711 Electromagnetic Waves - 714.2 Semiconductor Devices and Integrated Circuits - 714.3 Waveguides - 931.3 Atomic and Molecular Physics - 931.4 Quantum Theory; Quantum Mechanics

Database: Compendex

Lightweight design of the rectangular mirror using topology optimization

Xiang, Meng1, 2; Li, Fu1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9280, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413557; DOI: 10.1117/12.2067871; Article number: 928010; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: That minimizing the mass of space optical remote sensor at the same time guaranteeing of structural rigidity and surface shape accuracy, became a new critical research topic. This paper achieves detailed design of meniscus rectangular lens body structure by taking the choice of materials, design of supporting structure and lightweight form of mirror into account. And we established lightweight concrete of the mirror under self-weight by the method of topological optimization design. For the optimization, we used a 3-D model of the rectangular mirror and calculated based on that making minimum weight of the mirror as an objective function constrained by the displacement of the mirror surface. Finally finite element analysis method was adopted to get the optimization results analyzed and compared with the traditional triangular lightweight model. Analysis results prove that: the new mirror is superior to the traditional model in surface accuracy and structural rigidity, PV value, RMS value and the lightweight rate. With enough high dynamic-static stiffness and thermal stability, this kind of mirror can meet the demand under the self-weight and the random vibration environment respectively. So this article puts forward a new idea in the lightweight design of rectangular mirror. © 2014 SPIE. (10 refs.)Main Heading: Structural designControlled terms: Constrained optimization - Design - Finite element method - Light weight concrete - Manufacture - Mirrors - Optical testing - Rigidity - Shape optimization - Telescopes - TopologyUncontrolled terms: Critical researches - Finite element analysis method - Lightweight design - Objective functions - Space optical remote sensor - Structural rigidity - Supporting structure - Topological optimizationClassification Code: 408 Structural Design - 408.1 Structural Design, General - 412 Concrete - 537.1 Heat Treatment Processes - 741.3 Optical Devices and Systems - 921 Mathematics - 951 Materials Science - 961 Systems Science

Database: Compendex

The preset grating effect for mutually pumped phase conjugator

Ma, Lin1; Kang, Zhihua2; Zhang, Ninghua2; Liu, Jifang2; Shi, Shunxiang2 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9269, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413427; DOI: 10.1117/12.2071924; Article number: 92691H; Conference: Quantum and Nonlinear Optics III, October 9, 2014 - October 11, 2014; Sponsor: Chinese Optical Society (COS); The Society of Photo-Optical Instrumentation Engineers (SPIE);

Publisher: SPIEAuthor affiliation: 1 School of Physics and Optoelectronic Engineering, Xidian University, Xi'an Shaanxi, China2 State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an Shaanxi, China

Abstract: Based on the four-wave mixing mechanism and light fanning effect, a mutually pumped phase conjugator(MPPC) model is proposed to analyze the variation of MPPC output response with time for different scattering seed value. It shows that preset grating can enhance the fan light intensity when it satisfies Bragg condition and also can shorten MPPC response time. In experiment the bird-wings MPPC is done with or without the preset grating and the variation of MPPC reflectivity with time is obtained in two cases, and simulation conclusion is in agreement with the experimental result. These results have importance for applications of MPPC on optical heterodyne detection. © 2014 SPIE. (11 refs.)Main Heading: Four wave mixingControlled terms: Light - Nonlinear opticsUncontrolled terms: Bragg conditions - Light intensity - Mutually pumped phase conjuator(MPPC) - Mutually pumped phase conjugators - Optical heterodyne detections - Output response - Photo-refractive - Preset gratingClassification Code: 741.1 Light/Optics - 741.1.1 Nonlinear Optics

Database: Compendex

Imaging of large-area microchannel plates using phosphor screens

Wang, X.1, 2; Setru, S.U.1; Xie, J.1; Mane, A.1; Demarteau, M.1; Wagner, R.1 Source: Journal of Instrumentation, v 9, n 11, November 1, 2014; E-ISSN: 17480221; DOI: 10.1088/1748-0221/9/11/P11011; Article number: P11011;

Publisher: Institute of Physics PublishingAuthor affiliation: 1 Argonne National Laboratory, 9700 S Cass Ave., Argonne; IL, United States2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, NO.17 Xinxi Road, Xi'an, Shaanxi, China

Abstract: A testing system was built, using UV illumination at 254 nm and a cathodoluminescent phosphor screen, to measure the gain uniformity of large area (20 x 20 cm2) microchannel plates. The phosphor screen image is captured with a wide-angle CMOS digital camera (4032 x 3024 pixels) and analyzed. First a reference MCP is illuminated and the generated phosphor screen image is captured with a CCD camera. In a second step, another image is captured with the MCP under test inserted between the reference MCP and the phosphor screen. The ratio of the two images is analyzed and provides a quantitative measure of the relative gain uniformity of the MCP under test. (19 refs.)Main Heading: Image storage tubesControlled terms: CCD cameras - Light emission - Microchannels - Phosphors - PhotonsUncontrolled terms: Cathodoluminescent phosphors - Micro channel plate - Phosphor screens - Photon detector - Quantitative measures - Secondary electron emitter - Timing detectors - Visible and IR photons (vacuum) (photomultipliers, HPDs, others)Classification Code: 604 Metal Cutting and Machining - 631 Fluid Flow - 714.1 Electron Tubes - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics

Database: Compendex

Learning regularized LDA by clustering

Pang, Yanwei1; Wang, Shuang1; Yuan, Yuan2 Source: IEEE Transactions on Neural Networks and Learning Systems, v 25, n 12, p 2191-2201, December 1, 2014

; ISSN: 2162237X, E-ISSN: 21622388; DOI: 10.1109/TNNLS.2014.2306844; Article number: 6799229;

Abstract: As a supervised dimensionality reduction technique, linear discriminant analysis has a serious overfitting problem when the number of training samples per class is small. The main reason is that the between- and within-class scatter matrices computed from the limited number of training samples deviate greatly from the underlying ones. To overcome the problem without increasing the number of training samples, we propose making use of the structure of the given training data to regularize the between- and within-class scatter matrices by between- and within-cluster scatter matrices, respectively, and simultaneously. The within- and between-cluster matrices are computed from unsupervised clustered data. The within-cluster scatter matrix contributes to encoding the possible variations in intraclasses and the between-cluster scatter matrix is useful for separating extra classes. The contributions are inversely proportional to the number of training samples per class. The advantages of the proposed method become more remarkable as the number of training samples per class decreases. Experimental results on the AR and Feret face databases demonstrate the effectiveness of the proposed method. (34 refs.)Main Heading: Matrix algebraControlled terms: Discriminant analysis - Face recognition - Feature extraction - Reduction - SamplingUncontrolled terms: Clustered datum - Dimensionality reduction - Dimensionality reduction techniques - FERET face database - Linear discriminant analysis - Over fitting problem - Regularized LDA - Training sampleClassification Code: 716 Telecommunication; Radar, Radio and Television - 801 Chemistry - 802.2 Chemical Reactions - 921.1 Algebra - 922 Statistical Methods

Database: Compendex

Flowing on riemannian manifold: Domain adaptation by shifting covariance

Cui, Zhen1, 2; Li, Wen3; Xu, Dong3; Shan, Shiguang2; Chen, Xilin2; Li, Xuelong4 Source: IEEE Transactions on Cybernetics, v 44, n 12, p 2264-2273, December 1, 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2014.2305701; Article number: 6762929;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 College of Computer Science and Technology, Huaqiao University, Xiamen, China2 Key Laboratory of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences, Beijing, China3 School of Computer Engineering, Nanyang Technological University, Singapore4 Center for Optical Imagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: Domain adaptation has shown promising results in computer vision applications. In this paper, we propose a new unsupervised domain adaptation method called domain adaptation by shifting covariance (DASC) for object recognition without requiring any labeled samples from the target domain. By characterizing samples from each domain as one covariance matrix, the source and target domain are represented into two distinct points residing on a Riemannian manifold. Along the geodesic constructed from the two points, we then interpolate some intermediate points (i.e., covariance matrices), which are used to bridge the two domains. By utilizing the principal components of each covariance matrix, samples from each domain are further projected into intermediate feature spaces, which finally leads to domain-invariant features after the concatenation of these features from intermediate points. In the multiple source domain adaptation task, we also need to effectively integrate different types of features between each pair of source and target domains. We additionally propose an SVM based method to simultaneously learn the optimal target classifier as well as the optimal weights for different source domains. Extensive experiments demonstrate the effectiveness of our method for both single source and multiple source domain adaptation tasks. (36 refs.)Main Heading: Covariance matrixControlled terms: Computer vision - Object recognition - Support vector machinesUncontrolled terms: Computer vision applications - Covariance matrices - Distinct points - Domain adaptation - Invariant features - Principal Components - Riemannian manifold - SVM-based methodsClassification Code: 716 Telecommunication; Radar, Radio and Television - 723 Computer Software, Data Handling and Applications - 723.5 Computer Applications - 921 Mathematics - 922 Statistical Methods

Database: Compendex

Double-mode electrostatic dispersing prism for electron pulse time-domain compression

Wang, Chao1; Kang, Yifan2 Source: Optik, v 125, n 21, p 6352-6356, November 1, 2014

; ISSN: 00304026; DOI: 10.1016/j.ijleo.2014.05.051;

Abstract: The generalized theory of double-mode electrostatic dispersing prism for time-domain compressing electron pulse is presented. The fundamental difference between the two modes of o mode and e mode lies in the dispersive dependence of electron's time of flight on its initial kinetic energy at prism entrance: the electrons with higher initial axial energy definitely have longer time of flight for o mode, while not the case for e mode, which results from the electron pulse's U-shaped motion in the prism. The dispersive dependence of time of flight constitutes the mechanism of electron pulse compression for each mode. An example is given to demonstrate the issue of parameter choosing for the prism and to verify its tunable performance of compression. © 2014 Elsevier GmbH. (25 refs.)Main Heading: ElectronsControlled terms: Dispersions - Electrostatics - Kinetic energy - Kinetics - Prisms - Pulse compressionUncontrolled terms: Double-mode - Electron pulse - Generalized theory - Initial kinetics - Time domain - Time of flight - Tunable performance - U-shapedClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 741.3 Optical Devices and Systems - 931 Classical Physics; Quantum Theory; Relativity - 931.1 Mechanics - 951 Materials Science

Database: Compendex

Measurements of the concentration of atmospheric CO<inf>2</inf> based on OP/FTIR method and infrared reflecting scanning fourier transform spectrometry

Wei, Ru-Yi1; Zhou, Jin-Song2; Zhang, Xue-Min1, 3; Yu, Tao1, 3; Gao, Xiao-Hui1; Ren, Xiao-Qiang1 Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, v 34, n 11, p 2978-2983, November 1, 2014; Language: Chinese

