2024

• Record 397 of
  
  Title:Sub-nanosecond Rising-edge Narrow Pulse Driver Circuit and Analog Simulation
  
  Author Full Names:Li, Yi(1,2); Wen, Wenlong(1); Wang, Qianhao(1); Li, Qianglong(1); Zhao, Hualong(1); Li, Feng(1)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:Semiconductor lasers have made great progress in theoretical research，practical application and technological development in the half century since their introduction. Today，they occupy the majority of the market share in the entire laser field，and are widely used in a variety of fields such as communication networks，medical aesthetics，laser sensing，and single-photon detection. Photon detection，for example，is a technique capable of detecting extremely low noise，with enhanced sensitivity enabling it to capture the smallest energy quantum of light，the photon. Not only does this technique allow for the precise counting of individual photons，which greatly enhances the accuracy and efficiency of detection，but it is also widely used in fields such as laser ranging and LIDAR to achieve high-resolution distance measurement and target detection. In laser ranging，the onset time of a laser pulse is usually defined by the rising edge of the pulse，so the steepness of the rising edge directly affects the accuracy of time-of-flight measurement. In LIDAR systems，a fast rising edge helps to shorten the laser emission time and increase the laser power，which in turn enhances the system's ability to sense the environment. Therefore，as the source of the laser signal，a semiconductor laser outputting narrow pulses with fast rising edges is crucial for improving the system accuracy. In this paper，a narrow pulse circuit with sub-nanosecond rising edge is designed，and the effects of inductance，capacitance and other parameters in the circuit on the rising edge of the output laser pulse are theoretically analyzed. The driver circuit uses a GaN integrated module with built-in driver as the main switch，and the semiconductor laser diode is driven by a reasonably designed driver circuit. At the same time，Field Programmable Gate Array（FPGA）is used as the control core to design the timing signals to realize the precise adjustment of the laser diode's pulse width and repetition frequency； and the thermoelectric cooler is driven by ADN8831 to realize the constant temperature control of the semiconductor laser. By simulating the circuit，it was found that the capacitor's ability to store and release energy increases with its value，allowing the circuit to release more charge per pulse，resulting in wider pulses and higher peak currents. Resistance only affects the peak current and an increase in resistance decreases the peak current. An increase in inductance extends the duration of the rising edge and reduces the peak current. Parasitic parameters in loop circuits，such as inductance，not only affect the speed of the pulse，but also affect the pulse waveform，making it more rounded or"dome"shaped. A relatively small capacitance has no significant effect on the overall performance. By reasonably designing the inductance and capacitance parameters and optimizing the circuit layout and wiring，sub-nanosecond rising edge laser narrow pulses can be achieved. The final experimental validation shows that the pulse front reaches 630 ps，the pulse width is adjustable from 5 ns to 15 ns，the repetition frequency is adjustable from 1 kHz to 10 kHz，the temperature of the LD is set from 25 ℃ to 26 ℃，and the RMS test value of the 12-hour power stability is 0.51%. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Photonic Manufacturing System and Application Research Center, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (2) School of Optoelectronics, University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:53

  Issue:10

  Article Number:1014002

  DOI Link:10.3788/gzxb20245310.1014002

  数据库ID（收录号）:20244717395111
• Record 398 of
  
  Title:A Centroiding algorithm for high precision cross strip anode readout of Photon Imaging Detector
  
  Author Full Names:Zuo, Xiaoyun(1,2); Zheng, Jinkun(1,2); Duan, Jinyao(1,2); Xu, Linmeng(1,2); Tuo, Hongli(1,2); Yang, Yang(1,2); Bai, Yonglin(1,2)

  Source Title:Proceedings of SPIE - The International Society for Optical Engineering

  Language:English

  Document Type:Conference article (CA)

  Conference Title:2024 Conference on Spectral Technology and Applications, CSTA 2024

