2024

• Record 145 of
  
  Title:Consumer Camera Demosaicking and Denoising With a Collaborative Attention Fusion Network
  
  Author(s):Yuan, Nianzeng; Li, Junhuai; Sun, Bangyong
  Source: IEEE TRANSACTIONS ON CONSUMER ELECTRONICS  Volume: 70  Issue: 1  DOI: 10.1109/TCE.2023.3342035  Published: 2024  
  Abstract:For the consumer cameras with Bayer filter array, raw color filter array (CFA) data collected in real-world is sampled with signal-dependent noise. Various joint denoising and demosaicking (JDD) methods are utilized to reconstruct full-color and noise-free images. However, some artifacts (e.g., remaining noise, color distortion, and fuzzy details) still exist in the reconstructed images by most JDD models, mainly due to the highly related challenges of low sampling rate and signal-dependent noise. In this paper, a collaborative attention fusion network (CAF-Net), with two key modules, is proposed to solve this issue. Firstly, a multi-weight attention module is proposed to efficiently extract image features by realizing the interaction of spatial, channel, and pixel attention mechanisms. By designing a local feedforward network and mask convolution aggregation of multiple receptive fields, we then propose an effective dual-branch feature fusion module, which enhances image details and spatial correlation. Accordingly, the proposed two modules significantly facilitate our CAF-Net to recover a high-quality image, by accurately inferring the correlations of color, noise, and the spatial distribution of the CFA data. Extensive experiments on demosaicking, synthetic, and real image JDD tasks prove that the proposed CAF-Net can achieve advanced performance in terms of objective evaluation index metrics and visual perception.
  Accession Number:
  ISSN: 0098-3063
  eISSN: 1558-4127
• Record 146 of
  
  Title:Duplex-Hierarchy Representation Learning for Remote Sensing Image Classification
  
  Author(s):Yuan, Xiaobin; Zhu, Jingping; Lei, Hao; Peng, Shengjun; Wang, Weidong; Li, Xiaobin
  Source: SENSORS  Volume: 24  Issue: 4  DOI: 10.3390/s24041130  Published: 2024  
  Abstract:Remote sensing image classification (RSIC) is designed to assign specific semantic labels to aerial images, which is significant and fundamental in many applications. In recent years, substantial work has been conducted on RSIC with the help of deep learning models. Even though these models have greatly enhanced the performance of RSIC, the issues of diversity in the same class and similarity between different classes in remote sensing images remain huge challenges for RSIC. To solve these problems, a duplex-hierarchy representation learning (DHRL) method is proposed. The proposed DHRL method aims to explore duplex-hierarchy spaces, including a common space and a label space, to learn discriminative representations for RSIC. The proposed DHRL method consists of three main steps: First, paired images are fed to a pretrained ResNet network for extracting the corresponding features. Second, the extracted features are further explored and mapped into a common space for reducing the intra-class scatter and enlarging the inter-class separation. Third, the obtained representations are used to predict the categories of the input images, and the discrimination loss in the label space is minimized to further promote the learning of discriminative representations. Meanwhile, a confusion score is computed and added to the classification loss for guiding the discriminative representation learning via backpropagation. The comprehensive experimental results show that the proposed method is superior to the existing state-of-the-art methods on two challenging remote sensing image scene datasets, demonstrating that the proposed method is significantly effective.
  Accession Number: 1130
  ISSN:
  eISSN: 1424-8220
• Record 147 of
  
  Title:Study on the construction of twisted cosine partially coherent beams and their propagation characteristics
  
