2024

• Record 277 of
  
  Title:Adaptive Kalman Filter Based on Online ARW Estimation for Compensating Low-Frequency Error of MHD ARS
  
  Author Full Names:Su, Yunhao(1,2); Han, Junfeng(1); Ma, Caiwen(1); Wu, Jianming(3); Wang, Xuan(1); Zhu, Qinghua(3); Shen, Jie(3)

  Source Title:IEEE Transactions on Instrumentation and Measurement

  Language:English

  Document Type:Journal article (JA)

  Abstract:Magnetohydrodynamic angular rate sensor (MHD ARS) can precisely detect angular vibration information with a bandwidth of up to one kilohertz. However, due to secondary flow and viscous force, it experiences performance degradation when measuring low-frequency angular vibrations. This article presents an adaptive Kalman filter that uses online angular random walk (ARW) estimation to correct for the low-frequency error of MHD ARS, where a microelectromechanical system (MEMS) gyroscope is used to measure low-frequency vibrations. The proposed algorithm determines the signal frequency based on the ARW coefficients and adjusts the measurement noise covariance to achieve accurate fusion results. Thus, the method solves the problem of frequency-dependent variation of the amplitude response of the sensors in data fusion. Initially, the algorithm calculates the ARW coefficient recursively utilizing the measurement signals of both sensors. Then, the operational frequencies of both sensors are determined by analyzing the correlation between the ARW coefficient and frequency. Subsequently, in the Sage-Husa adaptive Kalman filter (SHAKF), the Kalman gain matrix is adjusted by modifying the measurement noise variances of both sensor signals individually. Moreover, the stability of the proposed algorithm is achieved by introducing an adaptive matrix to constrain the measurement noise covariance estimation. In the experiment, the fusion effects of single-frequency and mixed-frequency signals are tested separately. The experimental results show that for frequency variation and frequency mixing, the proposed algorithm in this study significantly improves the fusion results. © 1963-2012 IEEE.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, The Photoelectric Tracking and Measurement Technology Laboratory, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) China Aerospace Science and Technology (CASC), Shanghai Academy of Spaceflight Technology, Shanghai; 200240, China

  Publication Year:2024

  Volume:73

  Start Page:1-10

  Article Number:9509510

  DOI Link:10.1109/TIM.2024.3375962

  数据库ID（收录号）:20241515880340
• Record 278 of
  
  Title:Study on the Flexible Support Structure of the Linear Moving Mirror of the Spaceborne Michelson Interferometer
  
  Author Full Names:Yang, Shuai(1,2); Sun, Jian(1); Yan, Qiangqiang(1); Y., Feng; F., Tian; X., Hao; C., Chang; J., Zhu; L., Wang; S., Yao

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:The support structure of the moving mirror constitutes the most crucial component of the high-precision Michelson interferometer，exerting a decisive impact on the quality of the interference signal. Conventional moving mirror support is accomplished through mechanical guide rails or magnetic levitation in combination with a drive motor，which is expensive，difficult to maintain，has a low life span，and has low guiding accuracy under the load of large mass and large stroke angle mirrors. To address these issues，a flexible support structure for the moving mirror of the Michelson interferometer is designed，featuring low cost，high precision，large load capacity，and large travel range. In this paper，the working principle of the Michelson interferometer is presented，and the impacts of the travel of the moving mirror，guiding accuracy，and velocity uniformity on the accuracy and stability of the interferometer are analyzed. The influence of the parasitic displacement perpendicular to the direction of motion on the parasitic path difference is quantified when the angle mirror is employed as the moving mirror. With the parallelogram guiding structure serving as the basic prototype，four parallelogram structures are nested both internally and externally to form the fundamental framework of the support structure，effectively amplifying the motion stroke of the entire structure. The flexible support structure is arranged symmetrically to counteract the parasitic displacement in the horizontal direction. Taking the load capacity，travel，and guiding accuracy of the flexible support structure as the optimization targets，the structural stiffness model is proposed. Based on the Awtar beam constraint model，the force-displacement relationship of the flexible reed with unilateral constraint is derived from the deformation mechanism of the cantilever beam，and subsequently，the stiffness formula of the flexible reed with unilateral constraint is deduced. The stiffness model of two unilateral constrained flexible reeds is obtained by means of Hooke's law. On this basis，the stiffness model of the entire flexible structure is derived in accordance with the series-parallel relationship of the flexible reeds in the flexible support structure. The finite element method combined with the stiffness model of the flexible structure is utilized to optimize the size parameters of the structure，and the transition fillet is set at the connection of the flexible reed and the rigid part to mitigate the stress concentration phenomenon. By comparing the ratios of yield strength to elastic modulus of different materials，7075 aluminum alloy is determined as the optimal material for the structure， and the three-dimensional model design and simulation of the flexible structure are conducted. The finite element analysis results indicate that the maximum tensile stress of the flexible structure amounts to 169 MPa，the structural safety margin is 1.98，and the parasitic displacement perpendicular to the movement direction is less than 4.1 μm when the travel attains 4.5 mm under the load of 1.5 kg（angle mirror）. A special test platform was established by means of a spiral micrometer，a high-precision grating scale meter，a digital dynamometer，and weights. The force-displacement relationship and parasitic displacement of the test pieces were examined，and the errors between the simulation results and the experimental results were analyzed. The results demonstrate that the parasitic displacement perpendicular to the motion direction is less than 3.2 μm and 4.7 μm，and the root-mean-square error of straightness is 0.96 μm and 1.5 μm respectively when the flexible support structure is subjected to 0.5 kg and 1.5 kg load（angle mirror）within the range of 4.5 mm travel. The test results of this structure are consistent with the design results，and can meet the support requirements of the satellite-borne Michelson interferometer for high-precision linear moving mirrors. It can also be used in other motion systems that require large stroke，large load，long life，and high guiding accuracy. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) DFH Satellite Co.，Ltd, Beijing; 100094, China; (4) Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun; 130033, China

  Publication Year:2024

  Volume:53

  Issue:10

  Article Number:1022002

  DOI Link:10.3788/gzxb20245310.1022002

  数据库ID（收录号）:20244717395144
• Record 279 of
  
  Title:On-line measurement of COD and nitrate in water against stochastic background interference based on ultraviolet–visible spectroscopy and physics-informed multi-task learning
  
  Author Full Names:Liu, Jiacheng(1,2,3); Yu, Tao(1); Wang, Xueji(1); Liu, Xiao(1); Wu, Lichao(4); Liu, Hong(1); Zhao, Yubo(1,2); Zhou, Guangya(3); Yu, Weixing(1); Hu, Bingliang(1)

  Source Title:Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

  Language:English

  Document Type:Journal article (JA)

  Abstract:Traditional ultraviolet–visible spectroscopic quantitative analytical methods face challenges in simultaneous and long-term accurate measurement of chemical oxygen demand (COD) and nitrate due to spectral overlap and the interference from stochastic background caused by turbidity and chromaticity in water. Addressing these limitations, a compact dual optical path spectrum detection sensor is introduced, and a novel ultraviolet–visible spectroscopic quantitative analysis model based on physics-informed multi-task learning (PI-MTL) is designed. Incorporating a physics-informed block, the PI-MTL model integrates pre-existing physical knowledge for enhanced feature extraction specific to each task. A multi-task loss wrapper strategy is also employed, facilitating comprehensive loss evaluation and adaptation to stochastic backgrounds. This novel approach significantly outperforms conventional models in COD and nitrate measurement under stochastic background interference, achieving impressive prediction R2 values of 0.941 for COD and 0.9575 for nitrate, while reducing root mean squared error (RMSE) by 60.89 % for COD and 77.3 % for nitrate in comparison to the conventional chemometric model partial least squares regression (PLSR), and by 30.59 % and 65.96 %, respectively, in comparison to a benchmark convolutional neural network (CNN) model. The promising results emphasize its potential as a spectroscopic instrument designed for online multi-parameter water quality monitoring against stochastic background interference, enabling long-term accurate measurement of COD and nitrate levels. © 2024

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Department of Mechanical Engineering, National University of Singapore, 117575, Singapore; (4) Radboud University, Nijmegen; 6525XZ, Netherlands

  Publication Year:2024

  Volume:323

  Article Number:124857

  DOI Link:10.1016/j.saa.2024.124857

  数据库ID（收录号）:20243016765881
• Record 280 of
  
  Title:A Novel Turbidity Compensation Method for Fluorescence Spectroscopy and Application in the Detection of Two Algae Species
  