  Conference Date:May 9, 2024 - May 11, 2024

  Conference Location:Dalian, China

  Conference Sponsor:Chinese Society for Optical Engineering

  Abstract:The cross strip (XS) anode detector is a photon counting imaging detector with high spatial resolution and good position resolution. This kind of detector is widely used in material science, medical imaging and environmental monitoring, especially in detecting weak photon signals. However, in order to fully tap the potential of the XS anode detector, advanced algorithms are needed to optimize the processing of image data. Centroiding algorithm, as one of the key factors affecting the imaging of detector, plays a vital role in improving the performance of detector. The traditional centroiding algorithm mainly relies on the peak value of charge distribution to locate the centroid, but it is easily disturbed by noise. In order to weaken the negative effect of noise, this paper designs a centroiding algorithm based on convolution, which selects data by setting threshold value and calculates the average value of all data larger than threshold value. In addition, considering that the input signal may introduce noise, the filtering operation is specially introduced. The experimental results demonstrate the superiority of the proposed method in calculating the centroid position. Compared with the traditional algorithm, the mean value interpolation convolution algorithm proposed in this paper improves the precision of solving the centroid coordinates and has good robustness. Specifically, the error range of the algorithm is obviously smaller than that of the traditional algorithm, and its error range is no more than 5%. This means that higher spatial resolution and faster counting rates can be expected without sacrificing too much accuracy. © 2024 SPIE.

  Affiliations:(1) Key Laboratory of Ultrafast Photoelectric Diagnostic Technology, Xi'an Institute of Optics and Precision Mechanics (XIOPM), Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences (UCAS), Beijing; 100049, China

  Publication Year:2024

  Volume:13283

  Article Number:132831P

  DOI Link:10.1117/12.3035681

  数据库ID（收录号）:20245217584406
• Record 399 of
  
  Title:Blue-green emitting ZnS0.75O0.25:Ce3+,x%Tb3+ phosphor with tunable fluorescence lifetime
  
  Author Full Names:Xing, Xue(1,2,3); Cao, Weiwei(1); Wu, Zhaoxin(2); Bai, Xiaohong(1); Gao, Jiarui(1); Liang, Xiaozhen(1); Wang, Bo(1); Wang, Chao(1); Shi, Dalian(1); Lv, Linwei(1); Bai, Yonglin(1)

  Source Title:Materials Letters

  Language:English

  Document Type:Journal article (JA)

  Abstract:A series of ZnS0.75O0.25:0.1%Ce3+,x%Tb3+ phosphors were prepared by high temperature solid state reaction method. These phosphors exhibited two mixed phases consisting of hexagonal phase ZnS and hexagonal phase ZnO with the average particle size of 13.83 μm and emitted blue-green light. The luminescence mechanism consisted of Zn vacancy defects, the 5d1 → 2F5/2 radiative transitions of Ce3+, the 5D4 → 7F5 and 5D4 → 7F6 radiative transition of Tb3+ induced by the energy transfer of Ce3+ → Tb3+. An equation for the variation of the fluorescence lifetime of ZnS0.75O0.25:0.1%Ce3+,x%Tb3+ phosphors with concentration of Tb3+ fraction was obtained by exponential fitting. The short fluorescence lifetime could be tuned within the range of 113 μs to 550 μs with the increase of Tb3+ concentration, and the color was tunable from blue to blue-green, which is of important application in the field of high-energy particle detection. © 2024 Elsevier B.V.

  Affiliations:(1) Key Laboratory for Space Science Low Light Level Detection Technology, Xi'an Institute of Optics & Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi'an; 710119, China; (2) School of Electronic Science and Engineering, Xi'an Jiaotong University, Shaanxi, Xi'an; 710049, China; (3) University of Chinese Academy of Sciences, Beijing; 100049, China

  Publication Year:2024

  Volume:372

  Article Number:137028

  DOI Link:10.1016/j.matlet.2024.137028

  数据库ID（收录号）:20243116772657
• Record 400 of
  
  Title:Detection Error Analysis and Control in Close-range Conditions of Solid-state Hybrid LiDAR
  
  Author Full Names:Ye, Meitu(1,2); Xie, Meilin(1,2,3); Guo, Min(1,2); Shi, Heng(1,2,3); Tian, Yan(1,2); Hao, Wei(1,2); Ding, Lu(1,2); Tian, Guangyuan(1,2)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:In recent years，hybrid solid-state LiDAR has gained widespread application across aerospace，autonomous driving，and UAV remote sensing due to its reasonable cost and advanced manufacturing technology. Despite its advantages in portability and long-range detection capabilities，many researchers overlook the inherent challenges such as systematic errors，random interference，and instability issues，particularly the"edge tailing"effect within the near-field range of tens of meters. This phenomenon significantly impairs the reliability of close-range detection and testing tasks. This article begins by outlining the fundamental 3D imaging principles of solid-state LiDAR and discusses the unpredictability of near-field detection errors. It introduces a method for analyzing a measured target's 3D point cloud data using the Oriented Bounding Box （OBB） algorithm，establishing a framework for subsequent data acquisition and analysis. Experimental statistical methods were then employed to quantitatively analyze the measurement results，elucidating the influence of systematic"edge tailing"on the direct fitting results of spheres. This study also identifies a variance in echo intensity between the tailing and central points. Leveraging the existing discovery，an automatic denoising method was devised to eliminate noise from the tailing point clouds，thereby reducing systematic errors. Moreover，the analysis reveals that measurement distance， target surface colour， and motion speed significantly contribute to random errors. Recommendations are made for optimizing working distance，target colour，and flight speed in near-field detection to minimize these errors and enhance measurement stability. A series of experiments were conducted to verify the effectiveness of these methods，measuring the attitude of a large angular velocity rotating target at a 30-meter range. Identification of"expansive"trailing points at the target edges，is enabling the establishment of a precise cutoff threshold for their filtering，meaning that optimal working distances enhance the accuracy of tracking and measuring cooperative targets，with white being the preferred target colour for both day and night conditions. The necessity of defining the dynamic speed limit of the target to select a LiDAR with an appropriate frame rate，minimizes significant accuracy losses. For laser LiDAR systems with a nominal accuracy of ±2 cm，the comprehensive error reduction methods proposed can maintain size measurements of rotating targets within ±3 cm at a 30 m near-field range. The conclusions of this study offer valuable guidelines for the application of hybrid solid-state LiDAR in the tracking and rendezvous of far-field and large targets. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, CAS, Xi'an; 710119, China; (2) Key Laboratory of Space Precision Measurement Technology, Chinese Academy of Sciences, Xi'an; 710119, China; (3) Pilot National Laboratory for Marine Science and Technology（Qingdao）, Qingdao; 266237, China

  Publication Year:2024

  Volume:53

  Issue:12

  Article Number:1212001

  DOI Link:10.3788/gzxb20245312.1212001

  数据库ID（收录号）:20250317701006
• Record 401 of
  
  Title:Nonmeasurable Range Elimination of Dispersive Interferometry
  
  Author Full Names:Huang, Jingsheng(1,5); Du, Wei(1); Wang, Jindong(1,2); Wang, Weiqiang(3); Wang, Yang(2); Li, Duidui(1); Chu, Sai T.(4); Zhang, Wenfu(2); Zhu, Tao(1)

  Source Title:ACS Photonics

  Language:English

  Document Type:Journal article (JA)

  Abstract:Dispersive interferometry (DPI) stands as a formidable method in both scientific and industrial realms, offering the capability for numerous measurement scenarios with remarkable accuracy over extensive ranges. The advent of on-chip soliton microcombs (SMCs) boasting a high repetition rate illuminates a promising pathway toward measurements free from dead zones. However, its application scenarios are considerably constrained by the nonmeasurable range (NMR)─the region proximate to the measurement period’s extreme points, which is circumscribed by the fast Fourier transform (FFT) steps and symmetry of the data calculation procedure. Here, we introduce an NMR elimination method that refines the DPI structure by engendering an asymmetric interference spectrum. Furthermore, a phase saltation tracking (PST) method for demodulating is devised, enabling measurements without NMR. Both simulation analyses and experimental outcomes affirm that our proposed method significantly enhances the performance of the DPI system by eliminating NMR and improving measurement precision. The Allan deviation of our method consistently remains lower than the DPI measurement results under identical conditions over an average time of 125 s, achieving 7.43 nm at 125 s. This method holds promising potential for application in emerging fields such as optical coherence tomography (OCT), long-distance ranging, and precision light detection and ranging (LIDAR). © 2024 American Chemical Society.