; ISSN: 10000593; DOI: 10.3964/j.issn.1000-0593(2014)11-2978-06;

Publisher: Science PressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of Chinese Academy of Sciences, Key Laboratory of Spectral Imaging Technology of Chinese Academy of Sciences, Xi'an , China2 Academy of Opto-Electronics of Chinese Academy of Sciences, Key Laboratory of Computational Optical Imaging Technology of Chinese Academy of Sciences, Beijing , China3 University of Chinese Academy of Sciences, Beijing , China

Abstract: The present paper describes the observations and measurements of the infrared absorption spectra of CO<inf>2</inf> on the Earth's surface with OP/FTIR method by employing a mid-infrared reflecting scanning Fourier transform spectrometry, which are the first results produced by the first prototype in China developed by the team of authors. This reflecting scanning Fourier transform spectrometry works in the spectral range 2100~3150 cm-1 with a spectral resolution of 2 cm-1. Method to measure the atmospheric molecules was described and mathematical proof and quantitative algorithms to retrieve molecular concentration were established. The related models were performed both by a direct method based on the Beer-Lambert Law and by a simulating-fitting method based on HITRAN database and the instrument functions. Concentrations of CO<inf>2</inf> were retrieved by the two models. The results of observation and modeling analyses indicate that the concentrations have a distribution of 300~370 ppm, and show tendency that going with the variation of the environment they first decrease slowly and then increase rapidly during the observation period, and reached low points in the afternoon and during the sunset. The concentrations with measuring times retrieved by the direct method and by the simulating-fitting method agree with each other very well, with the correlation of all the data is up to 99.79%, and the relative error is no more than 2.00%. The precision for retrieving is relatively high. The results of this paper demonstrate that, in the field of detecting atmospheric compositions, OP/FTIR method performed by the Infrared reflecting scanning Fourier transform spectrometry is a feasible and effective technical approach, and either the direct method or the simulating-fitting method is capable of retrieving concentrations with high precision. (13 refs.)Main Heading: Carbon dioxideControlled terms: Absorption spectroscopy - Atmospheric composition - Fourier transform infrared spectroscopy - Fourier transforms - Light absorption - Scanning - SpectrometryUncontrolled terms: Atmospheric molecules - Beer Lambert law - Fourier transform spectrometry - Infrared spectrum - Instrument functions - Molecular concentration - Observations and measurements - Scanning mirrorClassification Code: 741 Light, Optics and Optical Devices - 801 Chemistry - 804.2 Inorganic Compounds - 921.3 Mathematical Transformations

Database: Compendex

Controlling optical bistability via interacting double dark resonances in linear quantum dot molecules

Tian, Si-Cong1; Wan, Ren-Gang2; Tong, Cun-Zhu1; Ning, Yong-Qiang1 Source: Journal of the Optical Society of America B: Optical Physics, v 31, n 11, p 2681-2688, November 1, 2014

; ISSN: 07403224; DOI: 10.1364/JOSAB.31.002681;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Chinese Academy of Sciences, Changchun, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: The behavior of optical bistability (OB) in linear triple quantum dot molecules (QDMs) using double tunneling coupling by means of a unidirectional ring cavity is investigated. The linear and nonlinear susceptibilities of the system are also investigated. The double tunneling between the quantum dots can induce the interaction of double dark resonances, which can enhance the nonlinear response of the system. The type, the hysteresis loop, and the threshold of OB can be controlled by the intensity of the double tunneling and the detuning of the probe field. Our results give insights for future experiments and applications in optics using QDMs. (57 refs.)Main Heading: Semiconductor quantum dotsControlled terms: MoleculesUncontrolled terms: Dark resonance - Non-linear response - Nonlinear susceptibilities - Probe field - Quantum dot molecules - Triple quantum - Tunneling coupling - Unidirectional ring cavityClassification Code: 714.2 Semiconductor Devices and Integrated Circuits - 931.3 Atomic and Molecular Physics

Database: Compendex

Wavelength conversion in highly nonlinear silicon - Organic hybrid slot waveguides

An, Linliang1; Liu, Hongjun1; Sun, Qibing1; Huang, Nan1; Wang, Zhaolu1 Source: Applied Optics, n 22, p 4886-4893, August 1, 2014

; ISSN: 1559-128X, E-ISSN: 2155-3165; DOI: 10.1364/AO.53.004886;

Publisher: Optical Society of American (OSA)Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xi'an, China

Abstract: Wavelength conversion based on four-wave mixing (FWM) in a silicon-organic hybrid slot waveguide is theoretically investigated in the telecommunication bands. Compared with vertical slot waveguides, the horizontal slot waveguide structure exhibits much flatter dispersion. The maximum nonlinearity coefficient γ of 1.5 × 107W-1km-1and the minimum effective mode area A<inf>eff</inf>of 0.065 μm2are obtained in a horizontal slot waveguide with a 20-nm-thick optically nonlinear layer by controlling the geometric parameters. The wavelength conversion efficiency of 7.45 dB with a pump power of 100 mW in a 4-mm-long horizontal slot waveguide is obtained. This low power on-chip wavelength convertor will have potential applications in highly integrated optical circuits. © 2014 Optical Society of America. (29 refs.)Main Heading: WaveguidesControlled terms: Crystal resonators - Four wave mixing - Low power electronics - Photonic integration technology - SiliconUncontrolled terms: Effective mode areas - Horizontal slot waveguides - Integrated optical circuit - Maximum nonlinearities - Nonlinear layers - Nonlinear silicons - Telecommunication bands - Wavelength convertorsClassification Code: 711.1 Electromagnetic Waves in Different Media - 712.1.1 Single Element Semiconducting Materials - 713 Electronic Circuits - 713.5 Electronic Circuits Other Than Amplifiers, Oscillators, Modulators, Limiters, Discriminators or Mixers - 714 Electronic Components and Tubes - 715 Electronic Equipment, General Purpose and Industrial - 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications

Database: Compendex

The research on measuring the extinction ratio of polarizing prism accurately

Hao, Chong1, 2; Wu, Yi-Ming1; Lu, Wei-Guo1; Xiao, Mao-Sen1; Li, Chun-Yan1, 2 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 12, December 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144312.1223001; Article number: 1223001;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China2 University of Chinese Academy of Sciences, Beijing , China

Abstract: In traditional method of testing the extinction rate of polarizing prism, as the incidence is not vertical and the position of extinction can't be located accurately, extinction ratio can be measured accurately neither. To solve this problem, taking Glan-Taylor prism for example, magneto-optic modulation was adopted to define the extinction place accurately, rotating the prism several times to decrease the nonlinear perturbation caused by oblique incidence. Simulation and experiment show that, the minimum and maximum light intensity can be gained, the extinction rate was also obtained and fulfilled the precision requirement. (12 refs.)Main Heading: PrismsControlled terms: Light extinction - Light polarization - ModulationUncontrolled terms: Extinction rates - Extinction ratios - Indirect modulation - Light intensity - Nonlinear perturbations - Oblique incidence - Optic modulation - Polarizing prismsClassification Code: 716 Telecommunication; Radar, Radio and Television - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741.1 Light/Optics - 741.3 Optical Devices and Systems

Database: Compendex

Measuring the fractional topological charge of LG beams by using interference intensity analysis

Li, Xinzhong1, 2; Tai, Yuping3; Lv, Fangjie1; Nie, Zhaogang4 Source: Optics Communications, v 334, p 235-239, January 15, 2015

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.08.020;

Database: Compendex

Stabilizing the optical parametric oscillator cavity by fringe-locking technique in preparation of squeezed state of light

Qu, Wen-Yan1, 2; Song, Jia-Zheng1; Feng, Fei1; Xue, Yu-Lang1; Zhang, Tong-Yi1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 9, September 1, 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144309.0914004; Article number: 0914004;

Abstract: A fringe-locking technique was employed to stabilize the optical parametric oscillator cavity, which would be affected by external environmental disturbance, such as vibration and airflow. First, how the locking point influence the squeezing degree was analyzed theoretically, the results show that position at half of the transmission peak could be the best locking point. Then the fringe-locking technique was applied to achieve the resonance between the optical parametric oscillator cavity and the injected infrared light experimentally. The experimental results show that the length variance of the cavity in continuous operation over 2 h is 7.27 nm and the longest locking time is 3.8 h, which is sufficient for the detection of the squeezed states of light. (16 refs.)Main Heading: Locks (fasteners)Controlled terms: Optical parametric oscillators - Quantum opticsUncontrolled terms: Continuous operation - Environmental disturbances - Error signal - Fringe-locking - Infrared light - Locking technique - Squeezed state - Transmission peaksClassification Code: 601.3 Mechanisms - 741.1 Light/Optics - 744.9 Laser Applications

Database: Compendex

Optical Bloch oscillations of an Airy beam in a photonic lattice with a linear transverse index gradient

Xiao, Fajun1; Li, Baoran1; Wang, Meirong1; Zhu, Weiren2; Zhang, Peng1, 3; Liu, Sheng1; Premaratne, Malin2; Zhao, Jianlin1 Source: Optics Express, v 22, n 19, p 22763-22770, September 22, 2014; E-ISSN: 10944087; DOI: 10.1364/OE.22.022763;

Publisher: Optical Society of American (OSA)Author affiliation: 1 Key Laboratory of Space Applied Physics and Chemistry, School of Science, Northwestern Polytechnical University, Xi'an, China2 Advanced Computing and Simulation Laboratory (A L), Department of Electrical and Computer Systems Engineering, Monash University, Clayton; VIC, Australia3 State Key Laboratory of Transient Optics and Photonics, Chinese Academy of Sciences, Xi'an, China

Abstract: We theoretically report the existence of optical Bloch oscillations (BO) of an Airy beam in a one-dimensional optically induced photonic lattice with a linear transverse index gradient. The Airy beam experiencing optical BO shows a more robust non-diffracting feature than its counterparts in free space or in a uniform photonic lattice. Interestingly, a periodical recurrence of Airy shape accompanied with constant alternation of its acceleration direction is also found during the BO. Furthermore, we demonstrate that the period and amplitude of BO of an Airy beam can be readily controlled over a wide range by varying the index gradient and/or the lattice period. Exploiting these features, we propose a scheme to rout an Airy beam to a predefined output channel without losing its characteristics by longitudinally modulating the transverse index gradient. © 2014 Optical Society of America. (41 refs.)Main Heading: Optical latticesControlled terms: PhotonicsUncontrolled terms: Bloch oscillations - Free spaces - Lattice periods - Nondiffracting - Optically-induced photonic lattices - Output channels - Photonic lattice - Transverse index gradientClassification Code: 712 Electronic and Thermionic Materials - 717 Optical Communication - 744 Lasers - 744.8 Laser Beam Interactions

Database: Compendex

Multi-bit quantum random number generation by measuring positions of arrival photons

