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Record 289 of
Title:Construction of the optical-mechanical installation and calibration process technology on the basis of the digital twin
Author(s):Chou, Xiao-Quan(1); Li, Xiao-Yan(1); Kang, Shi-Fa(1); Yang, Fan(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12507 Issue: null Article Number: 125070Z DOI: 10.1117/12.2655281 Published: 2023
Abstract:With the continuous development of the technology and informatization, the current research and application of the technology of the digital twin has become a hot spot. The technology of the digital twin is applied to the optical-mechanical system design, the optical-mechanical manufacturing, the optical-mechanical installation and calibration, as well as the inspection over the whole process and the whole life cycle. The objective of this paper is to study the construction of the digital twin in the crucial links of the installation and calibration process over the whole process of the optical-mechanical system, as well as the modeling and simulation of the digital twin in the optical-mechanical installation and calibration process, including the ideal model simulation, the optical-mechanical part-level simulation, the optical-mechanical thermal coupling simulation, the total integration simulation, as well as the prediction of the use effect of the optical-mechanical system. In the past, the ex post data were collected in order to feed back for the model design and the process, so as to improve the accuracy of the simulation. Accordingly, the actual measured data of the optical-mechanical part entity are substituted into the model. Moreover, the results of the simulation integration are used to correct the technical scheme of the process. Furthermore, the physical entity data generated during the execution of the correction scheme are transmitted to the simulation model once again, so as to achieve the dynamic data interactive application of the optical-mechanical system in the physical entity and the virtual model. Thus, the dynamic system is formed. In the end, the data exchange, sharing as well as the mutual mapping between the physical entity and the virtual entity during the installation and calibration of the optical-mechanical system can be realized. In conclusion, the provision of the real-time data, the analysis and optimization of the installation and calibration process, as well as the decision making of the implementation plan in the aspect of the installation and calibration application of the optical-mechanical system, which provide an effective way for the process design of the installation and calibration of the optical-mechanical system as well as the digital improvement of the installation and calibration technology. ? 2023 SPIE.
Accession Number: 20230613537945
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Record 290 of
Title:Epicycle-model-guided arbitrary shaped customization of structured light
Author(s):Fan, H.H.(1); Tai, Y.P.(1,2); Li, H.H.(1); Li, X.Z.(1,2,3); Zhan, Q.W.(4)
Source: Applied Physics Letters Volume: 122 Issue: 23 Article Number: 231104 DOI: 10.1063/5.0147002 Published: June 5, 2023
Abstract:Structured light has been exploited as an important tool for particle manipulation along a desired complex path. However, generating the required structured light illumination for the creation of an arbitrary shape without an analytic expression as a guide is challenging, specifically for designing a structured beam by mapping the shape of an arbitrary object. To address this issue, we propose an effective scheme to customize structured light freely and precisely by modifying the epicycle model in astrophysics. Predesigned structured beams can be identified with or without explicit analytic expressions of the desired shapes. Moreover, we study the roles and relationships between the number of epicycles and the number of key points. The local stretching and transformation of a specific structured beam are also analyzed. The advantages of the proposed method are demonstrated by conducting dynamic manipulation experiments using polystyrene particles. This method is simple and intuitive and provides an effective toolkit for the design of structured light for more complex tasks, thus facilitating advanced applications in optical manipulations. ? 2023 Author(s).
Accession Number: 20232514253242
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Record 291 of
Title:Effect of residual chlorine on fluorescence emission of Dy3+ doped chalcogenide glasses with low gallium content
Author(s):Cui, Jian(1,2); Xu, Yantao(1); Xiao, Xusheng(1); Cui, Xiaoxia(1); Liu, Chengzhen(1); Guo, Haitao(1,2,3)
Source: Journal of the American Ceramic Society Volume: 106 Issue: 2 Article Number: null DOI: 10.1111/jace.18783 Published: February 2023
Abstract:Chlorine or chlorides are usually used as a dehydrating agent for removing the O-H or S(Se)-H in the preparation of high-purity chalcogenide glasses. However, the residual chlorine in some rare-earth ions doped chalcogenide glasses was found to have a great negative impact on fluorescence emission. In this work, the effect of residual chlorine on the fluorescence emission of Dy3+ ions in serial (Ge)GaAsSbS glasses was studied quantitatively, and the reasons were discussed. Cl2 gas and SbCl3 were used as the source of chlorine and their residual contents were controlled by the post-distillation process and added content, respectively. The results can give some suggestions for how to eliminate the negative effects of chlorine and improve the glass’ optical gain properties. ? 2022 The American Ceramic Society.