  Affiliations:(1) Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), Chongqing University, Chongqing; 400044, China; (2) State Key Laboratory of Transient Optics and Photonics, Xi’an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi’an; 710119, China; (3) School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology, Xi'an; 710021, China; (4) Department of Physics, City University of Hong Kong, Hong Kong; 999077, Hong Kong; (5) CNPC Research Institute of Safety and Environment Technology, Beijing; 10026, China

  Publication Year:2024

  Volume:11

  Issue:7

  Start Page:2673-2680

  DOI Link:10.1021/acsphotonics.4c00475

  数据库ID（收录号）:20242816662390
• Record 402 of
  
  Title:Optical Design of High-compression Ratio and Low-wavefront Error Gravitational Wave Detection Telescope
  
  Author Full Names:Liang, Rong(1,2); Zhou, Xiaojun(1); Zou, Chunbo(3); Xu, Huangrong(1); Li, Chenxi(1); Yu, Tao(1,2); Yu, Weixing(1,2)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:Since the first detection of gravitational wave，gravitational wave astronomy has advanced swiftly. As a crucial component of the detection system，the gravitational wave telescope is obviously crucial. The highly stable laser telescope with a low wavefront error and a high suppression ratio of stray light is a crucial medium for the detection of gravitational waves，as it must not only transmit energy in the order of watt to distant spacecraft，but also receive weak laser signals in the order of picowatt from other satellite base station located millions of kilometers away. Therefore，the backward stray light of the local telescope is required to reach 10−10 orders of the incident laser power. Considering the requirements of small size，light weight，and high compactness，it is clear that the benefits of a reflective system cannot be compared to those of a transmission design. In general，the coaxial Cassegrain structure and off-axis multi-mirror structure are utilized. The off-axis design is preferred over the coaxial design for gravitational wave telescopes due to advantages such as the ability to optimize multiple parameters，the absence of a central obstruction，and the high energy collection capacity. In this paper，based on the design of off-axis four-mirror and the theory of coaxial reflection system，we designed and optimized the telescope combined with the characteristics of high magnification，low wavefront error and high suppression ratio of stray light. In the capture field of view of ±200 µrad，we realized the compression ratio of 100 of telescope，and the entrance pupil diameter of the principle system is 300 mm，whose design result of wavefront error is less than of λ/80 because the actual outgoing wavefront error must be less than λ/40. The system distortion of the edge field is less than 0.056 9%. In order to verify the processing and alignment of the principle system as well as the ability of stray light suppression of it，a 0.5 times scale system is established beneath the system with a wavefront error less than λ/175. Internal stray light is suppressed by increasing the light turning angle between the tertiary mirror and quaternary mirror on the condition of low wavefront error of λ/80. The optimized deflection angle of the tertiary mirror is 5.5 degrees，and the tertiary mirror is the plane surface，which can significantly reduce the difficulty of processing and alignment. A simulation of stray light is applied to analyze the stray light of our designed telescope. The steps of stray light analysis consist of the following steps：1）selection and optimization of the optical structure；2）model setting of the corresponding reflection，scattering，and absorption surfaces；3）stray light analysis of the entire system；4）iterative optimization design；5）fulfillment of the system's requirements. Therefore，we investigated the optical paths and power of the backscattered stray light. After positioning the field stop in the middle image plane between the secondary mirror and the tertiary mirror，the proportion of the stray light caused by the secondary mirror is the smallest. The stray light energy caused by the tertiary mirror and the quaternary mirror is the largest，which can reach more than 90%. The tolerance of the optical design is also analyzed，and the results of the analysis indicate that the tolerance of the parabolic primary mirror has the strongest impact on the wavefront error of the system. The principle system has a 90% cumulative probability wavefront error less than λ/40，which can satisfy the design requirement of gravitational wave detection and have the potential to play a significant role in future missions aimed at low wavefront error，high magnification and a high suppression ratio of stray light in the telescope while detecting gravitational waves. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics Precision Mechanics of Chinese Academy of Sciences, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Fuzhou University, Fuzhou; 350116, China

  Publication Year:2024

  Volume:53

  Issue:1

  Article Number:0122002

  DOI Link:10.3788/gzxb20245301.0122002

  数据库ID（收录号）:20240815579474
• Record 403 of
  
  Title:Design of an Integrated Optical System for Detection and Imaging of Large Aperture and Long Focal Length Based on Continuous Zoom
  
  Author Full Names:Wei, Jinyang(2); Li, Xuyang(1,2); Tan, Longyu(2,3); Yuan, Hao(1); Ren, Zhiguang(1,2); Zhao, Jiawen(1,2); Yao, Kaizhong(1,2)