  Author(s):Zhang, Shaohua; Zhou, Yuan; Chai, Yutong; Qu, Jun
  Source: AIP ADVANCES  Volume: 14  Issue: 2  DOI: 10.1063/5.0186514  Published: 2024  
  Abstract:We propose a novel Schell model source for generating twisted partially coherent beams with an initial radius of curvature, which is called a twisted flat-topped cosine Gaussian Schell-model (TFCGSM) source. The TFCGSM beam comprises a wavefront phase and a flat-top structure, with the source degree of coherence determined by two cosine functions. Based on the Huygens-Fresnel principle, the general analytical expression of the cross-spectral density function of the TFCGSM beam propagating through the paraxial ABCD optical system is derived, and then its propagation properties are studied. The results show that the conversion of the array of the beam and the non-uniform structure can be realized by adjusting the parameters in the source plane. As the propagation distance of the TFCGSM beam increases, it rotates around the axis and increases the intensity of the array distribution. Surprisingly, the initial radius of curvature can cause the beam to rotate. The unique shape and properties of the TFCGSM beam create new possibilities for optical communication and enhanced optical functions. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(http://creativecommons.org/licenses/by/4.0/).
  Accession Number: 25235
  ISSN:
  eISSN: 2158-3226
• Record 148 of
  
  Title:A Snapshot Multi-Spectral Demosaicing Method for Multi-Spectral Filter Array Images Based on Channel Attention Network
  
  Author(s):Zhang, Xuejun; Dai, Yidan; Zhang, Geng; Zhang, Xuemin; Hu, Bingliang
  Source: SENSORS  Volume: 24  Issue: 3  DOI: 10.3390/s24030943  Published: 2024  
  Abstract:Multi-spectral imaging technologies have made great progress in the past few decades. The development of snapshot cameras equipped with a specific multi-spectral filter array (MSFA) allow dynamic scenes to be captured on a miniaturized platform across multiple spectral bands, opening up extensive applications in quantitative and visualized analysis. However, a snapshot camera based on MSFA captures a single band per pixel; thus, the other spectral band components of pixels are all missed. The raw images, which are captured by snapshot multi-spectral imaging systems, require a reconstruction procedure called demosaicing to estimate a fully defined multi-spectral image (MSI). With increasing spectral bands, the challenge of demosaicing becomes more difficult. Furthermore, the existing demosaicing methods will produce adverse artifacts and aliasing because of the adverse effects of spatial interpolation and the inadequacy of the number of layers in the network structure. In this paper, a novel multi-spectral demosaicing method based on a deep convolution neural network (CNN) is proposed for the reconstruction of full-resolution multi-spectral images from raw MSFA-based spectral mosaic images. The CNN is integrated with the channel attention mechanism to protect important channel features. We verify the merits of the proposed method using 5 x 5 raw mosaic images on synthetic as well as real-world data. The experimental results show that the proposed method outperforms the existing demosaicing methods in terms of spatial details and spectral fidelity.
  Accession Number: 943
  ISSN:
  eISSN: 1424-8220
• Record 149 of
  
  Title:High-performance architecture for real-time high-definition short-wave infrared streaming video processing and its field programmable gate array prototype
  
  Author(s):Zhou, Feng; Chen, Zhiqiang; Xie, Qingsheng; Kong, Fanzi; Chen, Yaohong; Wang, Huawei
  Source: OPTICAL ENGINEERING  Volume: 63  Issue: 2  DOI: 10.1117/1.OE.63.2.023103  Published: 2024  
  Abstract:. Image detail enhancement is critical to the performance of short-wave infrared (SWIR) imaging systems. Recently, the requirement for real-time processing of high-definition (HD) SWIR video has shown rapid growth. Nevertheless, the research on field programmable gate array (FPGA) implementation of HD SWIR streaming video processing architecture is relatively few. This work proposes a real-time FPGA architecture of SWIR video enhancement by combining the difference of Gaussian filter and plateau equalization. To accelerate the algorithm and reduce memory bandwidth, two efficient key architectures, namely edge information extraction and equalization and remapping architecture, are proposed to sharpen edges and improve dynamic range. The experimental results demonstrated that the proposed architecture achieved a real-time processing of 1280 x 1024@60Hz with 2.7K lookup tables, 2.5K Slice Reg, and about 350 kb of block RAM consumption, and their utilization reached 12.5%, 19.2%, and 12.5% for the XC7A200T FPGA board, respectively. Moreover, the proposed architecture is fully pipelined and synchronized to the pixel clock of output video, meaning that it can be seamlessly integrated into diverse real-time video processing systems.
  Accession Number:
  ISSN: 0091-3286
  eISSN: 1560-2303
• Record 150 of
  