Yan, Qiurong1, 2; Zhao, Baosheng2; Liao, Qinghong1; Zhou, Nanrun1 Source: Review of Scientific Instruments, v 85, n 10, October 1, 2014

; ISSN: 00346748, E-ISSN: 10897623; DOI: 10.1063/1.4897485; Article number: 103116;

Publisher: American Institute of Physics Inc.Author affiliation: 1 Department of Electronics Information Engineering, Nanchang University, Nanchang, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: We report upon the realization of a novel multi-bit optical quantum random number generator by continuously measuring the arrival positions of photon emitted from a LED using MCP-based WSA photon counting imaging detector. A spatial encoding method is proposed to extract multi-bits random number from the position coordinates of each detected photon. The randomness of bits sequence relies on the intrinsic randomness of the quantum physical processes of photonic emission and subsequent photoelectric conversion. A prototype has been built and the random bit generation rate could reach 8 Mbit/s, with random bit generation efficiency of 16 bits per detected photon. FPGA implementation of Huffman coding is proposed to reduce the bias of raw extracted random bits. The random numbers passed all tests for physical random number generator. © 2014 AIP Publishing LLC. (23 refs.)Main Heading: Random number generationControlled terms: Number theory - Photoelectricity - Photons - Random processesUncontrolled terms: FPGA implementations - Intrinsic randomness - Photoelectric conversion - Photon-counting imaging - Physical random number generators - Position coordinates - Quantum random number generators - Random bit generationsClassification Code: 741.1 Light/Optics - 921 Mathematics - 922.1 Probability Theory - 922.2 Mathematical Statistics

Database: Compendex

Heterostructured cathode with graded bandgap window-layer for photon-enhanced thermionic emission solar energy converters

Yang, Yang1; Yang, Wenzheng1; Sun, Chuandong1 Source: Solar Energy Materials and Solar Cells, v 132, p 410-417, 2014

; ISSN: 09270248; DOI: 10.1016/j.solmat.2014.09.027;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, China

Abstract: A heterostructured cathode having a graded bandgap window-layer is proposed in this study to improve the performance of photon-enhanced thermionic emission (PETE) solar energy converters. A model based on a one-dimensional steady-state equation is developed to analyze the characteristics of the proposed device. This model is used to calculate the conversion efficiency of a PETE device with an AlxGa1-xAs/GaAs cathode. The built-in electric field induced by the bandgap gradation in the window-layer is shown to improve the efficiency because of the reduction of contact surface recombination losses and efficient collection of photogenerated electrons. This field is unaffected by temperature variation, and the improvement of efficiency is sustained at elevated temperatures. The effect of window-layer parameters and cathode thickness on efficiency is discussed. We also show that the efficiency maximizes at lower temperatures for cathodes with lower electron affinities. Moreover an optimal value exists for anode work function at a given anode temperature, thus providing guidance for the optimum design of barrier conditions for both cathode and anode. © 2014 Elsevier B.V. All rights reserved. (33 refs.)Main Heading: CathodesControlled terms: Electric fields - Electric losses - Energy gap - Equations of state - Heterojunction bipolar transistors - Photons - Solar energy - Thermionic emissionUncontrolled terms: Built-in electric fields - Cathode and anode - Cathode thickness - Elevated temperature - Lower temperatures - One dimensional steady state - Photogenerated electrons - Temperature variationClassification Code: 615.2 Solar Power - 701.1 Electricity: Basic Concepts and Phenomena - 714.1 Electron Tubes - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics - 921 Mathematics - 931.3 Atomic and Molecular Physics

Database: Compendex

Research on measurement and correction of a fish-eye image distortion

Wang, Zefeng1; Lei, Yangjie1; Zhang, Zhi1; Zhang, Zhaohui1; Zhang, Hui1; Huang, Jijiang1; Yi, Bo1; Liao, Jiawen1 Source: Proceedings of SPIE - The International Society for Optical Engineering, v 9282, 2014

; ISSN: 0277786X, E-ISSN: 1996756X; ISBN-13: 9781628413571; DOI: 10.1117/12.2068149; Article number: 928214; Conference: 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, AOMATT 2014, April 26, 2014 - April 29, 2014; Sponsor: Chinese Academy of Sciences, Institute of Optics and Electronics (IOE); Chinese Optical Society (COS);

Publisher: SPIEAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi Province, China

Abstract: Fisheye lenses have the advantages of short focal length and large field of view. However, by using the "non-similar" imaging principle, they artificially introduce a large barrel distortion. In order to improve the quality of the images correction of distortion is required. This article analyzes the polar distortion correction model, raised a simple distortion coefficient calibration method and the use of bilinear interpolation method for gray level interpolation. Compared to other methods, this method is easier to reinforce and achieves high accuracy, and it can be easily implemented in the hardware system. At the end of the paper we introduced a device correction for a fisheye CCD camera. Based on the original data, a distortion correction model is established. In order to minimize the error, the correction was divided into three sections, and the image is well recovered. © 2014 SPIE. (5 refs.)Main Heading: CCD camerasControlled terms: Distortion (waves) - Image reconstruction - Interpolation - Manufacture - Optical data processing - Optical testingUncontrolled terms: Bilinear interpolation method - Correction of distortion - Distortion coefficients - Distortion correction - Fisheye images - Image correction - Large field of views - Optical measurementClassification Code: 537.1 Heat Treatment Processes - 711.1 Electromagnetic Waves in Different Media - 714.2 Semiconductor Devices and Integrated Circuits - 741 Light, Optics and Optical Devices - 741.3 Optical Devices and Systems - 921.6 Numerical Methods

Database: Compendex

Effect of energy density and feeding speed on micro-hole drilling in C/SiC composites by picosecond laser

Liu, Yongsheng1; Wang, Chunhui1; Li, Weinan2; Zhang, Litong1; Yang, Xiaojun2; Cheng, Guanghua2; Zhang, Qing1 Source: Journal of Materials Processing Technology, v 214, n 12, p 3131-3140, December 2014

; ISSN: 09240136; DOI: 10.1016/j.jmatprotec.2014.07.016Author affiliation: 1 Science and Technology on Thermostructure Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 10068, Shaanxi, China

Abstract: The effect of energy density and feeding speed on micro-holes was investigated, which were machined in C/SiC composites by picosecond laser. Morphologies and elemental compositions of the machined holes in 2 mm and 3 mm thickness specimens were analyzed. The results indicated that both energy density and feeding speed had remarkable effect on the quality of micro-holes, especially on the exit side and cross-section of micro-holes. While the circularity of drilling holes on the entry side was affected by the energy density and feeding speed slightly. Additionally, the machining debris also played an important role in the quality of micro-holes. The micro-holes were consisted with three elements C, Si, and O, and those predominantly attributed to CC (sp2), CC (sp3) and SiO bonds. Moreover, the laser machining process was discussed, which was responsible for the formation of the debris. © 2014 Elsevier B.V. (23 refs.)Main Heading: FeedingControlled terms: Debris - Scanning electron microscopy - X ray photoelectron spectroscopyUncontrolled terms: C/SiC composites - Drilling holes - Elemental compositions - Energy density - Feeding speed - Laser machining - Laser process - Picosecond laserClassification Code: 452.3 Industrial Wastes - 691.2 Materials Handling Methods - 741.1 Light/Optics - 801 Chemistry

Database: Compendex

Erratum: The performance of new polymer solar cells based on thiophene and thienyl-quinoxaline with the post treatments (Materials Letters (2014) 122 (74-77))

Gao, Bowen1, 3; Gao, Chao2; Wu, Haimei2; Que, Wenxiu3; Wei, Wei1 Source: Materials Letters, v 129, p 213, August 15, 2014

; ISSN: 0167577X; DOI: 10.1016/j.matlet.2014.05.053;

Publisher: ElsevierAuthor affiliation: 1 State Key Laboratory of Transient Opticsand Photonics, Xian Institute of Optics and Precision Mechanics, Chinese Academy of Science (CAS), Xian, Shaanxi 710119, China2 Xian Modern Chemistry Research Institute, Xian, Shaanxi 710065, China3 School of Electronics and Information Engineering, Xian Jiaotong University, Xian, Shaanxi 710049, China

Database: Compendex

Bright and dark square pulses generated from a graphene-oxide mode-locked ytterbium-doped fiber laser

Lin, Rong-Yong1; Wang, Yong-Gang2; Yan, Pei-Guang1; Zhang, Ge-Lin1; Zhao, Jun-Qing1; Li, Hui-Quan1; Huang, Shi-Sheng1; Cao, Guang-Zhong3; Duan, Ji-An4 Source: IEEE Photonics Journal, v 6, n 3, June 2014

; ISSN: 19430655; DOI: 10.1109/JPHOT.2014.2319099; Article number: 6807644;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, Shenzhen University, College of Electronic Science and Technology, Shenzhen 518060, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Shenzhen Key Laboratory of Electromagnetic Control, Shenzhen University, Shenzhen 518060, China4 State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083, China

Abstract: The observation of the bright pulses and dark square pulses in a graphene-oxide saturable absorber (GOSA) passively mode-locked ytterbium-doped fiber laser has been investigated experimentally. Bright pulses are achieved at a pump power of &sim;200 mW. However, the dark-square-pulse generation starts at a much higher pump power of &sim;450 mW. At the maximum pump power of 600 mW, the dark-square-pulse bunches and harmonic mode locking (HML) can be also obtained by tuning the polarization controller (PC) to different orientations. It is the first demonstration of the bunches and HML of dark square pulses in a GOSA passively mode-locked ytterbium-doped fiber laser with large normal dispersion cavity. © 2014 IEEE. (35 refs.)Main Heading: Optical pumpingControlled terms: Fiber lasers - Graphene - Locks (fasteners) - Mode-locked fiber lasers - Passive mode locking - Pulse generators - Pumps - Saturable absorbers - YtterbiumUncontrolled terms: Graphene-oxide - Harmonic mode locking - Maximum pump power - Normal dispersion - Passively mode-locked - Polarization controllers - Square pulse - Ytterbium-doped fiber lasersClassification Code: 547.2 Rare Earth Metals - 601.3 Mechanisms - 618.2 Pumps - 713.4 Pulse Circuits - 741.1 Light/Optics - 741.1.2 Fiber Optics - 744.1 Lasers, General - 744.4 Solid State Lasers - 761 Nanotechnology - 804 Chemical Products Generally

Database: Compendex

Image esthetic assessment using both hand-crafting and semantic features

Guo, Lihua1; Xiong, Yangchao1; Huang, Qinghua1; Li, Xuelong2 Source: Neurocomputing, v 143, p 14-26, November 2, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2014.06.029;

Publisher: ElsevierAuthor affiliation: 1 School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510640, China2 Center for OPTical IMagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi'an 710119, China

Abstract: Automatically assessing the visual esthetics of images is of great interest in high-level vision research and has drawn much attention in recent years. Traditional methods heavily depend on the performance of subject region extraction. This paper proposes to use semantic features in the esthetic assessment system because they can implicitly represent the image topic and be helpful if the subject region extraction fails. Accordingly, a framework combining the hand-crafting features with semantic features is proposed to evaluate image esthetic quality. The experimental results show that the semantic features can improve the performance of image esthetic assessment. © 2014 Elsevier B.V. (29 refs.)Main Heading: Image processingControlled terms: Data mining - Extraction - SemanticsUncontrolled terms: Assessment system - Features extraction - High-level visions - Image esthetic assessment - Region detection - Region extraction - Semantic featuresClassification Code: 723.3 Database Systems - 741 Light, Optics and Optical Devices - 802.3 Chemical Operations - 903.2 Information Dissemination

Database: Compendex

Analysis of Lorentzian line shape function broadened by non-sinusoidal wavelength modulation

Sun, You-Qun1; Wang, Yun-Tao1; Ruan, Chi1; Xu, Song-Song1 Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, v 34, n 3, p 597-600, March 2014; Language: Chinese

; ISSN: 10000593; DOI: 10.3964/j.issn.1000-0593(2014)03-0597-04;

Abstract: In the present work, the Fourier analysis of Lorentzian line shape broadened by non-sinusoidal wavelength modulation was investigated, in which the third order and above harmonic items were ignored. The analytical expression of n-order Fourier coefficient was brought out, where a variable K named harmonic distortion to characterize the ratio of the second harmonic to the first harmonic was introduced. Numerical simulations based on the cases of K>0.01 and K<0.01 were carried out, and the result shows: non-sinusoidal modulation has little effect compared with the sinusoidal modulation when K value is less than 0.01, however, if K value is about 0.1 or higher, the center of the Fourier amplitude curve would deviate from the origin of coordinates. With the increase in the harmonic distortion, the deviation of the curve grows, and high order harmonics are more sensitive to the non-sinusoidal modulation compared with the low order harmonics. In addition, when harmonic distortion cannot be ignored, for example K>0.01, the effect of different depths of modulation on the odd and even order harmonic amplitude curve is significant. And the numerical simulation shows there exists an optimum value of modulation depth which could minimize the impact of the harmonic distortion, and both large K value and small K value would cause a great error. The conclusion of this work could be applied in error analysis of wavelength modulation spectroscopy system. And the results are helpful to deepening understanding of WMS and would be the important reference for some kind of frequency stabilization technology in laser instrument. (11 refs.)Main Heading: ModulationControlled terms: Computer simulation - Fourier analysis - Harmonic analysis - Harmonic distortion - Molecular spectroscopy - Numerical models - WavelengthUncontrolled terms: Analytical expressions - Frequency stabilization - High order harmonics - Lorentzian line shape - Second harmonics - Sinusoidal modulation - Wavelength modulation - Wavelength modulation spectroscopyClassification Code: 711 Electromagnetic Waves - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 723.5 Computer Applications - 741.3 Optical Devices and Systems - 921 Mathematics - 921.6 Numerical Methods

Database: Compendex

Weakly supervised multi-graph learning for robust image reranking

Deng, Cheng1; Ji, Rongrong2; Tao, Dacheng3; Gao, Xinbo1; Li, Xuelong4 Source: IEEE Transactions on Multimedia, v 16, n 3, p 785-795, April 2014

; ISSN: 15209210; DOI: 10.1109/TMM.2014.2298841; Article number: 6705682;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Electronic Engineering, Xidian University, Xi'an 710071, Shaanxi, China2 Department of Cognitive Science, School of Information Science and Technology, Xiamen University, Xiamen 31005, Fujian, China3 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology, Broadway NSW 2007, Australia4 Center for OPTical IMagery Analysis and Learning (OPTIMAL), Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, Shaanxi, China

Abstract: Visual reranking has been widely deployed to refine the traditional text-based image retrieval. Its current trend is to combine the retrieval results from various visual features to boost reranking precision and scalability. And its prominent challenge is how to effectively exploit the complementary property of different features. Another significant issue raises from the noisy instances, from manual or automatic labels, which makes the exploration of such complementary property difficult. This paper proposes a novel image reranking by introducing a new Co-Regularized Multi-Graph Learning (Co-RMGL) framework, in which intra-graph and inter-graph constraints are integrated to simultaneously encode the similarity in a single graph and the consistency across multiple graphs. To deal with the noisy instances, weakly supervised learning via co-occurred visual attribute is utilized to select a set of graph anchors to guide multiple graphs alignment and fusion, and to filter out those pseudo labeling instances to highlight the strength of individual features. After that, a learned edge weighting matrix from a fused graph is used to reorder the retrieval results. We evaluate our approach on four popular image retrieval datasets and demonstrate a significant improvement over state-of-the-art methods. © 2014 IEEE. (49 refs.)Main Heading: Data processingControlled terms: Image retrieval - Supervised learningUncontrolled terms: Attributes - co-occurred patterns - multiple graphs - Re-ranking - Weakly supervised learningClassification Code: 723 Computer Software, Data Handling and Applications

Database: Compendex

Night vision image fusion based on phase information modulation and image enhancement technique

Zhou, Jiang1, 2; Zhai, Bo1; Han, Ya Meng1; Qu, You Shan1; Yu, Ya Li1, 2 Source: Applied Mechanics and Materials, v 568-570, p 663-667, 2014, Measurement Technology and its Application III

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038351382; DOI: 10.4028/www.scientific.net/AMM.568-570.663;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China

Abstract: In order to observe night vision image easily, a new image fusion method is designed to improve the detail information of night vision images in a simple and efficient way. Instead of the traditional Multi-resolution analysis and spatial transform approach, the designed method highlights the detail information of night vision images by phase modulation and image enhancement technique. In the designed approach, the phase spectrum and amplitude spectrum of the visible and infrared images are extracted using FFT firstly, and then the phase spectra of two images are exchanged and the IFFT is applied to the processed images to produce phase information images. To compensate for the blurring caused by phase modulation, the high-frequency information of the processed infrared image is segmented and applied to the reconstruction of the color night vision image. Finally, color night vision image is fused by assigning the two-modulated images to red and green channels respectively, and the segmented image to blue channel. The experimental results show that the details of the fused image by the new method are richer than those of the images fused by the traditional methods, and the designed algorithm with a little amount of calculation can be easily realized in real-time processing systems. © (2014) Trans Tech Publications, Switzerland. (10 refs.)Main Heading: VisionControlled terms: Color - Image enhancement - Image fusion - Image segmentation - Infrared imaging - Phase modulationUncontrolled terms: Amplitude spectra - Color night vision - High-frequency informations - Image fusion methods - Night vision images - Phase information - Realtime processing - Spatial transformClassification Code: 716 Telecommunication; Radar, Radio and Television - 723.2 Data Processing and Image Processing - 741.1 Light/Optics - 741.2 Vision - 746 Imaging Techniques

Database: Compendex

Action recognition by spatio-temporal oriented energies

Zhen, Xiantong1, 2; Shao, Ling1, 2; Li, Xuelong3 Source: Information Sciences, v 281, p 295-309, October 10, 2014

; ISSN: 00200255; DOI: 10.1016/j.ins.2014.05.021;

Publisher: Elsevier Inc.Author affiliation: 1 College of Electronic and Information Engineering, Nanjing University of Information Science and Technology, Nanjing, Jiangsu 210044, China2 Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield S1 3JD, United Kingdom3 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, Shaanxi 710119, China

Abstract: In this paper, we present a unified representation based on the spatio-temporal steerable pyramid (STSP) for the holistic representation of human actions. A video sequence is viewed as a spatio-temporal volume preserving all the appearance and motion information of an action in it. By decomposing the spatio-temporal volumes into band-passed sub-volumes, the spatio-temporal Laplacian pyramid provides an effective technique for multi-scale analysis of video sequences, and spatio-temporal patterns with different scales could be well localized and captured. To efficiently explore the underlying local spatio-temporal orientation structures at multiple scales, a bank of three-dimensional separable steerable filters are conducted on each of the sub-volume from the Laplacian pyramid. The outputs of the quadrature pair of steerable filters are squared and summed to yield a more robust oriented energy representation. To be further invariant and compact, a spatio-temporal max pooling operation is performed between responses of the filtering at adjacent scales and over spatio-temporal neighbourhoods. In order to capture the appearance, local geometric structure and motion of an action, we apply the STSP on the intensity, 3D gradients and optical flow of video sequences, yielding a unified holistic representation of human actions. Taking advantage of multi-scale, multi-orientation analysis and feature pooling, STSP produces a compact but informative and invariant representation of human actions. We conduct extensive experiments on the KTH, UCF Sports and HMDB51 datasets, which shows the unified STSP achieves comparable results with the state-of-the-art methods. © 2014 Elsevier Inc. All rights reserved. (55 refs.)Main Heading: Image recognitionControlled terms: Decomposition - Laplace transforms - Motion estimation - Video recordingUncontrolled terms: Action recognition - Invariant representation - Laplacian Pyramid - Local geometric structures - Spatio-temporal - Spatiotemporal patterns - State-of-the-art methods - Steerable filtersClassification Code: 716 Telecommunication; Radar, Radio and Television - 802.2 Chemical Reactions - 921.3 Mathematical Transformations

Database: Compendex

Tunable wavefront coded imaging system based on detachable phase mask: Mathematical analysis, optimization and underlying applications

Zhao, Hui1; Wei, Jingxuan2 Source: Optics Communications, v 326, p 35-42, September 1, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2014.04.023;

Publisher: ElsevierAuthor affiliation: 1 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Science, No. 17, Xinxi Road, High-tech zone, Xi'an 710119, China2 School of Computer Science and Technology, Xidian University, No. 2, South Taibai Road, Xi'an 710071, China

Abstract: The key to the concept of tunable wavefront coding lies in detachable phase masks. Ojeda-Castaneda et al. (Progress in Electronics Research Symposium Proceedings, Cambridge, USA, July 5-8, 2010) described a typical design in which two components with cosinusoidal phase variation operate together to make defocus sensitivity tunable. The present study proposes an improved design and makes three contributions: (1) A mathematical derivation based on the stationary phase method explains why the detachable phase mask of Ojeda-Castaneda et al. tunes the defocus sensitivity. (2) The mathematical derivations show that the effective bandwidth wavefront coded imaging system is also tunable by making each component of the detachable phase mask move asymmetrically. An improved Fisher information-based optimization procedure was also designed to ascertain the optimal mask parameters corresponding to specific bandwidth. (3) Possible applications of the tunable bandwidth are demonstrated by simulated imaging. © 2014 Elsevier B.V. (17 refs.)Main Heading: Optical designControlled terms: Bandwidth - Fisher information matrix - Imaging systems - Optimization - Sensitivity analysis - WavefrontsUncontrolled terms: Electronics research - Mathematical analysis - Mathematical derivation - Optimization procedures - Phase masks - Stationary phase methods - Tunable bandwidth - Wave-front codingClassification Code: 716.1 Information Theory and Signal Processing - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 746 Imaging Techniques - 921 Mathematics - 921.5 Optimization Techniques - 922 Statistical Methods