  Source Title:Guangzi Xuebao/Acta Photonica Sinica

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:In space target observation missions,there is a need for highly sensitive target detection and high-quality imaging. However,there is a significant disparity in the field of view between detection and imaging,and currently,two primary solutions are predominantly employed. One approach involves the design of two independent subsystems,while the other method utilizes a shared-aperture dual-channel design to integrate the functions of detection and imaging into a single system. However,designing two independent systems necessitates a substantial amount of space to accommodate these two subsystems, often exceeding the carrying capacity of most existing space optical payloads. On the other hand,adopting the shared-aperture dual-channel system requires additional electronic components and structural elements,with challenges during the assembly and calibration processes. This may potentially lead to uneven energy distribution issues. In order to achieve high sensitivity detection and precise identification of space targets,this paper introduces the design of an optical system based on a continuous zoom structure that balances a large aperture with a long focal length. This system aims to achieve short focal length and wide-field target detection,as well as long focal length and narrow-field target imaging. In terms of the design methodology,the inherent complexity of the system makes it challenging to obtain an ideal structure during the optimization process. Consequently,this system combines the structures of reflective mirrors and corrective lenses with a zoom structure through optical pupil matching. It employs two reflective mirrors to compress the optical path. During the zooming process,both the zooming components and compensating components move together to maintain the position of the image plane. At the intermediate zoom position,image quality is excellent,allowing for continuous target tracking. To address the issue of uneven energy distribution within the system,this optical system utilizes a shared-aperture detection and imaging integration structure. Furthermore,with an aperture size of 280 mm,the system can detect targets as faint as magnitude 14,effectively resolving the challenges associated with detecting faint and weak targets. The system operates within the spectral range of 450 nm to 850 nm and focal lengths ranging from 700 mm to 3 500 mm. At the detection end,the focal length is 700 mm,with an F-number of 2.5 and a field of view angle of 0.5°×0.5°. At the imaging end,the focal length varies from 1 400 mm to 3 500 mm, with F-numbers ranging from 5 to 12.5 and a field of view angle of 0.18° ×0.18° . At the detection end, 80% of the optical spot's encircled energy is concentrated within 17.4 μm. At the imaging end,the edge field MTF is 0.36,approaching the diffraction limit,while at the intermediate zoom position,MTF values range from 0.31 to 0.36,ensuring consistent image quality during the zooming process. This system integrates the detection and imaging systems into a single unit,achieving shared-aperture functionality. After conducting tolerance analysis on the system,it was observed that under relatively loose tolerances, MTF degradation in both the sagittal and tangential directions is minimal. Moreover, at an 80% probability,the optical spot diameter is smaller than 18.4 μm for each field of view,indicating that the system maintains excellent detection and imaging performance even under these relaxed tolerance conditions. The zoom cam curve is a critical design parameter for zoom systems,and in this system,the cam curves for both the zoom and compensator groups have an apex angle of less than 30°,meeting the design requirements. This system offers strong detection capabilities,excellent image quality,a compact overall length,and a minimal zoom cam curve apex angle. In terms of structure and design objectives,it provides valuable insights for the future development of continuous tracking integrated optical systems for the detection and imaging of targets. © 2024 Chinese Optical Society. All rights reserved.

  Affiliations:(1) Space Optics Technology Lab, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Shanghai Aerospace Control Technology Research Institute, Shanghai; 201109, China

  Publication Year:2024

  Volume:53

  Issue:1

  Article Number:0122001

  DOI Link:10.3788/gzxb20245301.0122001

  数据库ID（收录号）:20240815570755
• Record 404 of
  
  Title:A novel demodulation method of the channeled modulated polarization imaging pictures by hybrid feature modulated autoencoders
  
  Author Full Names:Zhang, Ning(1); Zhao, Mingfan(1,2); Zhang, Zhinan(1); Liu, Jie(1); Zhang, Yunyao(3); Li, Siyuan(1)

  Source Title:Optics Express

  Language:English

  Document Type:Journal article (JA)

  Abstract:Channeled modulated polarization imaging technology offers advantages owing to its simple structure and low cost. However, the loss of high-frequency information due to channel crosstalk and the filter demodulation method has consistently hindered the mature application of this technology. We analyzed the data structure of pictures detected using this technology and proposed a demodulation method using hybrid feature modulated autoencoders. Training the network with a substantial number of images, it effectively addresses the issue of high-frequency information loss and demonstrates proficient demodulation capabilities for both simulated and real detected pictures. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics of CAS, Xi'an; 710119, China; (2) School of Integrated Circuits, Sun Yat-sen University, Shenzhen; 518107, China; (3) College of Information Science and Technology, Northwest University, Xi'an; 710126, China