  Title:Process optimization of infrared chalcogenide glass based on the scattering detection
  
  Author(s):Tang, Yuxin; Xu, Yantao; Cui, Xiaoxia; Zhang, Jinchang; Li, Man; Xiao, Xusheng; Yan, Mengmeng; Guo, Haitao
  Source: CERAMICS INTERNATIONAL  Volume: 50  Issue: 5  DOI: 10.1016/j.ceramint.2023.12.020  Published: 2024  
  Abstract:Chalcogenide glasses with less optical losses are highly demanded as optical materials for micro lense, waveguide and fiber devices. However, it is still challengeable to reduce the optical losses in infrared chalcogenide glasses with opaque visible light. Herein, an improved 3D distribution of scattering sources is established in this study to test and compare the concentration and distribution of defects in As38S62, Ge28Sb12Se60 and As40Se60 chalcogenide glasses. Furthermore, by comparing the scattering images of serial As40Se60 glass prepared under various melting, quenching and annealing temperatures, the preparation process was optimized to reduce its scattering loss. In addition, this study introduced a scheme that could be widely applied to optimize processing of other infrared glasses and devices glass to reduce their scattering losses.
  Accession Number:
  ISSN: 0272-8842
  eISSN: 1873-3956
• Record 151 of
  
  Title:Reduced eye gaze fixation during emotion recognition among patients with temporal lobe epilepsy
  
  Author(s):Huang, Kailing; Tian, Ziwei; Zhang, Qiong; Yang, Haojun; Wen, Shirui; Feng, Jie; Tang, Weiting; Wang, Quan; Feng, Li
  Source: JOURNAL OF NEUROLOGY  Volume: 271  Issue: 5  DOI: 10.1007/s00415-024-12202-w  Published: 2024  
  Abstract:ObjectivesTo investigate the facial scan patterns during emotion recognition (ER) through the dynamic facial expression task and the awareness of social interference test (TASIT) using eye tracking (ET) technology, and to find some ET indicators that can accurately depict the ER process, which is a beneficial supplement to existing ER assessment tools.MethodNinety-six patients with TLE and 88 healthy controls (HCs) were recruited. All participants watched the dynamic facial expression task and TASIT including a synchronized eye movement recording and recognized the emotion (anger, disgust, happiness, or sadness). The accuracy of ER was recorded. The first fixation time, first fixation duration, dwell time, and fixation count were selected and analyzed.ResultsTLE patients exhibited ER impairment especially for disgust (Z = - 3.391; p = 0.001) and sadness (Z = - 3.145; p = 0.002). TLE patients fixated less on the face, as evidenced by the reduced fixation count (Z = - 2.549; p = 0.011) of the face and a significant decrease in the fixation count rate (Z = - 1.993; p = 0.046). During the dynamic facial expression task, TLE patients focused less on the eyes, as evidenced by the decreased first fixation duration (Z = - 4.322; p = 0.000), dwell time (Z = - 4.083; p = 0.000), and fixation count (Z = - 3.699; p = 0.000) of the eyes.ConclusionTLE patients had ER impairment, especially regarding negative emotions, which may be attributable to their reduced fixation on the eyes during ER, and the increased fixation on the mouth could be a compensatory effect to improve ER performance. Eye-tracking technology could provide the process indicators of ER, and is a valuable supplement to traditional ER assessment tasks.
  Accession Number:
  ISSN: 0340-5354
  eISSN: 1432-1459
• Record 152 of
  
  Title:Characterization of primary silicate minerals in Earth-like bodies via Raman spectroscopy
  