Database: Compendex

Research of spectrum signal-to-noise ratio of large aperture static imaging spectrometer

Wang, Shuang1, 2; Xiangli, Bin3; Li, Li-Bo1, 2; Pi, Hai-Feng1, 2 Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis, v 34, n 3, p 851-856, March 2014; Language: Chinese

; ISSN: 10000593; DOI: 10.3964/j.issn.1000-0593(2014)03-0851-06;

Publisher: Science PressAuthor affiliation: 1 Key Laboratory of Spectral Imaging Technique, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China3 Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100093, China

Abstract: The process of acquiring hyperspectral data cube of a Large Aperture Static Imaging Spectrometer (LASIS) includes several vital and essential steps, such as interferometer modulation, rectangular convolution sampling by pixels of detector and spectra retrieving. In this process, how to precisely evaluate the Signal-Noise Ratio (SNR) of spectra and how to wholly establish a related evaluation model were both generally very complicated. After a full consideration of the transmission process, utilizing the theory of rectangular convolution sampling and the spectral retrieving method regarding the computation of real part of the discrete Fourier transform of interferogram, formulas of both spectral signal and spectral noise were deduced theoretically, and then a evaluation model regarding the spectral SNR of LASIS was established. By using this model and other design factors of LASIS involving the wavenumber related optical transmittance, the interferometer beam splitter efficiency, the detector quantum efficiency and the main circuit noise, a simulation of spectral SNR was implemented. The simulation result was compared with the measurement result of the SNR of a LASIS instrument. The SNR lines and trends of the two match each other basically in single spectral band. The average deviation between them is proved to be 3.58%. This comparison result demonstrates the feasibility and effectiveness of the evaluation model. This SNR evaluation model consisting of the main technical aspects of typical LASIS instrument from the input spectral radiation to the output spectrum data is possible to be applied widely in practical design and implement of LASIS, as well as may provide valuable reference on SNR calculation and evaluation for other imaging spectrometers. (15 refs.)Main Heading: Signal to noise ratioControlled terms: Computer simulation - Convolution - Discrete Fourier transforms - Interferometers - SpectrometersUncontrolled terms: Design and implements - Detector quantum efficiencies - Evaluation modeling - Fourier-transform imaging - Hyperspectral Data - Imaging spectrometers - Noise - Radiation transmissionClassification Code: 716.1 Information Theory and Signal Processing - 723.5 Computer Applications - 921.3 Mathematical Transformations - 941.3 Optical Instruments

Database: Compendex

Aperiodic signals processing via parameter-tuning stochastic resonance in a photorefractive ring cavity

Li, Xuefeng1; Cao, Guangzhan2; Liu, Hongjun2 Source: AIP Advances, v 4, n 4, April 2014; E-ISSN: 21583226; DOI: 10.1063/1.4871406; Article number: 047111;

Publisher: American Institute of Physics Inc.Author affiliation: 1 School of Science, Xi'An University of Post and Telecommunications, Xi'an, 710121, China2 Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an, 710119, China

Abstract: Based on solving numerically the generalized nonlinear Langevin equation describing the nonlinear dynamics of stochastic resonance by Fourth-order Runge-Kutta method, an aperiodic stochastic resonance based on an optical bistable system is numerically investigated. The numerical results show that a parameter-tuning stochastic resonance system can be realized by choosing the appropriate optical bistable parameters, which performs well in reconstructing aperiodic signals from a very high level of noise background. The influences of optical bistable parameters on the stochastic resonance effect are numerically analyzed via cross-correlation, and a maximum cross-correlation gain of 8 is obtained by optimizing optical bistable parameters. This provides a prospective method for reconstructing noise-hidden weak signals in all-optical signal processing systems. © 2014 Author(s). (30 refs.)Main Heading: TuningControlled terms: Circuit resonance - Differential equations - Magnetic resonance - Optical correlation - Runge Kutta methods - Signal processingUncontrolled terms: All-optical signal processing - Cross correlations - Fourth-order Runge-Kutta methods - Langevin equation - Numerical results - Parameter-tuning - Photo-refractive - Stochastic resonancesClassification Code: 701.2 Magnetism: Basic Concepts and Phenomena - 703.1.1 Electric Network Analysis - 713 Electronic Circuits - 716.1 Information Theory and Signal Processing - 741.1 Light/Optics - 921.2 Calculus - 921.6 Numerical Methods

Database: Compendex

Transition from Eu3+ to Eu2+ in SiO<inf>2</inf> matrix prepared by sol-gel

Zhang, Dekai1, 2; Hu, Xiaoyun1, 2; Jing, Guangyin1, 2; Liu, Enzhou4; Fan, Jun4; Zhang, Guodong1; Hou, Xun1, 3 Source: Journal of Nanoscience and Nanotechnology, v 14, n 5, p 3642-3647, May 2014

; ISSN: 15334880, E-ISSN: 15334899; DOI: 10.1166/jnn.2014.8023;

Publisher: American Scientific PublishersAuthor affiliation: 1 Department of Physics, Northwest University, Xi'an 710069, China2 National Photoelectric Technology and Functional Materials, Application of Science and Technology International Cooperation Base, Northwest University, Xi'an 710069, China3 State Key Laboratory of Transient Optics and Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710068, China4 School of Chemical Engineering, Northwest University, Xi'an 710069, China

Abstract: Activated silica matrix fluorescent materials doped with Al3+ and Eu2+ are prepared by sol-gel method. The effects of different atmospheres and annealing temperatures on luminescent properties are characterized by analysis techniques including X-ray diffraction, infrared spectroscopy and fluorescence spectra. When being excited at 281 nm wavelength, the fluorescent materials show a strong broad blue emission band, with the emission center at 430 nm and the FWHM of 56 nm. The results indicate that the blue emission is derived from 4f<inf>6</inf> 5d to 4f<inf>7</inf> transition of the Eu2+ ions. Al3+ ion plays a key role in the process of deoxidization from Eu3+ to Eu2+. Al3+ and B3+ can enhance the blue-emission intensity. Also it is found that the highest luminescent intensity of the samples occurs in the sample Eu-03 annealed at 1150 °C in N<inf>2</inf> atmosphere. Copyright © 2014 American Scientific Publishers. (20 refs.)Main Heading: AluminumControlled terms: Fluorescence - Infrared spectroscopy - Sol-gel process - Sol-gels - X ray diffractionUncontrolled terms: Analysis techniques - Annealing temperatures - Blue emission bands - Emission centers - Fluorescence spectra - Fluorescent materials - Luminescent intensity - Luminescent propertyClassification Code: 541.1 Aluminum - 741.1 Light/Optics - 804 Chemical Products Generally - 813.1 Coating Techniques - 931.3 Atomic and Molecular Physics

Database: Compendex

Spectral embedded hashing for scalable image retrieval

Chen, Lin1; Xu, Dong1; Tsang, Ivor Wai-Hung1; Li, Xuelong2 Source: IEEE Transactions on Cybernetics, v 44, n 7, p 1180-1190, July 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2281366; Article number: 6670060;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 School of Computer Engineering, Nanyang Technological University, Singapore 639798, Singapore2 Center for Optical Imagery Analysis and Learning (OPTIMAL), State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: We propose a new graph based hashing method called spectral embedded hashing (SEH) for large-scale image retrieval. We first introduce a new regularizer into the objective function of the recent work spectral hashing to control the mismatch between the resultant hamming embedding and the low-dimensional data representation, which is obtained by using a linear regression function. This linear regression function can be employed to effectively handle the out-of-sample data, and the introduction of the new regularizer makes SEH better cope with the data sampled from a nonlinear manifold. Considering that SEH cannot efficiently cope with the high dimensional data, we further extend SEH to kernel SEH (KSEH) to improve the efficiency and effectiveness, in which a nonlinear regression function can also be employed to obtain the low dimensional data representation. We also develop a new method to efficiently solve the approximate solution for the eigenvalue decomposition problem in SEH and KSEH. Moreover, we show that some existing hashing methods are special cases of our KSEH. Our comprehensive experiments on CIFAR, Tiny-580K, NUS-WIDE, and Caltech-256 datasets clearly demonstrate the effectiveness of our methods. © 2013 IEEE. (33 refs.)Main Heading: Image retrievalControlled terms: Clustering algorithms - Eigenvalues and eigenfunctionsUncontrolled terms: Approximate solution - Data representations - Eigenvalue decomposition - hashing - High dimensional data - Non-linear regression - scalable - Spectral embeddedClassification Code: 721 Computer Circuits and Logic Elements - 741 Light, Optics and Optical Devices - 921.1 Algebra

Database: Compendex

Line-plane-switching infrared fiber imaging bundle

Zhan, Huan1, 2; Yan, Xingtao1, 2; Zhang, Aidong1; Li, Fu1; Yang, Jianfeng1; Lin, Aoxiang1 Source: Optics InfoBase Conference Papers, 2014, CLEO: QELS_Fundamental Science, CLEO_QELS 2014; E-ISSN: 21622701; ISBN-13: 9781557529992; Conference: CLEO: QELS_Fundamental Science, CLEO_QELS 2014, June 8, 2014 - June 13, 2014;

Abstract: Using line-plane-switching infrared fiber imaging bundle made from As2S3 glass fibers with core of 40 μm, clad of 45 μm, and error of 1% in diameter, we demonstrated push-broom infrared sensing imaging. © 2014 OSA. (5 refs.)Uncontrolled terms: Imaging bundles - Infrared fibers - Infrared sensing

Database: Compendex

A Low-light-level CCD camera design and implementation of low cost and large field

Yan, Su1; Li, Hua1; Wang, Hao1, 2; Zhou, Zuofeng1; Yan, Aqi1, 2 Source: WIT Transactions on Engineering Sciences, 84 VOLUME 1, p 271-276, 2014, Manufacture Engineering and Environment Engineering

; ISSN: 17433533; ISBN-13: 9781845648244; DOI: 10.2495/MEEE20130381; Conference: 2013 International Conference on Manufacture Engineering and Environment Engineering, MEEE 2013, June 27, 2013 - June 28, 2013; Sponsor: WIT Transactions on Engineering Sciences;

Publisher: WITPressAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences, Xi'an, China2 Graduate University of Chinese Academy of Science, Beijing, China

Abstract: A low-light-level CCD camera is a high-tech, involving optics, electronics, machinery, and computer science in many fields. The technology now plays a crucial role in detection of early warning, identification tracking, public security, fire alarm and applications in many other fields. But the high cost make many consumers give it up.This paper mainly expands a low-light-level CCD camera design which is low cost and large field. And this paper introduces the camera structure in electronics. Experiment results in paper are posted. © 2014 WIT Press. (4 refs.)Main Heading: LightControlled terms: CCD cameras - Machinery - ManufactureUncontrolled terms: AD converters - Camera design - Camera structures - Early warning - FPGA implementations - Large field - Low-light-level - Public securityClassification Code: 537.1 Heat Treatment Processes - 601 Mechanical Design - 714.2 Semiconductor Devices and Integrated Circuits - 741.1 Light/Optics

Database: Compendex

Instantaneous three-dimensional imaging using supercontinuum and ultrafast optical Kerr gate of tellurite glass

Tan, Wenjiang1; Zhou, Zhiguang2; Lin, Aoxiang2; Tong, Junyi3; Si, Jinhai1; Hou, Xun1 Source: Optical Engineering, v 53, n 4, April 2014

; ISSN: 00913286, E-ISSN: 15602303; DOI: 10.1117/1.OE.53.4.043108; Article number: 043108;

Publisher: SPIEAuthor affiliation: 1 Xi'An Jiaotong University, School of Electronic and Information Engineering, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, Xianning-xilu 28, Xi'an 710049, China2 Chinese Academy of Sciences, Xi'An Institute of Optics and Precision Mechanics, State Key Laboratory of Transient Optics and Photonics, Xi'an 710119, China3 Xi'An University of Technology, Departments of Applied Physics, Xi'an 710048, China

Abstract: An instantaneous three-dimensional imaging technique using a chirped supercontinuum and an ultrafast optical Kerr gate, in which a sapphire plate and a TeO<inf>2</inf>-ZnO-Na<inf>2</inf>O oxide glass were used to generate the chirped supercontinuum and the ultrafast optical Kerr gate, respectively, is demonstrated. This technique is applicable to ultrafast shape measurement, such as shape imaging of moving objects, or imaging of laserinduced refractive index changes in transparent media. © 2014 Society of Photo-Optical Instrumentation Engineers. (19 refs.)Main Heading: GlassControlled terms: Imaging systems - Sapphire - Tellurium compoundsUncontrolled terms: Femtoseconds - Optical Kerr gate - Super continuum - Tellurite glass - Three dimensional imagingClassification Code: 482.2.1 Gems - 741 Light, Optics and Optical Devices - 746 Imaging Techniques - 804.1 Organic Compounds - 812.3 Glass

Database: Compendex

Design and evaluation of a pre-traveling wave deflector magnetic solenoid lens focused streak image tube

Liu, Rong1, 2, 3; Tian, Jin-Shou1; Li, Hao1, 2; Wang, Qiang-Qiang1, 2; Wang, Chao1; Wen, Wen-Long1; Lu, Yu1; Liu, Hu-Lin1; Cao, Xi-Bin1; Wang, Jun-Feng1; Xu, Xiang-Yan1; Wang, Xing1 Source: Wuli Xuebao/Acta Physica Sinica, v 63, n 5, p 058501, March 5, 2014; Language: Chinese

; ISSN: 10003290; DOI: 10.7498/aps.63.058501;

Publisher: Science PressAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China3 Xi'an Technological University, Xi'an 710032, China

Abstract: Owing to the excellent feature of ultrahigh temporal resolution, the streak image tube has been the indispensable scientific instrument for the application to measurement of ultrafast phenomena on subpicosecond time scale. In this paper, a new femtosecond streak image tube with both high temporal and spatial resolution is designed. To improve its integrated performance, a pair of traveling wave deflectors is located before a magnetic solenoid lens in the tube, which minimizes the electron transit time from anode to deflection plates and therefore reduces time dispersion and space charge effects. Using CST microwave studio finite element method, bandwidth and deflection sensitivity of traveling wave deflector have been studied numerically. The result shows that the wide bandwidth of the traveling wave deflectors designed is beneficial to slow down the electrical deflecting pulse to match the beam velocity in a wide frequency range, which can improve the deflection sensitivity. After tracing the trajectory of electrons and calculating the modulation transform function, we get temporal resolution of 220 fs and spatial resolution above 100 lp/mm. Based on the aberration theory, the aberration formulas of electron trajectory are deduced, which systematically evaluate the imaging quality of streak image tube with modulation transfer function. Finally, static experiment is carried out, and the result shows that the static spatial resolution is better than 35 lp/mm. © 2014 Chinese Physical Society. (14 refs.)Main Heading: SolenoidsControlled terms: Bandwidth - Image resolution - ModulationUncontrolled terms: Deflection sensitivities - Design and evaluations - Electron transit time - Solenoid lens - Streak image tube - Subpicosecond time scale - Temporal resolution - Traveling waveClassification Code: 704.1 Electric Components - 716 Telecommunication; Radar, Radio and Television - 716.1 Information Theory and Signal Processing - 717 Optical Communication - 718 Telephone Systems and Related Technologies; Line Communications - 741 Light, Optics and Optical Devices - 742 Cameras and Photography

Database: Compendex

Group sparse reconstruction for image segmentation

Lu, Xiaoqiang1; Li, Xuelong1 Source: Neurocomputing, v 136, p 41-48, July 20, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2014.01.034;

Abstract: Image segmentation is a fundamental problem in computer vision and image analysis. Specially, the segmentation of medical images can assist doctors in making decisions. Due to the lack of distinctive features to describe the boundary of an organ and match function with high performance for features, medical image segmentation is difficult to be achieved with high accuracy. In this paper, an one-class classifier is proposed as the match function to decide whether the pixel belongs to the boundary or not. The proposed method is comprised of two steps. At first, a feature vector space is built with the gradient feature and its statistical information in the training stage. In the test image, a feature vector of one candidate probably being located on the boundary is reconstructed by sparse coding with the feature vector space. After reconstruction, the candidate is classified belonging to boundary or non-boundary via the reconstruction based one-class classifier. Then, in order to maintain the consistency between the candidates which are neighbors to each other, the neighboring candidates are coded using group lasso with the same dictionary. Compared to the traditional methods, the proposed one has three advantages. Firstly, it solves the non-Gaussian distribution problem of the positive samples. Secondly, it avoids large variation among the negative samples. Thirdly, the relationship of the neighboring candidates is considered and used in classification, which is ignored in other methods. The proposed method is validated on 52 MR images of prostate and outperforms Mahalanobis distance, which is considered as one of the state-of-the-art match functions. The experimental results show that the segmentation accuracy can be significantly improved by the proposed method with one-class classification. © 2014 Elsevier B.V. (31 refs.)Main Heading: Image segmentationControlled terms: Face recognition - Magnetic resonance imaging - Medical image processing - Vector spacesUncontrolled terms: Active Shape Models - Group lassos - Non-gaussian distribution - One-class Classification - One-class classifier - Prostate segmentation - Segmentation of medical images - Statistical informationClassification Code: 716 Telecommunication; Radar, Radio and Television - 723.2 Data Processing and Image Processing - 746 Imaging Techniques - 921 Mathematics

Database: Compendex

Efficient dictionary learning for visual categorization

Tang, Jun1; Shao, Ling2; Li, Xuelong3 Source: Computer Vision and Image Understanding, v 124, p 71-78, July 2014

; ISSN: 10773142, E-ISSN: 1090235X; DOI: 10.1016/j.cviu.2014.02.007;

Database: Compendex

Alternatively constrained dictionary learning for image superresolution

Lu, Xiaoqiang1; Yuan, Yuan1; Yan, Pingkun1 Source: IEEE Transactions on Cybernetics, v 44, n 3, p 366-377, March 2014

; ISSN: 21682267; DOI: 10.1109/TCYB.2013.2256347; Article number: 6512593;

Publisher: Institute of Electrical and Electronics Engineers Inc.Author affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Center for Optical Imagery Analysis and Learning, Xi'an Institute of Optics and Precision Mechanics, Xi'an 710119, China

Abstract: Dictionaries are crucial in sparse coding-based algorithm for image superresolution. Sparse coding is a typical unsupervised learning method to study the relationship between the patches of high-and low-resolution images. However, most of the sparse coding methods for image superresolution fail to simultaneously consider the geometrical structure of the dictionary and the corresponding coefficients, which may result in noticeable superresolution reconstruction artifacts. In other words, when a low-resolution image and its corresponding high-resolution image are represented in their feature spaces, the two sets of dictionaries and the obtained coefficients have intrinsic links, which has not yet been well studied. Motivated by the development on nonlocal self-similarity and manifold learning, a novel sparse coding method is reported to preserve the geometrical structure of the dictionary and the sparse coefficients of the data. Moreover, the proposed method can preserve the incoherence of dictionary entries and provide the sparse coefficients and learned dictionary from a new perspective, which have both reconstruction and discrimination properties to enhance the learning performance. Furthermore, to utilize the model of the proposed method more effectively for single-image superresolution, this paper also proposes a novel dictionary-pair learning method, which is named as two-stage dictionary training. Extensive experiments are carried out on a large set of images comparing with other popular algorithms for the same purpose, and the results clearly demonstrate the effectiveness of the proposed sparse representation model and the corresponding dictionary learning algorithm. © 2014 IEEE. (56 refs.)Main Heading: Image codingControlled terms: Algorithms - GeometryUncontrolled terms: Dictionary learning algorithms - Dictionary trainings - Geometrical structure - Image super-resolution - Manifold learning - Self-similarities - Super-resolution reconstruction - Unsupervised learning methodClassification Code: 741 Light, Optics and Optical Devices - 921 Mathematics

Database: Compendex

Controllable synthesis of monodisperse CaF<inf>2</inf> microsphere and the investigation on luminous performance of CaF<inf>2</inf>:Ce3+/Tb 3+

Sun, X.1; Hu, X.1, 2; Fan, J.3; Zhan, S.1; Wang, Y.1; Wang, Z.1; Sun, Q.1; Hao, Y.1 Source: Technical Proceedings of the 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014, v 1, p 164-167, 2014, Technical Proceedings of the 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014; ISBN-13: 9781482258264; Conference: Nanotechnology 2014: Graphene, CNTs, Particles, Films and Composites - 2014 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2014, June 15, 2014 - June 18, 2014; Sponsor: ACCT Canada; Aerojet Rocketdyne; American University in Cairo; Angel Capital Association; Angel Venture Forum; et al.;

Publisher: Nano Science and Technology InstituteAuthor affiliation: 1 School of Physics, Northwest University, 710069, China2 State Key Laboratory of Transient Optics and Technology, Xi'an Institute of Optics and Precision Materials, Chinese Academy of Science, Xi'an 710068, China3 School of Chemical Engineering, Xi'an, 710069, China

