2023
2023
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Record 217 of
Title:Advances in light transverse momenta and optical lateral forces
Author(s):Shi, Yuzhi(1,2,3,4,5); Xu, Xiaohao(6); Nieto-Vesperinas, Manuel(7); Song, Qinghua(8); Liu, Ai Qun(9); Cipparrone, Gabriella(10); