2024

• Record 121 of
  
  Title:Analysis of laser interference backward stray light based on TianQin space gravitational wave detection
  
  Author(s):Yan, Haoyu(1,2,3); Chen, Qinfang(1,3); Ma, Zhanpeng(1,3); Wang, Hu(1,2,3)
  Source:Journal of Astronomical Telescopes, Instruments, and Systems
  Volume: 10  Issue: 3  DOI: 10.1117/1.JATIS.10.3.034007  Published: July 1, 2024  
  Abstract:According to the working principle of the telescope, we know that the telescope requires stray light from the system to reach the order of 10-10 of the output laser power. In this article, given the roughness of the M1 mirror of 3 and the roughness of the M2M4 mirror of 1.8 , through separate analysis of the four mirror surfaces, we found that M4 has the greatest impact on the backward stray light of the telescope, and as the angle of M4 incident light increases, the level of stray light in the system decreases; after adjusting the M4 incidence angle and considering only the roughness, the stray light level of the telescope system reaches 10-11 of the power of the outgoing laser, which meets the expected requirements. Subsequently, we calculated the impact of particle pollution on the stray light of the system, and based on our analysis results, we determined that the cleanliness level of the telescope testing and storage environment was better than 100. Then, we conducted surface defect calculations and obtained the surface defect requirements for M1 to M4, and it is concluded that as the scattering angle decreases, the main contribution of bidirectional reflectance distribution function (BRDF) changes from geometric optics to diffraction effects. Finally, we conducted actual measurements on the surface quality of the ultra-smooth mirror sample, and the measured BRDF value was substituted into the simulation analysis, resulting in a telescope stray light of 8.29×10-11, meeting the expected requirements. © 2024 Society of Photo-Optical Instrumentation Engineers (SPIE).
  Accession Number: 20244217187147
• Record 122 of
  
  Title:High-performance architecture for real-time high-definition short-wave infrared streaming video processing and its field programmable gate array prototype
  
  Author(s):Zhou, Feng(1,2,3); Chen, Zhiqiang(1,2,3); Xie, Qingsheng(1,3); Kong, Fanzi(1,2,3); Chen, Yaohong(1,3); Wang, Huawei(1,3)
  Source:Optical Engineering
  Volume: 63  Issue: 2  DOI: 10.1117/1.OE.63.2.023103  Published: February 1, 2024  
  Abstract:Image detail enhancement is critical to the performance of short-wave infrared (SWIR) imaging systems. Recently, the requirement for real-time processing of high-definition (HD) SWIR video has shown rapid growth. Nevertheless, the research on field programmable gate array (FPGA) implementation of HD SWIR streaming video processing architecture is relatively few. This work proposes a real-time FPGA architecture of SWIR video enhancement by combining the difference of Gaussian filter and plateau equalization. To accelerate the algorithm and reduce memory bandwidth, two efficient key architectures, namely edge information extraction and equalization and remapping architecture, are proposed to sharpen edges and improve dynamic range. The experimental results demonstrated that the proposed architecture achieved a real-time processing of 1280 × 1024@60Hz with 2.7K lookup tables, 2.5K Slice Reg, and about 350 kb of block RAM consumption, and their utilization reached 12.5%, 19.2%, and 12.5% for the XC7A200T FPGA board, respectively. Moreover, the proposed architecture is fully pipelined and synchronized to the pixel clock of output video, meaning that it can be seamlessly integrated into diverse real-time video processing systems. © 2024 Society of Photo-Optical Instrumentation Engineers (SPIE)
  Accession Number: 20241115712686
• Record 123 of
  
  Title:Structural vibration frequency monitoring based on event camera
  
  Author(s):Lv, Yuanyuan(1,2,3); Zhou, Liang(1,3); Liu, Zhaohui(1,3); Zhang, Haiyang(1,2,3)
  Source:Measurement Science and Technology
  Volume: 35  Issue: 8  DOI: 10.1088/1361-6501/ad42bf  Published: August 2024  
  Abstract:Compared with traditional cameras, event cameras (ECs) have the significant advantages of high temporal resolution, low data redundancy, and microsecond delay, which are beneficial in structural monitoring to extract the dense response of structures in both spatial and temporal dimensions. In this paper, the vibration frequency detection method based on ECs is studied. This study investigates vibration frequency detection methods based on ECs, and proposes two algorithms for vibration frequency detection based on event streams: marker tracking and event count. Experimental verification is conducted through forced vibration experiments. The results indicate that the event count method achieves high-precision measurement of vibration frequencies in the range of 10-190 Hz for different vibration scales, with a maximum relative error of 1% and an average relative error of 0.673%. The marker tracking method demonstrates a maximum relative error of 1.43% and an average relative error of 0.575% in frequency measurement for large-amplitude vibrations. However, as the amplitude decreases, the frequency measurement error increases. When the amplitude is less than 3 pixels, the frequency measurement error exceeds 30%, rendering the measurement results unreliable. This research provides technical support for high-precision structural vibration frequency monitoring and further expands the application of ECs in structural monitoring. © 2024 IOP Publishing Ltd.
  Accession Number: 20242116106596
• Record 124 of
  
  Title:Parallel adaptive RBF neural network-based active disturbance rejection control for hybrid compensation of PMSM
  
  Author(s):Gao, Peng(1,2,3); Su, Xiuqin(1,4); Pan, Zhibin(2); Xiao, Maosen(1); Zhang, Wenbo(1,2,3)
  Source:Robotic Intelligence and Automation
  Volume: 44  Issue: 5  DOI: 10.1108/RIA-03-2023-0036  Published: August 29, 2024  
  Abstract:Purpose: This study aims to promote the anti-disturbance and tracking accuracy performance of the servo systems, in which a modified active disturbance rejection control (MADRC) scheme is proposed. Design/methodology/approach: An adaptive radial basis function (ARBF) neural network is utilized to estimate and compensate dominant friction torque disturbance, and a parallel high-gain extended state observer (PHESO) is employed to further compensate residual and other uncertain disturbances. This parallel compensation structure reduces the burden of single ESO and improves the response speed of permanent magnet synchronous motor (PMSM) to hybrid disturbances. Moreover, the sliding mode control (SMC) rate is introduced to design an adaptive update law of ARBF. Findings: Simulation and experimental results show that as compared to conventional ADRC and SMC algorithms, the position tracking error is only 2.3% and the average estimation error of the total disturbances is only 1.4% in the proposed MADRC algorithm. Originality/value: The disturbance parallel estimation structure proposed in MADRC algorithm is proved to significantly improve the performance of anti-disturbance and tracking accuracy. © 2024, Emerald Publishing Limited.
  Accession Number: 20243116800960
• Record 125 of
  
  Title:Multinetwork Algorithm for Coastal Line Segmentation in Remote Sensing Images
  
  Author(s):Li, Xuemei(1); Wang, Xing(2); Ye, Huping(3); Qiu, Shi(4); Liao, Xiaohan(5)
  Source:IEEE Transactions on Geoscience and Remote Sensing
  Volume: 62  Issue:   DOI: 10.1109/TGRS.2024.3435963  Published: 2024  
  Abstract:The demarcation between the sea and the land, commonly referred to as the coastline, is of paramount importance for the dynamic monitoring of its alterations. This monitoring is essential for the effective utilization of marine resources and the conservation of the ecological environment. Addressing the challenges posed by the extensive expanse of coastal lines, which can complicate their acquisition and processing, this study utilizes remote sensing imagery to introduce an algorithm for coastal line segmentation. The algorithm integrates multiple networks to enhance its effectiveness. Innovations encompass the development of an extraction algorithm for coastal lines that are as follows. First, utilize an attention-guided conditional generative adversarial network (AC-GAN) model, which redefines the task of image segmentation by framing it as a style transformation problem. Second, a strategy for coastal line segmentation utilizes Dense Swin Transformer Unet (DSTUnet) to construct a densely structured model. This approach integrates Transformer to prioritize focal regions, thereby enhancing image and semantic interpretation. Third, a transfer learning framework is proposed to integrate multiple features, leveraging the strengths of different networks to achieve accurate segmentation of coastal lines. The study introduced two datasets, and the experimental results confirm that parallel network configurations and asymmetric weighting are superior in achieving optimal results, with an area overlap measure (AOM) score of 85%, outperforming the Unet by 5%. © 1980-2012 IEEE.
  Accession Number: 20243216813662
• Record 126 of
  