Abstract: In this paper, highly uniform and well-dispersed CaF<inf>2</inf> microsphere with tunable particles size have been successfully synthesized by a facile hydrothermal process using ethylenediaminetetraacetic acid disodium as a complexing reagent. The XRD results indicated that the as-prepared microspheres were of cubic phases and had good crystallinity and purity. The TEM and SEM results reveal that monodisperse and uniform hollow sphere with rough surfaces can be prepared by this approach. In addition, Ce3+/Tb 3+-codoped CaF<inf>2</inf> sphere can be prepared similarly. Excitation and emission spectra are shown that the samples can absorb ultraviolet light and emit light at 335 nm. In the emission spectrum, it is clear that emission intensity of Ce<inf>3+</inf> decreases with increasing Tb<inf>3+</inf>, it shows that efficient energy transfer from Ce3+ to Tb3+ may occur. It significantly improves the absorption range and intensity of the samples. That is extremely useful and has potential application value in display, light, laser, optical information transfer, scintillator and optoelectronic devices. (6 refs.)Main Heading: Nanocomposite filmsControlled terms: Display devices - Emission spectroscopy - Energy transfer - Ethylenediaminetetraacetic acid - Light - Luminescence - Metal ions - Microspheres - Nanotechnology - Optoelectronic devices - Semiconductor dopingUncontrolled terms: Controllable synthesis - Efficient energy transfer - Excitation and emission spectra - Hollow microsphere - Hydrothermal process - Optical information - Rare earth ionsClassification Code: 533 Ore Treatment and Metal Refining - 641.2 Heat Transfer - 712.1 Semiconducting Materials - 722.2 Computer Peripheral Equipment - 741.1 Light/Optics - 741.3 Optical Devices and Systems - 761 Nanotechnology - 804.1 Organic Compounds - 818 Rubber and Elastomers

Database: Compendex

Burst-mode operation of a 650GHz mode locked laser based on a high order microring resonator

Jin, Lin1; Pasquazi, Alessia2; Tsang, K.S.3; Ho, Victor1; Peccianti, Marco2; Caspani, Lucia4; Ferrera, Marcello5; Pun, E.Y.B.6; Wei, P.K.A.3; Little, Brent E.7; Moss, David J.8; Morandotti, Roberto4; Chu, Sai T.1 Source: 2014 OptoElectronics and Communication Conference, OECC 2014 and Australian Conference on Optical Fibre Technology, ACOFT 2014, p 70-72, 2014, 2014 OptoElectronics and Communication Conference, OECC 2014 and Australian Conference on Optical Fibre Technology, ACOFT 2014; ISBN-13: 9781922107213; Article number: 6888000; Conference: 19th OptoElectronics and Communications Conference, OECC 2014 and the 39th Australian Conference on Optical Fibre Technology, ACOFT 2014, July 6, 2014 - July 10, 2014; Sponsor: The University of Melbourne;

Publisher: IEEE Computer SocietyAuthor affiliation: 1 Department of Physics and Materials Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong2 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton, BN1 9QH, United Kingdom3 Photonics Research Center, Department of Electronic and Information Engineering, Hong Kong Polytechnic University, Hung Hom, Hong Kong4 INRS - Énergie, Matériaux et Télé communications, 1650 Blvd Lionel Boulet, Varennes, QC J3X 1S2, Canada5 School of Engineering and Physical Sciences, Heriot-Watt University, David Brewster Building, Edinburgh, EH14 4AS, United Kingdom6 Department of Electrical Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong7 Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an, China8 Institute of Photonics and Optical Science (IPOS), School of Physics, University of Sydney, Sydney, NSW 2006, Australia

Abstract: We demonstrated a new regime of operation for ultrafast mode-locked lasers that we termed "burst-mode" modelocking. By exploiting an integrated 11th order micro-ring resonator, our scheme achieves stable operation resulting in a mode-locked train of pulses at 650 GHz with a burst mode envelope of 40 ps at 7.12 MHz. © 2014 Engineers Australia. (12 refs.)Main Heading: Optoelectronic devicesControlled terms: Locks (fasteners) - Mode-locked fiber lasers - Optical communication - Optical fibers - Optical resonatorsUncontrolled terms: Burst-mode operation - Microring resonator - Mode-locked - Mode-locked laser - Modelocking - Regime of operation - Stable operation - Ultra-fastClassification Code: 601.3 Mechanisms - 717.1 Optical Communication Systems - 741.1.2 Fiber Optics - 741.3 Optical Devices and Systems - 744.1 Lasers, General

Database: Compendex

Low loss and high birefringence Topas photonic bandgap fiber at terahertz frequency

Wang, Dou-Dou1; Wang, Li-Li2; Zhang, Tao1; Xie, You1 Source: Guangzi Xuebao/Acta Photonica Sinica, v 43, n 6, June 2014; Language: Chinese

; ISSN: 10044213; DOI: 10.3788/gzxb20144306.0606002; Article number: 0606002;

Publisher: Chinese Optical SocietyAuthor affiliation: 1 College of Science, Xi'an University of Science and Technology, Xi'an 710054, China2 State Key Laboratory of Transient Optics and Photonics, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China

Abstract: A photonic bandgap fiber was designed based on the novel Terahertz low-loss material Topas cyclic olefin copolymer. Fiber cladding was formed by arranging hexagonal air holes with rounded corners in triangular lattice pattern in the background of Topas. A rhombic hollow-core with rounded corners was formed by omitting four central air holes of the cladding structure. Propagation properties in the terahertz band of the fiber were investigated by using the finite element method. Numerical results indicate the fiber has a photonic bandgap within a broadband area about 0.3 THz around 1.5 THz, and THz wave is welled confined in the air core. Birefringence of the order of 10-3 was obtained. Loss of the x-and y-polarized fundamental modes is less than 0.1 cm-1 within 1.4~1.6 THz, and reaches the minimum value of 0.0291 cm-1 and 0.0287 cm-1 at 1.53 THz and 1.5 THz, respectively. Structure of designed terahertz Topas photonic bandgap fiber is simple, feasible for fabrication and bendable because of the relatively small diameter. (17 refs.)Main Heading: Photonic bandgap fibersControlled terms: Birefringence - Copolymers - Fibers - Finite element method - Losses - Olefins - Optical fiber fabrication - Photonic crystal fibers - Spontaneous emission - Terahertz wavesUncontrolled terms: Cladding structures - Cyclic Olefin Copolymers - Hexagonal air holes - High birefringence - Propagation properties - Tera Hertz - Terahertz frequencies - Triangular latticeClassification Code: 711 Electromagnetic Waves - 741.1 Light/Optics - 741.1.2 Fiber Optics - 804.1 Organic Compounds - 812 Ceramics, Refractories and Glass - 812.3 Glass - 815.1 Polymeric Materials - 817 Plastics and Other Polymers: Products and Applications - 911.2 Industrial Economics - 921.6 Numerical Methods - 951 Materials Science

Database: Compendex

Dynamical focus position detection of single pulse high power laser system

Zhao, Juanning1, 2; Dong, Xiaona1; Da, Zhengshang1; Li, Hongguang1 Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering, v 43, n 6, p 1925-1929, June 2014; Language: Chinese

; ISSN: 10072276;

Abstract: To tackle the problem that traditional focus measure technologies cannot measure the focus shifting caused by thermal distortion in single pulse high power laser system, a system, composed with double vertical wedge groups producing array spots, can make instantly focus measure available. Two pairs of wedge -mirror groups which are placed vertically to each other are utilized as beam splitting system in this system. All those rays are finally detected by a detector, and formed a matric of spots with various sizes. Through single detection of spots matrix, various focus position shifts and the focus shifting measurement of the high power laser with single shot are obtained. After theoretical analyzing, software simulating and experiment testing, this technique has the advantages such as the adjustable detecting accuracy and range, good disperse quality, and the ability of restraining the effect of parasitic light. (7 refs.)Main Heading: High power lasersControlled terms: DetectorsUncontrolled terms: Beam splitting - Double wedge - Experiment testing - Focal spot - Focus positions - High-power laser systems - Parasitic light analysis - Thermal distortionsClassification Code: 744.1 Lasers, General - 914 Safety Engineering

Database: Compendex

GaAs film for photon-enhanced thermionic emission solar harvesters

Tang, Weidong1, 2; Yang, Wenzheng3; Yang, Yang1, 2; Sun, Chuandong3; Cai, Zhipeng1, 2 Source: Materials Science in Semiconductor Processing, v 25, p 143-147, September 2014

; ISSN: 13698001; DOI: 10.1016/j.mssp.2013.10.009;

Publisher: Elsevier LtdAuthor affiliation: 1 State Key Laboratory of Transient Optics and Photonics, Xi'an, China2 University of Chinese Academy of Sciences, Beijing, China3 Key Laboratory of Ultrafast Photoelectric Diagnostics Technology, Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China

Abstract: A novel concept for solar electricity generation named photon-enhanced thermionic emission (PETE) was recently proposed for harvesting solar photonic and thermionic energies simultaneously. Comparative investigations showed that the conversion efficiency of PETE can theoretically exceed 40%. In this paper, an electric field-assisted PETE experiment was carried out to demonstrate the possibility of using GaAs epitaxial films in PETE solar devices. The solar photonic and thermionic effects were simulated by a red light-emitting diode array and a heat resistor, respectively. Surface electron affinity was decreased by an electric field instead of Cs/Cs-O coating. The experimental results agreed with calculated values, and a distinct enhancement was observed in the thermionic emission produced by photoexcitation compared with thermionic field emission produced by an illuminated sample and the sample emission obtained in the dark. (15 refs.)Main Heading: Thermionic emissionControlled terms: Electric fields - Electron affinity - Field emission - Gallium arsenide - Light emitting diodes - Photons - Semiconducting galliumUncontrolled terms: Calculated values - GaAs films - PETE - Sample emission - Solar electricity - Thermionic effects - Thermionic energies - Thermionic field emissionClassification Code: 701.1 Electricity: Basic Concepts and Phenomena - 712.1.1 Single Element Semiconducting Materials - 712.2 Thermionic Materials - 741.1 Light/Optics - 801 Chemistry - 804 Chemical Products Generally - 932 High Energy Physics; Nuclear Physics; Plasma Physics

Database: Compendex

A comprehensive survey to face hallucination

Wang, Nannan1; Tao, Dacheng2; Gao, Xinbo1; Li, Xuelong3; Li, Jie1 Source: International Journal of Computer Vision, v 106, n 1, p 9-30, January 2014

; ISSN: 09205691, E-ISSN: 15731405; DOI: 10.1007/s11263-013-0645-9;

Publisher: Springer NetherlandsAuthor affiliation: 1 VIPS Lab, School of Electronic Engineering, Xidian University, Xi'an 710071, China2 Centre for Quantum Computation and Intelligent Systems, Faculty of Engineering and Information Technology, University of Technology Sydney, 235 Jones Street, Ultimo NSW 2007, Australia3 State Key Laboratory of Transient Optics and Photonics, Center for OPTical IMagery Analysis and Learning (OPTIMAL), Chinese Academy of Sciences, Xi'an 710119 Shaanxi, China