  Author Full Names:Li, Ruizhuo(1,2); Dong, Jing(1,2); Wu, Guojun(1,3); Gao, Limin(1); Yang, Min(4)

  Source Title:SSRN

  Language:English

  Document Type:Preprint (PP)

  Abstract:Turbidity interference in measurements can reduce the accuracy of fluorescence detection. Conventional turbidity compensation methods directly establish the relationship between turbidity value and fluorescence but cannot accurately characterize the complex interference of turbidity on fluorescence detection. This paper introduces a novel turbidity compensation technique that separates the interference caused by turbidity particles into scattering enhancement and scattering-absorption attenuation components and corrects them separately. First, the scattering spectrum overlapping with fluorescence is estimated and subtracted from the actual sample spectrum to mitigate the fluorescence enhancement caused by scattering. Then, attenuation coefficients at different turbidity intervals are calculated to compensate for fluorescence attenuation. Finally, the two components are combined to obtain the final corrected result. Based on the proposed method, the fluorescence spectra data of Platymonas helgolandica var. tsingtaoensis and Synechococcus elongatus under different turbidity interferences were analyzed. Enhancement and attenuation coefficients based on turbidity values and scattering spectra were determined, ensuring adaptability to known and unknown turbidity conditions. The study results show that the fluorescence variation at different concentrations and turbidity levels are influenced by sample concentration and turbidity, exhibiting nonlinear behavior. The compensation model developed was applied to experimental data, achieving a mean relative error of less than 4% and a satisfactory root-mean-square error, significantly enhancing prediction accuracy. This method offers a straightforward and rapid application to detect a wide range of fluorescent substances. © 2024, The Authors. All rights reserved.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Science, Xi'An; 710119, China; (2) College of Photoelectricity, University of Chinese Academy of Science, Beijing; 100049, China; (3) Laoshan Laboratory, Qingdao; 266237, China; (4) North China Sea Marine Technical Center, Ministry of Natural Resources Qingdao, 266033, China

  Publication Year:2024

  DOI Link:10.2139/ssrn.4903055

  数据库ID（收录号）:20240304540
• Record 281 of
  
  Title:Static and structural dynamic analysis of thick panel kirigami deployable structures
  
  Author Full Names:Li, Junlan(1,2); Wang, Cheng(3); Yan, Yucheng(1,2); Wang, Peng(1,2); Zhao, Jieliang(4); Zhang, Dawei(1,2)

  Source Title:Aerospace Science and Technology

  Language:English

  Document Type:Journal article (JA)

  Abstract:Thick panel origami and kirigami concepts have been wildly used to design novel deployable structures in various engineering applications. However, these novel folding methods usually involve complex connected topologies, which may lead to unclear and intricate characterized relationships between system properties and structural parameters, e.g., the position of cutting creases, design parameters and hinge stiffness arrangement, etc. In this paper, we propose theoretical models to describe the static and dynamic properties of thick panel kirigami structure in the fully deployed configuration. Firstly, the connected topology of the origami and kirigami structure is analysed, and the internal coupling topology of the structure is obtained. Based on the compliant matrix method, the static model of the structure is presented, and the different crease cutting modes of origami and kirigami arrays are discussed. Then, the motion modes of slight oscillation of structure are discussed and the structural dynamic model is obtained based on the Lagrange equation and validated by simulation. On this basis, the sensitivity analysis of the parameters is carried out, and the optimization model is given based on the comprehensive performance evaluation function. A physical prototype is optimized and tested, which indicates that our model is valid. This paper provides models for the structural static and dynamic properties of thick panel kirigami structures with complex connected topology, and the findings have a potential to be developed in other thick panel structures with origami and kirigami folding concepts. © 2024

  Affiliations:(1) Key Laboratory of Mechanism and Equipment Design of Ministry of Education, Tianjin University, Tianjin; 300072, China; (2) School of Mechanical Engineering, Tianjin University, Tianjin; 300072, China; (3) Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an; 710119, China; (4) School of Mechanical Engineering, Beijing Institute of Technology, Beijing; 100081, China

  Publication Year:2024

  Volume:155

  Article Number:109753

  DOI Link:10.1016/j.ast.2024.109753

  数据库ID（收录号）:20244817424131
• Record 282 of
  
  Title:Laser-guided anisotropic etching for precision machining of micro-engineered glass components
  
  Author Full Names:Li, Jun(1); Zhong, Shuai(1); Huang, Jiaxu(1); Qiu, Pei(1); Wang, Pu(1,2); Li, Hui(1); Qin, Chu(3); Miao, Duo(1); Xu, Shaolin(1)

  Source Title:International Journal of Machine Tools and Manufacture

  Language:English

  Document Type:Journal article (JA)

  Abstract:Micro-engineered glass components play a vital role in various domains, but their full potential remains untapped due to the lack of easily accessible high-precision machining methods for customizable microstructure. Our discovery of a new phenomenon, where laser-modified regions break the rule of inherently isotropic glass etching and regulate a directional anisotropic etching along modified tracks, has led to the development of a laser-guided anisotropic etching (LGAE) method. This method enables crafting precision glass microstructures with sharp features, smooth surfaces, and adjustable shapes and sizes. An ultrafast Bessel beam is utilized to create high aspect-ratio line-shaped modification within the glass. With a higher etching rate than pristine glass, the modified line guides directional anisotropic etching along the modified track, facilitating the formation of a V-shape with an angle altered by the etching ratio. These modified lines can further serve as basic building blocks to interconnect to construct a 3D internal modification region and then guide the glass's overall surface morphology etching evolution, enabling the creation of microstructures featuring designable shapes and adjustable feature sizes. To accurately predict and control the shape of the microstructures, we establish a finite difference etching model that incorporates localized etching rate regulation, validating the robustness and controllability of LGAE. This scalable method has successfully fabricated a 50 μm period micro-pyramid array with high uniformity over a centimeter-scale area, demonstrating its suitability for large-scale manufacturing. The showcased micro-engineered glass components encompass V-groove arrays for fiber alignment, blazed gratings for light modulation, and microchannels with customized trajectories for microfluidic chips. These advancements driven by LGAE can significantly contribute to the progress of glass-based research and industries. © 2024 Elsevier Ltd

  Affiliations:(1) Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen; 518055, China; (2) The Advanced Optical Instrument Research Department, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (3) School of Microelectronics, Southern University of Science and Technology, Shenzhen; 518055, China

  Publication Year:2024

  Volume:198

  Article Number:104152

  DOI Link:10.1016/j.ijmachtools.2024.104152

  数据库ID（收录号）:20241515905919
• Record 283 of
  
  Title:Performance improvement of a discrete dynode electron multiplication system through the optimization of secondary electron emitter and the adoption of double-grid dynode structure
  
  Author Full Names:Liu, Biye(1,2); Li, Jie(1); Chen, Song(3); Yang, Jishi(1); Hu, Wenbo(1); Tian, Jinshou(4); Wu, Shengli(1)

  Source Title:Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

  Language:English

  Document Type:Journal article (JA)

  Abstract:The discrete dynode electron multiplication system (DD-EMS) is the core part of commonly used photomultiplier tubes and electron multipliers, and it has a great influence on the signal amplification capability of these devices. In this work, the sputtering time of Mg target during the deposition of the surface MgO layer of the MgO/(MgO–Au)/Au multilayer film as the secondary electron emitter was optimized, and the strategy of double-grid structures applied at the 7th and 8th dynodes was proposed with the intention of improving the gain and stability of nine-stage DD-EMS under electron bombardment to satisfy the requirements of detecting the single photon or single charged particle. The investigation results show that the DD-EMS fabricated by using the MgO/(MgO–Au)/Au film with a Mg target's sputtering time of 3600 s has the highest maximal gain of 1.22 × 106 and the lowest gain attenuation rate of 15.7%/mC under electron bombardment. In addition, the DD-EMS with the double-grid structure has a higher maximal gain of 1.62 × 106 and a lower gain attenuation rate of 11.6%/mC under continuous electron bombardment, which are 32.8% increased and 17.7% reduced respectively in comparison with that of the single-grid structure. © 2024 Elsevier B.V.