  Title:Fourier ptychographic microscopy with adaptive resolution strategy
  
  Author(s):Xu, Jinghao(1,2); Feng, Tianci(1,2); Wang, Aiye(1,2); Xu, Fannuo(1,2); Pan, An(1,2)
  Source:Optics Letters
  Volume: 49  Issue: 13  DOI: 10.1364/OL.525289  Published: July 1, 2024  
  Abstract:Fourier ptychographic microscopy (FPM) is a method capable of reconstructing a high-resolution, wide field-of-view (FOV) image, where dark-field images provide the high-frequency information required for the iterative process. Theoretically, using more dark-field images can lead to results with higher resolution. However, the resolution required to clearly detect samples with different microscales varies. For certain samples, the limit resolution of the imaging system may exceed the one required to resolve the details. This suggests that simply increasing the number of dark-field images will not improve the recognition capability for such samples and may instead significantly increase the computational cost. To address this issue, this Letter proposes an adaptive resolution strategy that automatically assigns the resolution required for the sample. Based on a Tenengrad approach, this strategy determines the number of images required for reconstruction by evaluating a series of differential images among the reconstructions for a certain subregion and then efficiently completes the full-FOV reconstruction according to the determined resolution. We conducted the full-FOV reconstruction utilizing feature-domain FPM for both the USAF resolution test chart and a human red blood cell sample. Employing the adaptive resolution strategy, the preservation of reconstruction resolution can be ensured while respectively economizing approximately 76% and 89% of the time. © 2024 Optica Publishing Group.
  Accession Number: 20242816657521
• Record 127 of
  
  Title:Topology Optimization with Explicit Components Considering Stress Constraints
  
  Author(s):Ma, Yubao(1,2); Li, Zhiguo(1); Wei, Yuxuan(1,2); Yang, Kai(1,2)
  Source:Applied Sciences (Switzerland)
  Volume: 14  Issue: 16  DOI: 10.3390/app14167171  Published: August 2024  
  Abstract:Topology optimization focuses on the conceptual design of structures, characterized by a large optimization space and a significant impact on structural performance, and has been widely applied in industrial fields such as aviation and aerospace. However, most topology optimization methods prioritize structural stiffness and often overlook stress levels, which are critical factors in engineering design. In recent years, explicit topology optimization methods have been extensively developed due to their ability to produce clear boundaries and their compatibility with CAD/CAE systems. Nevertheless, research on incorporating stress constraints within the explicit topology optimization framework remains scarce. This paper is dedicated to investigating stress constraints within the explicit topology optimization framework. Due to the clear boundaries and absence of intermediate density elements in the explicit topology optimization framework, this approach avoids the challenge of stress calculation for intermediate density elements encountered in the traditional density method. This provides a natural advantage in solving topology optimization problems considering stress constraints, resulting in more accurate stress calculations. Compared with existing approaches, this paper proposes a novel component topology description function that enhances the deformability of components, improving the representation of geometric boundaries. The lower-bound Kreisselmeier–Steinhauser aggregation function is employed to manage the stress constraint, reducing the solution scale and computational burden. The effectiveness of the proposed method is demonstrated through two classic examples of topology optimization. © 2024 by the authors.
  Accession Number: 20243516964969
• Record 128 of
  
  Title:Investigation on multi-objective optimization for in-situ laser-assisted machining of glass-ceramic
  
  Author(s):Fan, Mingxu(1); Sun, Guoyan(1); Ding, Jiaoteng(1); Song, Jinzhou(2)
  Source:Applied Physics A: Materials Science and Processing
  Volume: 130  Issue: 10  DOI: 10.1007/s00339-024-07911-y  Published: October 2024  
  Abstract:As a typical optical hard and brittle material, the efficient machining methods of glass-ceramic have always been a research hotspot. Based on previous research, this article conducted surface damage analysis on glass-ceramic using in-situ laser-assisted machining (LAM) orthogonal experimental results, and summarized that the surface damage of glass-ceramic mainly includes scratches, pits, and brittle fracture. Surface analysis confirmed that in-situ LAM can effectively reduce cutting forces and improve surface quality compared to conventional cutting. The artificial neural network (ANN) and genetic algorithm (GA) were used to fit and train and conduct multi-objective optimization for the data from in-situ LAM orthogonal experiments with resultant cutting force and surface roughness as eigenvalues. The Pareto optimal front curve with multiple groups of optimal solutions was obtained through multi-objective optimization using GA. The actual in-situ LAM experimental values were compared with the predicted values in the Pareto front, the relative error of the resultant force and the relative error of the surface roughness are both very small. In-situ LAM experiments based on response surface methodology (RSM) with surface roughness as the characteristic value were conducted. The optimal machining parameters for RSM optimization, as well as the minimum values for resultant force and surface roughness were obtained. Through comparative analysis, it was found that RSM has better multi-objective optimization performance than GA. Research content of this article provides reference and guidance for the multi-objective optimization analysis method of hard and brittle materials such as glass-ceramic after LAM. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.
  Accession Number: 20243917111334
• Record 129 of
  