Abstract: This paper comprehensively surveys the development of face hallucination (FH), including both face super-resolution and face sketch-photo synthesis techniques. Indeed, these two techniques share the same objective of inferring a target face image (e.g. high-resolution face image, face sketch and face photo) from a corresponding source input (e.g. low-resolution face image, face photo and face sketch). Considering the critical role of image interpretation in modern intelligent systems for authentication, surveillance, law enforcement, security control, and entertainment, FH has attracted growing attention in recent years. Existing FH methods can be grouped into four categories: Bayesian inference approaches, subspace learning approaches, a combination of Bayesian inference and subspace learning approaches, and sparse representation-based approaches. In spite of achieving a certain level of development, FH is limited in its success by complex application conditions such as variant illuminations, poses, or views. This paper provides a holistic understanding and deep insight into FH, and presents a comparative analysis of representative methods and promising future directions. © 2013 Springer Science+Business Media New York. (159 refs.)Main Heading: SurveysControlled terms: Bayesian networks - Inference engines - Intelligent systems - Optical resolving powerUncontrolled terms: Comparative analysis - Complex applications - Face hallucination - Face sketch-photo synthesis - Face super-resolution - Image interpretation - Image transformations - Low-resolution face imagesClassification Code: 405.3 Surveying - 723.4 Artificial Intelligence - 723.4.1 Expert Systems - 741.1 Light/Optics - 921.4 Combinatorial Mathematics, Includes Graph Theory, Set Theory

Database: Compendex

Learning to resize image

Wang, Qi1; Yuan, Yuan2 Source: Neurocomputing, v 131, p 357-367, May 5, 2014

; ISSN: 09252312, E-ISSN: 18728286; DOI: 10.1016/j.neucom.2013.10.007;

Abstract: Content-aware image resizing has been a promising theme in the communities of image processing and computer vision. To the best of our knowledge, most existing methods for image resizing are unsupervised. These unsupervised methods may either fail to protect the interesting regions or cause distortion of the image structure. This paper presents a novel learning based method for seam carving by incorporating the learned boundary of the important content. Specifically, a novel boundary model of the region of interest (ROI) is learned on a set of training images at first. Then the boundary of an input image is utilized as a key prior in performing seam carving to obtain the target image. The proposed method for image resizing can generate much less seams cutting through the ROI compared with previous efforts toward the same goal. Thus, the desirable regions can be preserved in the target image and the structural consistency of the input image is naturally maintained. Experiments on two publicly available data sets demonstrate the effectiveness of the proposed method. © 2014. (47 refs.)Main Heading: Image segmentationControlled terms: Computer applications - Image processing - Learning systems - Neural networksUncontrolled terms: Boundary - Content-aware image resizing - Image processing and computer vision - Image resizing - Learning-based methods - Saliency - Seam carving - The region of interest (ROI)Classification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 741.1 Light/Optics

Database: Compendex

Integrated frequency comb source of heralded single photons

Reimer, Christian1; Caspani, Lucia1; Clerici, Matteo1, 2; Ferrera, Marcello1, 2; Kues, Michael1; Peccianti, Marco1, 3; Pasquazi, Alessia1, 3; Razzari, Luca1; Little, Brent E.4; Chu, Sai T.5; Moss, David J.1, 6; Morandotti, Roberto1 Source: Optics Express, v 22, n 6, p 6535-6546, 41722; E-ISSN: 10944087; DOI: 10.1364/OE.22.006535;

Publisher: Optical Society of AmericaAuthor affiliation: 1 INRS-EMT, 1650 Boulevard Lionel-Boulet, Varennes, QC J3X 1S2, Canada2 School of Engineering and Physical Sciences, Heriot-Watt University, SUPA, Edinburgh EH14 4AS, United Kingdom3 Department of Physics and Astronomy, University of Sussex, Falmer, Brighton BN1 9QH, United Kingdom4 Xi'An Institute of Optics and Precision Mechanics of CAS, Xi'an, China5 University of Hong Kong, Department of Physics and Material Science, Tat Chee Avenue, Hong Kong, Hong Kong6 School of Electrical and Computer Engineering, RMIT University, Melbourne, VIC, 3001, Australia

Abstract: We report an integrated photon pair source based on a CMOScompatible microring resonator that generates multiple, simultaneous, and independent photon pairs at different wavelengths in a frequency comb compatible with fiber communication wavelength division multiplexing channels (200 GHz channel separation) and with a linewidth that is compatible with quantum memories (110 MHz). It operates in a self-locked pump configuration, avoiding the need for active stabilization, making it extremely robust even at very low power levels. © 2014 Optical Society of America. (43 refs.)Main Heading: Source separationControlled terms: Optical communication - PhotonsUncontrolled terms: Active stabilization - Channel separation - CMOS Compatible - Fiber communications - Frequency combs - Heralded single photons - Microring resonator - Pump configurationClassification Code: 716.1 Information Theory and Signal Processing - 717.1 Optical Communication Systems - 741.1 Light/Optics

Database: Compendex

An Ytterbium-doped fiber laser with dark and Q-switched pulse generation using graphene-oxide as saturable absorber

Zhao, Junqing1; Wang, Yonggang2; Yan, Peiguang1; Ruan, Shuangchen1; Tsang, Yuen3; Zhang, Gelin1; Li, Huiquan1 Source: Optics Communications, v 312, p 227-232, 2014

; ISSN: 00304018; DOI: 10.1016/j.optcom.2013.09.038;

Publisher: ElsevierAuthor affiliation: 1 Shenzhen Key Laboratory of Laser Engineering, Shenzhen University, Shenzhen 518060, Guangdong, China2 State Key Laboratory of Transient Optics and Photonics, Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China3 Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong, Hong Kong

Abstract: We demonstrate an ytterbium-doped fiber (YDF) laser being able to generate dark pulses and Q-switched pulses by using a graphene oxide (GO) based composite as saturable absorber (SA). These operation regimes are realized for the first time in a 1-μm band fiber laser as far as our best knowledge. In the fabrication of GO based saturable absorber (GOSA), a vertical evaporation process is included, which results in a GO concentration and thickness variable SA. The generated dark pulse has pulse duration in ns-scale. In the Q-switched operation, pulses with durations from 5.321 μs to 2.655 μs and repetition rates from 28.47 kHz to 58.95 kHz can be obtained as the launched pump power is changed. The transition from the dark pulse to Q-switched operations can be clearly seen as the pump power is increased to a certain value. The radio frequency (RF) and optical spectrum variations with respect to the change of pump power have also been analyzed in detail. © 2013 Elsevier B.V. (22 refs.)Main Heading: Pulse generatorsControlled terms: Fiber lasers - Graphene - Optical pumping - Pulse repetition rate - Q switching - Saturable absorbers - YtterbiumUncontrolled terms: Dark pulse - Evaporation process - Graphene oxides - Launched pump power - Q-switched - Q-switched operation - Ytterbium doped fibers - Ytterbium-doped fiber lasersClassification Code: 804 Chemical Products Generally - 761 Nanotechnology - 744 Lasers - 741.1.2 Fiber Optics - 741.1 Light/Optics - 713.4 Pulse Circuits - 547.2 Rare Earth Metals

Database: Compendex

Stray light analysis during non-collinear sum-frequency generation

Yuan, Suochao1; Gao, Limin1; Li, Dongjian1; Zhao, Juanning1, 2 Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams, v 26, n 1, January 2014; Language: Chinese

; ISSN: 10014322; DOI: 10.3788/HPLPB201426.011001; Article number: 011001;

Publisher: Editorial Office of High Power Laser and Particle BeamsAuthor affiliation: 1 Department of Advanced Optics Instruments, Xi'an Institute of Optics and Precision Mechanic, Chinese Academy of Sciences, Xi'an 710119, China2 University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: We analyze the stray light caused by surface scattering of the sum-frequency crystal in third-order correlation measurement and its influence on the contrast of the sum-frequency light. Besides, the expression of the stray light caused by surface scattering is given. When the surface roughness is 1% of the laser wavelength, the intensity of stray light reaches about 10-8. And the rougher the surface is, the more stray light it causes. (16 refs.)Main Heading: Stray lightControlled terms: Interferometry - Plasma interactions - Surface roughness - Surface scatteringUncontrolled terms: Correlation measurement - Laser wavelength - Sum frequency - Sum-frequency generation - Sum-frequency lights - Third-orderClassification Code: 741.1 Light/Optics - 931 Classical Physics; Quantum Theory; Relativity - 931.2 Physical Properties of Gases, Liquids and Solids - 932.3 Plasma Physics - 941.4 Optical Variables Measurements

Database: Compendex

Multi-frame super-resolution reconstruction algorithm based on diffusion tensor regularization term

Zhao, Xiao Dong1, 2; Zhou, Zuo Feng1; Cao, Jian Zhong1; Ren, Long1; Liu, Guang Sen1; Wang, Hua1; Wu, Deng Shan1; Tan, Jia Hai1 Source: Applied Mechanics and Materials, v 543-547, p 2828-2832, 2014, Vehicle, Mechatronics and Information Technologies II

; ISSN: 16609336, E-ISSN: 16627482; ISBN-13: 9783038350606; DOI: 10.4028/www.scientific.net/AMM.543-547.2828; Conference: International Conference on Vehicle and Mechanical Engineering and Information Technology, VMEIT 2014, February 19, 2014 - February 20, 2014; Sponsor: INTIEA Information and Engineering; Scientific.Net; Trans Tech publications inc.; National Institute of Technology Rourkela; Universitatea Politehnica Din Bucuresti; et al;

Publisher: Trans Tech Publications LtdAuthor affiliation: 1 Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an 710119, China2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China

Abstract: This paper presents a multi-frame super-resolution (SR) reconstruction algorithm based on diffusion tensor regularization term. Firstly, L1-norm structure is used as data fidelity term, anisotropic diffusion equation with directional smooth characteristics is introduced as a prior knowledge to optimize reconstruction result. Secondly, combined with shock filter, SR reconstruction energy functional is established. Finally, Euler-Lagrange equation based on nonlinear diffusion model is exported. Simulation results validate that the proposed algorithm enhances image edges and suppresses noise effectively, which proves better robustness. © (2014) Trans Tech Publications, Switzerland. (10 refs.)Main Heading: Edge detectionControlled terms: Algorithms - Anisotropy - Image reconstruction - Information technology - Optical resolving powerUncontrolled terms: Anisotropic diffusion equations - Diffusion tensor - Euler-Lagrange equations - Nonlinear diffusion model - PDE - Reconstruction algorithms - Reconstruction energy - Super-resolution reconstructionClassification Code: 723 Computer Software, Data Handling and Applications - 741 Light, Optics and Optical Devices - 741.1 Light/Optics - 903 Information Science - 921 Mathematics - 931.2 Physical Properties of Gases, Liquids and Solids

Database: Compendex

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