  Author(s):Huang, Shuaidong; Xue, Bin; Zhao, Yiyi; Yang, Jianfeng
  Source: JOURNAL OF RAMAN SPECTROSCOPY  Volume: 55  Issue: 5  DOI: 10.1002/jrs.6657  Published: 2024  
  Abstract:The examination and identification of silicate minerals are critical for advancing our understanding of the evolutionary journey of Earth-like bodies. To facilitate an efficient and productive process, it is imperative that these minerals be detected swiftly and accurately. This study is designed to explore the relationship between varying concentrations of cations and their corresponding Raman shifts. The focus is on primary silicate minerals in Earth-like bodies, specifically olivine, pyroxene, and feldspar, utilizing data from the RRUFF database. Employing a fitting formula, we identify distinct Raman peak ranges associated with different silicate minerals. Our research covers a wide array of mineral types, including five varieties of olivine (forsterite [Mg2SiO4], fayalite [Fe2+2SiO4], tephroite [Mn2+2SiO4], monticellite [CaMgSiO4], and kirschsteinite [CaFe2+SiO4]), four types of pyroxene (ferrosilite [Fe2+2Si2O6], enstatite [Mg2Si2O6], hedenbergite [CaFe2+Si2O6], and diopside [CaMgSi2O6]), and three varieties of feldspar (alkali feldspar [KAlSi3O8], albite [NaAlSi3O8], and anorthite [CaAl2Si2O8]). The accuracy of matching Raman characteristics is exceptionally high for all olivine and pyroxene types (100%) and an impressive 86% for feldspar. The findings from this study highlight the crucial role of Raman spectroscopy in the field of silicate mineralogy and suggest significant implications for enhancing future exploration missions to Earth-like bodies. In this paper, the Raman spectral characteristics of primary minerals in Earth-like bodies were specified by using RRUFF database to analysis. The success rate in matching Raman characteristics is notably high for all olivine and pyroxene types (100%) and a commendable 86% for feldspar. The identification uses fewer peaks, resulting in a higher accuracy. image
  Accession Number:
  ISSN: 0377-0486
  eISSN: 1097-4555
• Record 153 of
  
  Title:Inverse design of high efficiency and large bandwidth power splitter for arbitrary power ratio based on deep residual network
  
  Author(s):Wen, Jin; Wu, Zhengwei; Zhang, Hui; Wang, Qian; Yu, Huimin; Zhang, Ying; Pan, Yu; Liu, Zhanzhi
  Source: OPTICAL AND QUANTUM ELECTRONICS  Volume: 56  Issue: 4  DOI: 10.1007/s11082-023-06165-x  Published: 2024  
  Abstract:In this research, we propose the deep Residual Network to realize the inverse design of a low loss 1 x 3 port power splitter with an area of 2.6 x 2.6 mu m2 on a standard silicon-on-insulator platform. Then the area is used as the inverse design region and discretized into 20 x 20 square pixels, where each pixel can be switched between the two random initial states of silicon square with and without holes. Besides, we use the direct binary search algorithm to change the state of the pixels so that the distribution of all pixels in the inverse design region reaches the optimal value of the algorithm. While training the network, inputting spectral transmission response, and using the etched hole vector positions as a label for the inverse design, it achieved an accuracy of 0.9111 and a correlation coefficient greater than 0.88 for all three ports. Finally, we demonstrated 1 x 3 power splitters with 1:2:1, 1:2:1.5, 1:3:1, and 1:3:2 distribution ratios and a more than 90% maximum transmission efficiency with bandwidth from 1450 to 1650 nm while having a low insertion loss of less than 0.45 dB. This research can be found potential applications in the design of photonic devices with high performance and small size.
  Accession Number: 512
  ISSN: 0306-8919
  eISSN: 1572-817X
• Record 154 of
  
  Title:Phase correction strategy based on structured light fringe projection profilometry
  