  Title:Spectral encoder to extract the efficient features of Raman spectra for reliable and precise quantitative analysis
  
  Author(s):Gao, Chi(1,2,3); Fan, Qi(1,2); Zhao, Peng(1,2,3); Sun, Chao(1,2); Dang, Ruochen(1,2,3); Feng, Yutao(1); Hu, Bingliang(1,2); Wang, Quan(1,2)
  Source:Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
  Volume: 312  Issue:   DOI: 10.1016/j.saa.2024.124036  Published: May 5, 2024  
  Abstract:Raman spectroscopy has become a powerful analytical tool highly demanded in many applications such as microorganism sample analysis, food quality control, environmental science, and pharmaceutical analysis, owing to its non-invasiveness, simplicity, rapidity and ease of use. Among them, quantitative research using Raman spectroscopy is a crucial application field of spectral analysis. However, the entire process of quantitative modeling largely relies on the extraction of effective spectral features, particularly for measurements on complex samples or in environments with poor spectral signal quality. In this paper, we propose a method of utilizing a spectral encoder to extract effective spectral features, which can significantly enhance the reliability and precision of quantitative analysis. We built a latent encoded feature regression model; in the process of utilizing the autoencoder for reconstructing the spectrometer output, the latent feature obtained from the intermediate bottleneck layer is extracted. Then, these latent features are fed into a deep regression model for component concentration prediction. Through detailed ablation and comparative experiments, our proposed model demonstrates superior performance to common methods on single-component and multi-component mixture datasets, remarkably improving regression precision while without needing user-selected parameters and eliminating the interference of irrelevant and redundant information. Furthermore, in-depth analysis reveals that latent encoded feature possesses strong nonlinear feature representation capabilities, low computational costs, wide adaptability, and robustness against noise interference. This highlights its effectiveness in spectral regression tasks and indicates its potential in other application fields. Sufficient experimental results show that our proposed method provides a novel and effective feature extraction approach for spectral analysis, which is simple, suitable for various methods, and can meet the measurement needs of different real-world scenarios. © 2024 Elsevier B.V.
  Accession Number: 20240815597901
• Record 130 of
  
  Title:Optical design of a 5× zoom afocal telescope with deformable mirrors
  
  Author(s):Zou, Gangyi(1,2); Fan, Xuewu(1); Zhao, Hui(1); Pang, Zhihai(1); Xie, Xiaopeng(1); Xu, Liang(1)
  Source:Optics Express
  Volume: 32  Issue: 20  DOI: 10.1364/OE.537331  Published: September 23, 2024  
  Abstract:All-reflective zoom afocal telescopes can be integrated with existing imaging systems as foreoptics, enabling flexible imaging with adjustable resolution. This paper proposes an approach to designing a 5× zoom afocal telescope using deformable mirrors. Based on matrix optics, the first-order parameters for a coaxial reflective 5× zoom afocal telescope with a fixed primary mirror and three deformable mirrors are determined. To prevent obscuration, the mirrors are tilted at their vertices, which introduces asymmetric aberrations. To correct these aberrations, XY polynomial surfaces are employed on the primary mirror and an additional flat fold mirror. The final design and image simulations indicate that the system achieves good image quality across all zoom positions, enabling 5× zoom imaging with a maximum root mean square wavefront error of less than 0.125λ (λ = 632.8 nm), thereby validating the efficacy of the proposed design methodology. © 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.
  Accession Number: 20244017148692
• Record 131 of
  
  Title:30× VIS-SWIR wideband zoom lens design (invited)
  