  Affiliations:(1) Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic Science and Engineering, Xi'an Jiaotong University, Xi'an; 710049, China; (2) Beijing Orient Institute of Measurement and Test, Beijing; 100086, China; (3) China Telecom Corporation Limited Beijing Research Institute, Beijing; 102209, China; (4) Key Laboratory of Ultra-fast Photoelectric Diagnostics Technology, Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences, Xi'an; 710119, China

  Publication Year:2024

  Volume:1062

  Article Number:169162

  DOI Link:10.1016/j.nima.2024.169162

  数据库ID（收录号）:20240815578823
• Record 284 of
  
  Title:Lightweight and optimized U-frame design for space-borne two-dimensional turntable
  
  Author Full Names:Wei, Yu-Xuan(1,2,3); Wang, Zhen-Yu(1,3); Li, Zhi-Guo(1,3); Huang, Le-Hong(1,2,3); Yang, Kai(1,2); Ma, Yu-Bao(1,2)

  Source Title:Chinese Optics

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:Space-borne two-dimensional turntables are the main bearing mechanism of space cameras and other optoelectronic equipment, and the U-frame is the key supporting part of these turntables. In order to optimize the structure and lightweight design of the U-frame of the two-dimensional turntable and to develop a lightweight two-dimensional turntable with a high load-bearing ratio, we design a U-frame for the space two-dimensional turntable based on Carbon Fiber Reinforce Plastics (CFRP). First, a variable cross-section tubular structure U-frame was designed using carbon fiber composites instead of titanium alloy material considering the manufacturability. Then, according to the finite element modeling method based on the lay-up process, the carbon fiber U-frame was subjected to finite element modeling and simulation analysis. Then, a prototype U-frame was fabricated, and modal tests verified the accuracy of the finite element model. Finally, a three-level optimization method combining theoretical analysis, genetic algorithm, and the finite element method was proposed to optimize the design of carbon fiber U-frame ply angle, ply thickness, and ply sequence. The results indicate that the vibration patterns of the U-frame obtained from the modal test and simulation are identical and that the frequency difference is less than 5%. The initial design of the carbon fiber U-frame is 45.7% lighter than the titanium U-frame. Through the secondary optimization of the composite layup, the U-frame is further reduced in weight by 13.8%. Additionally, the intrinsic frequency of the U-frame is improved by 10.14%. It can be concluded that the composite modeling and optimization methods used in this paper are correct, and the designed carbon fiber U-frame meets the lightweight design requirements of space-born two-dimensional turntable. © 2024 Editorial Office of Chinese Optics. All rights reserved.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Key Laboratory of Space Precision Measurement Technology, Chinese Academy of Sciences, Xi’an; 710119, China

  Publication Year:2024

  Volume:17

  Issue:4

  Start Page:896-908

  DOI Link:10.37188/CO.2023-0227

  数据库ID（收录号）:20243116787564
• Record 285 of
  
  Title:Analysis and simulation of the effect of large optical range difference of common path coherent-dispersion spectrometer on the detection of exoplanet radial velocities
  
  Author Full Names:Guan, Shouxin(1,2); Liu, Bin(1,2); Chen, Shasha(1); Wu, Yinhua(3); Wang, Feicheng(1,2); Wang, Shaofei(6); Liu, Xuebin(1); Wei, Ruyi(4,5,6)

  Source Title:Optics Communications

  Language:English

  Document Type:Journal article (JA)

  Abstract:The Exoplanet Explorer common-path coherent-dispersion spectrometer (CODES) utilizes a unique combination of an asymmetric common path Sagnac interferometer and a low to medium resolution spectrometer. The ideal optical range difference (OPD) interval for CODES is OPD ∈ {15.06 mm, 19.45 mm}; however, the OPD of CODES is 64.3 mm to achieve better detection accuracy. Though they will increase the accuracy of detection, large OPDs outside of the ideal interval will also reduce the contrast of the interference fringes, making phase changes more hazy. This may also significantly affect the radial velocity inversion and reduce CODES's instrumental accuracy. This study creates an inverse tone mapping operator based on the photographic model and designs an inverse tone mapping algorithm called CODESCE. The outcomes of the experiments demonstrate that the tone mapping algorithm CODESCE in this work is appropriate for enhancing the contrast of interference fringe images with high OPD, and it can enhance the contrast of interference fringes by three orders of magnitude when OPD = 64.3 mm; the processed interference fringes are located in the range of interference fringe curves of the optimal OPD. By comparison with other current approaches, the suggested algorithm yields superior processing outcomes. © 2024

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology CAS, Xi'an Institute of Optics and Precision Mechanic of Chinese Academy of Sciences, University of Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) School of Optoelectronics Engineering, Xi'an Technological University, Xi'an; 710021, China; (4) Hubei Luojia Laboratory, Wuhan; 430072, China; (5) Wuhan Institue of Quantum Technology, Wuhan; 430072, China; (6) School of Electronic Information, Wuhan University, Wuhan; 430072, China

  Publication Year:2024

  Volume:561

  Article Number:130443

  DOI Link:10.1016/j.optcom.2024.130443

  数据库ID（收录号）:20241415840369
• Record 286 of
  
  Title:Analysis of InGaAs/InP Single Photon Avalanche Diodes With Multiplication Width in Sub-Micron
  
  Author Full Names:Qiao, Kai(1,2,3); Chang, Yu(1); Xu, Zefang(1,3); Yin, Fei(1); Liu, Liyu(1,3); Wang, Jieying(1); Su, Chang(1,3); Xu, Linmeng(1,3); Fang, Mengyan(1,3); Liu, Chunliang(2); Tian, Jinshou(1); Wang, Xing(1)

  Source Title:IEEE Journal of Quantum Electronics

  Language:English

  Document Type:Journal article (JA)

  Abstract:InGaAs/InP single-photon avalanche photodiodes (SPADs) is capable of detecting single-photon in the near-infrared spectrum for applications such as quantum communication, fluorescence lifetime imaging, and Light detection and ranging(LIDAR). The effect of multiplication layer width on the performance of SPADs in both linear and Geiger mode have been theoretically studied. Three-types of InGaAs/InP planer SPADs with different multiplication width are fabricated and evaluated. The results of this study suggest that modifying the width of the multiplication layer can regulate the breakdown voltage, punch-through voltage, and dark current of the device. It is found that the measured time jitter is decreasing with the reduction of the width of the multiplication region. These characteristics can be used to optimize the temporal resolution of SPADs device. © 1965-2012 IEEE.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences (CAS), Key Laboratory of Ultra-Fast Photoelectric Diagnostics Technology, Shaanxi, Xi'an; 710119, China; (2) Xi'an Jiaotong University, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronic Science and Engineering, Xi'an; 710049, China; (3) University of Chinese Academy of Sciences, Center of Materials Science and Optoelectronics Engineering, Beijing; 100049, China

  Publication Year:2024

  Volume:60

  Issue:4

  Start Page:1-7

  Article Number:4500107

  DOI Link:10.1109/JQE.2024.3399176

  数据库ID（收录号）:20242016094811
• Record 287 of
  
  Title:Multi-Grained and Confidence-Aware Multiple Instance Network for Infrared Target Detection
  
  Author Full Names:Chen, Weining(1,2,3); Yang, Hongtao(2); Chang, Sansan(2,3); Chen, Yunzhi(4); Wang, Xinlin(5); Chen, Yaohong(2,3)

  Source Title:IEEE Transactions on Geoscience and Remote Sensing

  Language:English

  Document Type:Journal article (JA)

  Abstract:Weakly supervised object detection (WSOD) methods that trains an object detection network using image-level labels has attracted much attention due to its cost-effective annotation and broad applied requirement. However, applying such weak label to detect targets in infrared images is not trivial due to the less discriminative target information and interference of complex backgrounds. This article proposes a multi-grained and confidence-aware multiple instance network (MCMIN) to detect infrared targets given the imprecise labels. The multiscale multi-grained feature extraction module is designed to capture discriminative features from different receptive fields for dim-small targets. The hierarchical multiple instance target detection module first applies L1-sparsity regularization to encourage the model generate reliable pseudo ground truth (GT), and then leverages the confidence-aware instance adaptive weighting strategy to refine proposals with particular emphasis, achieving more accurate target detection. The experimental results on two infrared target detection datasets illustrate that the proposed MCMIN outperforms other state-of-the-art WSOD methods with higher average precision (AP). The proposed approach decreases the false alarms. © 1980-2012 IEEE.

  Affiliations:(1) Northwestern Polytechnical University, School of Automation, Xi'an; 710129, China; (2) Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (3) Key Laboratory of Spacecraft Optical Imaging and Measurement Technology, Xi'an; 710119, China; (4) Hangzhou Vocational and Technical College, School of Electronic Information Engineering, Hangzhou; 310018, China; (5) Xidian University, Key Laboratory of Intelligent Perception and Image Understanding, Ministry of Education, School of Artificial Intelligence, Xi'an; 710071, China

  Publication Year:2024

  Volume:62

  Article Number:5005113

  DOI Link:10.1109/TGRS.2024.3422924

  数据库ID（收录号）:20242816673755
• Record 288 of
  
  Title:Analysis of Imaging Limit Capability for Natural Rendezvous of Low Earth Orbit Debris
  
  Author Full Names:Li, Yaru(1,2,3); Zhou, Liang(1,3); Liu, Zhaohui(1,3); She, Wenji(1,3); Cui, Kai(1,2,3)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:In order to achieve precise attitude monitoring of large-sized space debris，the spatial resolution of cameras is continuously improving. However，this improvement leads to an increasing blurring effect caused by relative motion during exposure time. It is particularly important to research on how to balance camera resolution and the issue of image blur caused by motion-induced displacement. For low earth orbit natural rendezvous imaging scenarios，changes in the camera's observational angle before and after the rendezvous lead to variations in the position and orientation of the target in the camera line of sight. The image motion generated as a result of this is referred to as intrinsic image motion in the natural rendezvous imaging scenario. This passage establishes the equation for the image plane position through the mapping relationship between the points of space target objects and their corresponding image points. The equation involves the transformation of coordinates in seven different coordinate systems. In theory，taking the derivative of this equation with respect to time yields the instantaneous velocity equation for image motion. However，due to the immense computational complexity of the matrix and numerous parameters involved （including the orbital parameters of the imaging platform and target，spatial resolution of the camera，exposure time，etc.），it is impractical to provide an exact expression for intrinsic image motion. Therefore，we obtain the image plane positions at different time points based on specific orbital and imaging parameters，calculate the intrinsic image motion within the exposure time，and then employ a data fitting method to obtain a model for the intrinsic image motion function. Through analyzing the relative radial velocity of the target with the camera and the displacement of the target along the optical axis at the rendezvous moment，it can be understood that the rotational image motion of the target around the optical axis is a primary factor in intrinsic image motion. Therefore，this intrinsic image motion is directly correlated with the relative rotational angular velocity between the target and the camera，exposure time，angular separation between the target and the camera，and the spatial resolution of the camera. Taking into consideration these influencing factors，this paper calculates the intrinsic image motion for specific imaging orbits and various influencing factors using the image plane position equation. The obtained data is utilized as a training set for fitting the intrinsic image motion function. The fitting correlation coefficient for the training set is 0.99，with a root mean square error of 0.12. Subsequently，intrinsic image motion calculated with different orbital parameters is used as a test set to validate the accuracy of the fitting function. The correlation coefficients for different independent variables are all greater than 0.9，and the root mean square error are all less than 0.2. This indicates that the fitting accuracy of the intrinsic image motion function is high，and the fitting results are reliable. The intrinsic image motion function model reveals that intrinsic image motion is linearly correlated with relative rotational angular velocity，exposure time，and the angular separation between the target and the camera. It is also exponentially correlated with the spatial resolution of the camera. This paper analyzes the impact of this image motion on the modulation transfer function. When the image motion is greater than 0.5 pixels， the modulation transfer function decreases by approximately 10%，failing to meet the overall system design requirements. Therefore，this paper takes an image displacement of 0.5 pixels as the maximum allowable displacement and establishes a constraint on the camera's spatial resolution at the time of natural intersection. This constraint illustrates the relationship between camera resolution and the relative angular velocity，exposure time，and angular separation between the target and the camera under the condition of satisfying the maximum allowable image motion. Taking a specific set of imaging orbits as an example，we demonstrate the method of calculating the maximum resolution of the camera at the rendezvous moment using this constraint condition. We point out that in low earth orbit rendezvous imaging scenarios，even if the spatial camera resolution exceeds this limit，there is no improvement in image quality. This indicates that the constraint condition has a significance for the design of imaging cameras and the selection of exposure parameters. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Xi′an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Key Laboratory of Space Precision Measurement Technology, Chinese Academy of Sciences, Xi'an; 710119, China

  Publication Year:2024

  Volume:53

  Issue:8

  Article Number:0811003

  DOI Link:10.3788/gzxb20245308.0811003

  数据库ID（收录号）:20243917106310