  Publication Year:2024

  Volume:32

  Issue:18

  Start Page:31473-31484

  DOI Link:10.1364/OE.530310

  数据库ID（收录号）:20243516970851
• Record 405 of
  
  Title:The Active Alignment Technology for Off-axis Three-mirror Optical system
  
  Author Full Names:Lei, Yu(1,2); He, Tian(3); Ma, Caiwen(1,2); Li, Zhiguo(1,2)

  Source Title:Proceedings of SPIE - The International Society for Optical Engineering

  Language:English

  Document Type:Conference article (CA)

  Conference Title:Advanced Optical Manufacturing Technologies and Applications 2024, AOMTA 2024 and 4th International Forum of Young Scientists on Advanced Optical Manufacturing, YSAOM 2024

  Conference Date:July 5, 2024 - July 7, 2024

  Conference Location:Xi'an, China

  Conference Sponsor:Advanced Optical Manufacturing Youth Expert Committee, CSOE; Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Fudan University; University of Shanghai for Science and Technology; Xi'an Institute of Optics and Precision Mechanics of CAS; Xi'an Technological University

  Abstract:The off-axis three-mirror optical system is a typical class of off-axis systems. In order to ensure excellent imaging quality in the full field of view, the alignment process involves multiple components with multiple degrees of freedom which is difficult and challenging. This article focuses on the research of automatic adjustment technology for the off-axis three-mirror optical system. By quantitatively studying the relationship between component misalignment and aberrations, we aim to explore alignment method for this type of system, providing effective and reliable methods for active adjustment. The method studied in this paper has been verified on an off-axis three-mirror optical system, achieving a full-field RMS better than 0.05@632.8nm, reaching the diffraction limit. © 2024 SPIE.

  Affiliations:(1) Xi'an Institute of Optics and Precision Mechanics, CAS, NO.17 Xinxi Road, Xi'an Hi-Tech Industrial Development Zone, Shaanxi, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing; 100049, China; (3) Xi'an University of Technology, Jinhua South Road No. 5, Beilin District, Shaanxi, Xi'an; 710048, China

  Publication Year:2024

  Volume:13280

  Article Number:132801H

  DOI Link:10.1117/12.3048315

  数据库ID（收录号）:20244917482146
• Record 406 of
  
  Title:Research on MRTD objective testing method based on machine learning
  
  Author Full Names:Ji, Ran(1,2); Xiao, Maosen(1); Li, Shuo(1,2); Liu, Yu(1,3); Luo, Zhanyi(1,3); Cheng, Jiawei(1,3)

  Source Title:Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics

  Language:Chinese

  Document Type:Journal article (JA)

  Abstract:The accelerated development of infrared imaging technology has put forward more stringent requirements for the objectivity and accuracy of the testing and evaluation of infrared imaging systems. Aiming at the current problems of test subjectivity and operational complexity of the minimum resolvable temperature difference (MRTD) of infrared imaging systems, two MRTD objective test methods based on support vector machine (SVM) and convolutional neural network (CNN) are proposed. By introducing the data enhancement technique, the overfitting caused by the small training samples and the complex network hierarchy is avoided. The experimental results show that compared with the actual personnel's judgment of the data, the MRTD test using the SVM method has a recognition accuracy of 94. 50% and a training time of 8. 22 s. while the CNN method has an average accuracy of 99. 07% in three training sessions, and a training time of 487. 48 s for 100 iterations. The SVM method has better real-time performance and the CNN method is characterized by high accuracy. The experimental result verifies that these two objective test methods of MRTD provide a tool for quantification and evaluation of infrared thermal imaging system performance indicators research. © 2024 Chinese Institute of Electronics. All rights reserved.

  Affiliations:(1) Xi'An Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Xi'an; 710119, China; (2) School of Optoelectronics, University of Chinese Academy of Sciences, Beijing; 100049, China; (3) School of Physics and Information Technology, Shaanxi Normal University, Xi'an; 710119, China

  Publication Year:2024

  Volume:46

  Issue:10

  Start Page:3265-3270

  DOI Link:10.12305/j.issn.1001-506X.2024.10.03

  数据库ID（收录号）:20244517309578
• Record 407 of
  
  Title:A semi-supervised cross-modal memory bank for cross-modal retrieval
  
  Author Full Names:Huang, Yingying(1,2,3); Hu, Bingliang(3); Zhang, Yipeng(1,2,3); Gao, Chi(1,2,3); Wang, Quan(1,3)