  Author(s):Qu, Rui(1); Zhang, Hongwei(1); Guo, Huinan(1); Li, Jian(2)
  Source:Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering
  Volume: 53  Issue: 10  DOI: 10.3788/IRLA20240296  Published: October 2024  
  Abstract:Objective High function density electro-optical (EO) system is becoming an important development direction at present and in the near future. With the gradual maturity of wide-band infrared detector technology, VIS-SWIR (from visible to short wave infrared) wide-band confocal zoom optical system， which can support various operational modes such as color imaging, fog penetration, and low-light conditions, effectively simplify the overall design of EO systems, turns into an important mean to realize the high functional density and SWaP&C (Size, Weight, Power, and Cost) of EO system, but optical materials show great differences in dispersion characteristics within this band, which makes design of continuous zoom system difficult and time-consuming. Studying of the corresponding optical system design method become necessary and urgent. Methods In order to solve this problem, a wide band zoom optical design model (Eq. (1)-Eq. (3)) is established with the combination of classical continuous zoom system design model and the achromatic conditions in the design of wide-band optical system. The parameters affecting the color aberration distribution of the whole system are explicitly demonstrated in the model. Based on the proposed model, the methods of optical power distribution and material selection are further discussed. Considering the dispersion characteristics of glass materials in different bands, some material using guidelines with examples in Tab.1 of wideband zoom lens design is provided. The extraordinary applications of the cemented elements, especially the synthetic abnormal dispersion characteristics and its synthetic method, are pointed out explicitly. Results and Discussions A wideband (VIS-SWIR) optical system under the requirements of F≤5.5, focal length 10-300 mm, horizontal field of view 38.8°-1.25°, waveband of 0.48-1.7 μm, 1 080 P InGaAs detector with pixel size of 3.45 μm is designed (Fig.3) to fulfill multi-band imaging by switching filters, and realize the common aperture integration of different functions such as color/fog-penetrating/laser/low-light imaging through a switching mechanism or a dichroic prism (Fig.4-Fig.5). It can be observed from Tab.3 that at a frequency of 100 lp/mm and 145 lp/mm, the MTF values at the edge of the field of view are approximately 0.3 and 0.1 across the wide wavelength range of 0.48 μm to 1.7 μm, the relative distortion at each focal length position is less than 2%; the chromatic focus shift at each focal length position is within the focal depth (162 μm) as 1.1 μm is taken as the central wavelength. The zoom lens system, which uses 7 kinds of optical glass, consists of 18 lenses, total length 190 mm, has good image quality and tolerance character through the full zoom range. Conclusions Starting from the zoom system design model, a design method for a wide-band zoom system is discussed with consideration of the achromatic conditions within and between bands of a wide-band system. Material selection criteria for different components of the zoom system are provided, which reduces the time-consuming and tedious trial-and-error process of traditional methods. This approach can effectively guide the design and development of related optical systems. As an example, a continuous zoom optical system with a wide wavelength range of 0.48 μm to 1.7 μm is designed using only commonly used optical glass. This system achieves integration of a common aperture and common focal plane for the visible light, near-infrared, and short-wave infrared bands. It features a telephoto ratio better than 0.64 and a zoom ratio of 30×. Additionally, it demonstrates excellent imaging quality throughout the entire zoom range and is compatible with multi-band, multi-mode, and multi-purpose applications, making it promising for widespread use in related fields. © 2024 Chinese Society of Astronautics. All rights reserved.
  Accession Number: 20244317254928
• Record 132 of
  
  Title:Spectral imaging based on custom-made multi-strip filter arrays
  
  Author(s):Guo, Quan(1,2); Wu, Dengshan(1); Yu, Weixing(1,2)
  Source:Applied Optics
  Volume: 63  Issue: 13  DOI: 10.1364/AO.522642  Published: May 1, 2024  
  Abstract:Spectral imaging technology based on on-chip spectroscopy can find applications in areas including aerospace, industrial and consumer electronics, and so on. Since each application normally requires a different set and number of spectral bands, the development of customized spectroscopy solutions with more compact size and lower cost becomes quite important. In this paper, we demonstrate a compact, highly customizable imaging spectrometer scheme based on custom-made multi-strip filter arrays, which maintains an average high transmission of ∼85%, narrow bandwidth of ∼30 nm, and high optical density of ∼OD2 in the blocking regions across the visible to near-infrared waveband. Spectral imaging experiments are conducted, and the accurate reconstruction of sparse spectral image data is demonstrated as well to prove the validity of the proposed scheme. As a result, the work reported in this paper allows researchers to develop customized spectral imaging equipment in a relatively easy way and also has a great potential to be engineered further for scalable production with a quite low cost. © 2024 Optica Publishing Group © 2024 Optica Publishing Group (formerly OSA). All rights reserved.
  Accession Number: 20242016084651