Accession Number: 20224112861394
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Record 292 of
Title:GLMF-Net: A Granular-level and Layer-level Multi-scale Fusion Network for Change Detection
Author(s):Li, Wenyao(1); He, Renjie(1); Dai, Yuchao(1); Zhang, Pengchang(2); He, Mingyi(1)
Source: Proceedings of the 18th IEEE Conference on Industrial Electronics and Applications, ICIEA 2023 Volume: null Issue: null Article Number: null DOI: 10.1109/ICIEA58696.2023.10241769 Published: 2023
Abstract:Change detection (CD) is a crucial task in remote sensing (RS) image analysis. In recent years, the development of deep learning has led to significant progress in this field. However, current deep learning-based methods struggle to achieve accurate change detection in complex scenes, often resulting in false detections and loss of details of change objects. In this paper, we propose a novel granular-level and layer-level multi-scale fusion network (GLMF-Net) to overcome these problems. The GLMF-Net consists of two key modules: the granular-level multi-scale fusion (GMF) module and the layer-level multi-scale fusion (LMF) module. The GMF module locates potential change objects by capturing granular-level change features, while the LMF module excavates the details of change objects in shallow features. To achieve inter-layer feature fusion, we also develop a group-wise guidance operation in the LMF module. Extensive experimental results demonstrate that our GLMF-Net significantly improves the accuracy of change detection in complex scenes, and achieves the state-of-the-art performance on the widely used CDD and LEVIR-CD datasets in terms of five standard metrics. ? 2023 IEEE.
Accession Number: 20234114875712
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Record 293 of
Title:Design of compact dual-core terahertz polarization beam splitter with broad bandwidth
Author(s):Zheng, Yunqiang(1); Liu, Jinqiu(2); Wang, Yufei(1); Liu, Huan(1); Wang, Wei(1); Xie, Xiaoping(1)
Source: Microwave and Optical Technology Letters Volume: 65 Issue: 5 Article Number: null DOI: 10.1002/mop.33384 Published: May 2023
Abstract:A novel dual-core structure based on cyclic olefin copolymer (COC) photonic crystal fiber (PCF) is proposed for realizing Terahertz (THz) polarization beam splitting. The dependence of coupling length and structural parameters of the THz polarization beam splitter (TPBS) is analyzed. The confinement loss, effective material loss, and extinction ratio (ER) are examined. The numerical simulation results show, two orthogonal polarization modes are separated completely within a device length of only 45.16 mm owing to the different coupling length in x- and y-polarization directions. The maximum polarization ER of 107.7 dB is obtained at 0.54 THz. The bandwidth with ER greater than 20 dB reaches 0.02 THz. The proposed compact dual-core TPBS will find extensive applications in THz photonic systems. ? 2022 Wiley Periodicals LLC.