  Author(s):Cao, Hongyan; Qiao, Dayong; Yang, Di
  Source: OPTICS EXPRESS  Volume: 32  Issue: 3  DOI: 10.1364/OE.513572  Published: 2024  
  Abstract:Fringe projection profilometry based on structured light has been widely used in 3-D vision due to its advantages of simple structure, good robustness, and high speed. The principle of this technique is to project multiple orders of stripes on the object, and the camera captures the deformed stripe map. Phase unwrapping and depth map calculation are important steps. Still, in actual situations, phase ambiguity is prone to occur at the edges of the object. In this paper, an adaptive phase segmentation and correction (APSC) method after phase unwrapping is proposed. In order to effectively distinguish the stable area and unstable area of the phase, a boundary identification method is proposed to obtain the structural mask of the phase. A phase compensation method is proposed to improve the phase accuracy. Finally, we obtain the 3-D reconstruction result based on the corrected phase. Specific experimental results verify the feasibility and effectiveness of this method. (c) 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 155 of
  
  Title:Evaporation characteristics of Er3+-doped silica fiber and its application in the preparation of whispering gallery mode lasers
  
  Author(s):Li, Angzhen; Ward, Jonathan M.; Tian, Ke; Yu, Jibo; She, Shengfei; Hou, Chaoqi; Guo, Haitao; Chormaic, Sile Nic; Wang, Pengfei
  Source: OPTICS EXPRESS  Volume: 32  Issue: 3  DOI: 10.1364/OE.509662  Published: 2024  
  Abstract:In this work, the concentration of rare-earth ions in doped silica whispering gallery lasers (WGLs) is controlled by evaporation. The fabrication of WGLs is used to experimentally evaluate the evaporation rate (mol/mu m) and ratio (mol/mol) of erbium and silica lost from a doped fiber during heating. Fixed lengths of doped silica fiber are spliced to different lengths of undoped fiber and then evaporated by feeding into the focus of a CO2 laser. During evaporation, erbium ions are precipitated in the doped silica fiber to control the erbium concentration in the remaining SiO2, which is melted into a microsphere. By increasing the length of the undoped section, a critical point is reached where effectively no ions remain in the glass microsphere. The critical point is found using the spectra of the whispering gallery modes in microspheres with equal sizes. From the critical point, it is estimated that, for a given CO2 laser power, 6.36 x 10-21 mol of Er3+ is lost during the evaporation process for every cubic micron of silica fiber. This is equivalent to 1.74 x 10-7 mol of Er3+ lost per mol of SiO2 evaporated. This result facilitates the control of the doping concentration in WGLs and provides insight into the kinetics of laser-induced evaporation of doped silica.
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 156 of
  
  Title:Polarization-encoded 3D structured light and multifocal spot arrays generation based on metasurface
  
  Author(s):Zhao, Jiaqi; Ge, Suyang; Li, Yingbo; Liu, Zilei; Yang, Weihua; Li, Siqi
  Source: MODERN PHYSICS LETTERS B  Volume: 38  Issue: 23  DOI: 10.1142/S0217984924501860  Published: 2024  
  Abstract:Fluorescence microscopy possesses the advantages of high resolution, high sensitivity, molecular specificity and noninvasiveness, providing an important tool in life science research. The multifocal array and 3D structured light are two kinds of important light fields that are often used in scanning fluorescence microscopy systems and wide-field fluorescence microscopy systems. However, traditional methods for generating multifocal arrays and 3D structured light illumination rely on various bulk optical components, making it challenging to achieve compact optical systems. Besides, generating these two types of illumination typically requires two separate and independent optical systems, hindering the integration of different types of fluorescence microscopy systems. Here, a dielectric metasurface is proposed that can achieve the switching between multifocal arrays and 3D structured light through polarization state modulation, greatly simplifying the illumination optics of fluorescence microscopy systems and facilitating the integration of different types of fluorescence microscopy systems.
  Accession Number:
  ISSN: 0217-9849
  eISSN: 1793-6640