  Source Title:Neurocomputing

  Language:English

  Document Type:Journal article (JA)

  Abstract:The core of semi-supervised cross-modal retrieval tasks lies in leveraging limited supervised information to measure the similarity between cross-modal data. Current approaches assume an association between unlabelled data and pre-defined k-nearest neighbour data, relying on classifier performance for this selection. With diminishing labelled data, classifier performance weakens, resulting in erroneous associations among unlabelled instances. Moreover, the lack of interpretability in class probabilities of unlabelled data hinders classifier learning. Thus, this paper focuses on learning pseudo-labels for unlabelled data, providing pseudo-supervision to aid classifier learning. Specifically, a cross-modal memory bank is proposed, dynamically storing feature representations in a common space and class probability representations in a label space for each cross-modal data. Pseudo-labels are derived by computing feature representation similarity and adjusting class probabilities. During this process, imposing constraints on the classification loss between labelled data and contrastive losses between paired cross-modal data is a prerequisite for the successful learning of pseudo-labels. This procedure significantly contributes to enhancing the credibility of these pseudo-labels. Empirical findings demonstrate that using only 10% labelled data, compared to prevailing semi-supervised techniques, this method achieves improvements of 2.6%, 1.8%, and 4.9% in MAP@50 on the Wikipedia, NUS-WIDE, and MS-COCO datasets, respectively. © 2024

  Affiliations:(1) Key Laboratory of Spectral Imaging Technology, Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, Shaanxi, Xi'an; 710119, China; (2) University of Chinese Academy of Sciences, Beijing; 100049, China; (3) Key laboratory of Biomedical Spectroscopy, Shaanxi, Xi'an; 710119, China

  Publication Year:2024

  Volume:579

  Article Number:127430

  DOI Link:10.1016/j.neucom.2024.127430

  数据库ID（收录号）:20241015679996
• Record 408 of
  
  Title:Effective correction of dissolved organic carbon interference in nitrate detection using ultraviolet spectroscopy combined with the equivalent concentration offset method
  
  Author Full Names:Dong, Jing(1,2); Tang, Junwu(1,3); Wu, Guojun(1,3); Xin, Yu(4); Li, Ruizhuo(1,2); Li, Yahui(3)

  Source Title:RSC Advances

  Language:English

  Document Type:Journal article (JA)

  Abstract:Nitrate contamination in water sources poses a substantial environmental and health risk. However, accurate detection of nitrate in water, particularly in the presence of dissolved organic carbon (DOC) interference, remains a significant analytical challenge. This study investigates a novel approach for the reliable detection of nitrate in water samples with varying levels of DOC interference based on the equivalent concentration offset method. The characteristic wavelengths of DOC were determined based on the first-order derivatives, and a nitrate concentration prediction model based on partial least squares (PLS) was established using the absorption spectra of nitrate solutions. Subsequently, the absorption spectra of the nitrate solutions were subtracted from that of the nitrate-DOC mixed solutions to obtain the difference spectra. These difference spectra were introduced into the nitrate prediction model to calculate the equivalent concentration offset values caused by DOC. Finally, a DOC interference correction model was established based on a binary linear regression between the absorbances at the DOC characteristic wavelengths and the DOC-induced equivalent concentration offset values of nitrate. Additionally, a modeling wavelength selection algorithm based on a sliding window was proposed to ensure the accuracy of the nitrate concentration prediction model and the equivalent concentration offset model. The experimental results demonstrated that by correcting the DOC-induced offsets, the relative error of nitrate prediction was reduced from 94.44% to 3.36%, and the root mean square error of prediction was reduced from 1.6108 mg L−1 to 0.1037 mg L−1, which is a significant correction effect. The proposed method applied to predict nitrate concentrations in samples from two different water sources shows a certain degree of comparability with the standard method. It proves that this method can effectively correct the deviations in nitrate measurements caused by DOC and improve the accuracy of nitrate measurement. © 2024 The Royal Society of Chemistry.

  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) Laoshan Laboratory, Qingdao; 266237, China; (4) Ocean University of China, Qingdao; 266100, China

  Publication Year:2024

  Volume:14

  Issue:8

  Start Page:5370-5379

  DOI Link:10.1039/d3ra08000e

  数据库ID（收录号）:20240815567105