Accession Number: 20222712304950
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Record 294 of
Title:The Key Research of High Speed Camera Based on Multiple Core CMOS Sensors
Author(s):Li, Yanzhang(1); Zeng, Hong(1); Liu, Guangsen(2); Zhu, Jun(1); Che, Xiaoling(1)
Source: Lecture Notes in Electrical Engineering Volume: 996 LNEE Issue: null Article Number: null DOI: 10.1007/978-981-19-9968-0_29 Published: 2023
Abstract:High speed camera is different from traditional remote sensing camera. Object details can be captured through high frame rate imaging. Due to the limited exposure time, the amount of data transmitted and other factors, a single camera cannot achieve the ultra-high frame rate imaging function, and multiple cameras are required to work together. The camera is mainly used for high-speed shooting of moving targets. High frame rate cameras are mainly foreigner design, and domestic cameras are still in their infancy. Especially in the design of a single camera to achieve high frame rate, it is limited by the performance of the CMOS sensor. This paper uses the design of interpolating multiple CMOS sensors into a high frame rate camera, which is not limited by the frame rate of a single CMOS sensor. It only needs the accurate interval exposure of each CMOS sensor, which needs to deal with the exposure synchronization of many CMOS sensors, otherwise the inter-polated high frame rate will be meaningless. ? 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Accession Number: 20231113734082
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Record 295 of
Title:Analytical method for calculating internal stray radiation from an IR spectrometer based on the view factor
Author(s):Zhang, Zhi-Nan(1,2); Li, Li-Bo(1); Hu, Bing-Liang(1); Wang, Peng-Chong(1); Yang, Ying(1); Ke, Shan-Liang(1); Wang, Shuang(1); Li, Si-Yuan(1)
Source: Applied Optics Volume: 62 Issue: 3 Article Number: null DOI: 10.1364/AO.478330 Published: January 20, 2023
Abstract:Optomechanical components such as the lens barrels and frames of IR spectrometers produce strong internal stray radiation, which reduces the instrument’s SNR and dynamic range. An IR internal stray radiation calculation method based on an analytical model of the view factor is proposed. The mathematical model of the view factor calculation method of typical optomechanical components is established. For any IR optical systems, the internal stray radiation can be quickly and accurately calculated by adjusting the coordinate systems in the calculation method. Based on the proposed method, the internal stray radiation of a double-pass long-wave IR spectrometer was calculated. The calculation results are consistent with the simulation results. The RMS value of the relative error between the calculated value and the simulated value is around 11%. To verify the proposed method, an experiment was conducted to test the internal stray radiation of the long-wave IR spectrometer. The internal stray radiation test results agree with the calculated and simulated results, and the relative error between the test results and the calculation results is within 9%. ? 2023 Optica Publishing Group.
Accession Number: 20230713580393
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Record 296 of
Title:Small sample learning of calligraphy and painting identification based on hyperspectral image
Author(s):Tang, Xingjia(1,2); Zhang, Pengchang(1); Xu, Zongben(2); Hu, Bingliang(1); Li, Siyuan(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12617 Issue: null Article Number: 126170Y DOI: 10.1117/12.2663778 Published: 2023
Abstract:The existence of forgeries has seriously affected the fair trading, protection and inheritance of calligraphy and painting, while, it been unable to identify high-level counterfeiting means by traditional expert eye identification method. Combining the advantages of material attribute recognition and imaging analysis of hyperspectral imaging technology with the powerful feature expression and classification ability of convolutional neural network, the identification level of calligraphy and painting could be improved. However, there are still some practical problems in the application, like the small sample learning problem caused by the difficulty in obtaining the real hyperspectral sample data of calligraphy and painting. In this paper, a 10-hidden layers 2D-CNN convolutional neural network transfer learning method for calligraphy and painting identification with data enhancement is proposed by using a large number of relevant picture data and a small amount of MNF dimensionality reduced hyperspectral data. The experimental test shows that on the test set of this paper, for the identification of calligraphy and painting authors and authenticity, the accuracy of migration learning with data enhancement under the original sample are separately 97.5% and 94.8%, the accuracy of migration learning with data enhancement under half of the original sample are separately 94.3% and 92.8%, which shows the migration learning and data enhancement is helpful, and the identification accuracy of half of the original sample basically reaches the identification accuracy of the original sample without data enhancement and transfer learning, whose accuracy are 92.1% and 92.5%. ? 2023 SPIE.
Accession Number: 20232114130605
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Record 297 of
Title:Two Step Phase-shifting Interferometry by Least Squares Iterative Optimization
Author(s):Liu, Chang(1); Du, Hubing(1); Feng, Leijie(1); Yan, Xingxu(1); Zhang, Gaopeng(2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 52 Issue: 2 Article Number: 0212003 DOI: 10.3788/gzxb20235202.0212003 Published: February 2023
Abstract:The temporal phase shifting technique is a powerful tool that is used in numerous industrial，research and development applications， such as range acquisition， industrial inspection， reverse engineering，and object recognition. However，the accuracy of temporal phase shifting technique is limited by the phase-shifting uncertainties resulting from the imperfect conditions in the real testing environments，such as the miscalibration. So，there is a strict requirement on the precision of the phase shifter. To remove this requirement，there have been reported works about phase reconstruction with only two frames. Two-shot phase reconstruction，i.e.，the recovery of a complex-valued signal from two intensity patterns that are nearly identical apart from a random and unknown phase shift between them，which can reconstruct the phase without local sign ambiguity using the minimum number of interferograms with higher measurement accuracy than the single-frame algorithm，is especially prevalent in imperfect testing conditions where requires reducing the detrimental effects on the measurements from mechanical vibrations，ambient air turbulence，and temperature changes. In the implementation of the technique，the filtering procedure of the fringe normalization，background removal，or noise reduction must be applied to the two arbitrarily phase shifted patterns before the phase demodulation. However，due to certain experimental imperfections of any physical system that are hard to model accurately，we cannot assume any particular behavior for the intensity pattern in a general case. In this case，the two-shot phase reconstruction technique may have an unsatisfactory filtering effect during the phase demodulation. Recently，much special attention is paid to the algorithm that does not require pre-filtering. In this work， we proposed a novel two-shot phase reconstruction method that can bypass the pre-filtering with the help of the least squares iterative phase shifting algorithm. In our method，a rough estimation of the phase shift is obtained by correlation operation of two background removed fringe patterns under the approximate orthogonal characteristic of a trigonometric function. Thus，we can compute the phase using two frame phase shifting algorithm. Then，using this initial phase shift estimation，both the phase shift and background light improved by solving other N linear equation systems in a frame-wise manner. Further，the two background removed fringe patterns are updated. Iterating this process，it eventually settles down in the searched phase. In essence，this method is a two-frame version of the AIA algorithm except for the use of background terms，which is usuallydiscarded in the standard AIA algorithm. To reduce the effect of spatially varying background intensity and modulation amplitude，we divide the captured interferogram space into several blocks（for example，150×150）. if the blocks are sufficiently small，we may consider that the background intensity and modulation amplitude in each block do not have pixel-to-pixel variation and can be assumed as constants. Then we select one block，and the necessary parameters are estimated by the phases and the intensity in this block. Our novel approach consists of the following steps：1）Estimate an initial phase step by s correlation operation of two background removed fringe patterns，2）Compute the measurement phase using the initial phase step，and 3）Use the obtained intermediate parameters for continually updating both the two filtered fringe patterns and the phase step until the accurate phase is reconstructed through the searched phase shift. To demonstrate，the proposed method is compared with other state-of-the-art two-frame random phase-shifting algorithms： CV and PCA&LSI， for they can accomplish the phase reconstruction universally and accurately. We choose the typical scenarios，namely open-fringe pattern，and closed-fringe pattern as our test case. Both simulations and measurement experiment results obtained using the proposed method indicate that it is a simple，albeit robust solution for phase extraction from two-frame unknown phase shift fringe pattern. ? 2023 Chinese Optical Society. All rights reserved.
Accession Number: 20231713946103
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Record 298 of
Title:LCVR-based Stokes polarimeter: Principles and evaluation
Author(s):Chang, Lingying(1); Wang, Guanru(1); Wang, Xinyou(1); Qiu, Yuehong(2); Chen, Kui(1); Liang, Chi(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12921 Issue: null Article Number: 129210E DOI: 10.1117/12.2687651 Published: 2023
Abstract:The polarimetric imaging system can acquire not only the target's two-dimensional light intensity distribution information but also the Stokes polarization vector information corresponding to the target light intensity distribution. The Stokes vector information can enhance the target's contrast, highlighting the target from the complex background information. The LCVR-based Stokes polarimeter uses a liquid crystal variable retardation (LCVR) instead of the rotating waveplate in conventional measurement techniques, which enables polarization measurements without moving parts. This paper first introduces the measurement principle of the Stokes vector method, the working principle of LCVR, and the parameters of commonly used evaluation indicators in polarimetric measurement systems. Then, a two-channel single LCVR-type polarimeter measurement scheme is proposed, which uses a split beam element (prism PBS, Savart plate, or Wollaston prism) and a single LCVR to obtain the full Stokes parameters of the target. Then the measurement matrix and light intensity calculation formulas for the polarimeter and polarization spectrometer were derived, and the evaluation parameters of the system (CN, RAD, EWV) were calculated. The study and evaluation analysis provide some theoretical references for studying the LCVR-based Stokes polarimeter. ? 2023 SPIE.
Accession Number: 20234815132540
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Record 299 of
Title:Error analysis of FLC polarization imager in full polarization state with wide spectrum
Author(s):Chang, Lingying(1); Chen, Kui(1); Liang, Chi(1); Qiu, Yuehong(2); Zhang, Youbiao(1); Li, Jiayi(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12963 Issue: null Article Number: 129630S DOI: 10.1117/12.3007446 Published: 2023
Abstract:The ferroelectric liquid crystal (FLC)-based wide spectrum polarization imager can quickly acquire the full polarization information of the target, however, the polarization elements error will affect the accuracy of the system polarization parameters (DOP, EOP, and AOP) measurement. In this paper, to investigate the influence of polarization element error on the acquisition of polarization information of the measured target, the influence of element parameter error on the measurement of target polarization parameters is analyzed. First, the working principle of FLC and the structural composition of the system of wide spectrum polarization imager based on FLC are introduced; second, the measurement matrix of the wide spectrum polarization imaging system is calculated based on the CCD spectral response curve, and the variation of the wave plate phase retardation with wavelength; then, the error model of the system for solving the full polarization parameters is established; finally, the effects of the parameter (azimuth angle F1θ, tuned rotation angle F1α, phase retardation F1δ of FLC2; azimuth angle Hθ, phase retardation Hδ of HWP; azimuth angle F2θ, tuned rotation angle F2α, phase retardation F2δ of FLC2; azimuth angle Qθ, phase retardation Qδ of QWP; azimuth angle Pθ of P) errors of each element of the polarization module on the DOP, EOP, and AOP measurements are analyzed. The simulation results show that: with the increase of the error of each element parameter of the polarization module, the measurement error of the polarization parameters are all increasing in different degrees; the error of F2α is the main factor affecting the measurement accuracy of the degree of polarization (DOP), the error of F1α is the main factor affecting the measurement accuracy of the ellipticity of polarization (EOP), and the error of F1θ is the main factor affecting the measurement accuracy of the angle of polarization(AOP); at [-2°,2°], the maximum measurement errors of DOP, EOP, and AOP are 2.83%, 6.98%, and 9.26%, respectively; when the errors of polarization element parameters are certain, the measurement errors will change with different polarization states of the target. The research method and results can provide research ideas and theoretical references for the error analysis research of the wide spectrum polarization imaging system based on FLC or other wide spectrum polarization imaging systems. ? 2023 SPIE. All rights reserved.
Accession Number: 20240215330718
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Record 300 of
Title:Optical axis consistency alignment method for 1m-diameter solar telescope
Author(s):Xing, Fu(1); Lei, Yu(1); Bindong, Ji(1); Keiwei, E.(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12976 Issue: null Article Number: 1297623 DOI: 10.1117/12.3009615 Published: 2023
Abstract:AISM telescope is the abbreviation of Accurate Infrared Magnetic System. This telescope is the first mid infrared system internationally used for observing the solar magnetic field. The system is an off-Axis telescope with an aperture of 1 meter. The optical path is complex and the light is folded over a long distance through multiple flat and aspheric mirrors and coupled with mechanical rotation axis. The conventional alignment methods cannot be applied. This paper describes the methods for reserving assembly reference for each module and the system optical axis consistency adjustment method. The method has been verified through actual experiment and can achieve high precision. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
Accession Number: 20240315401972
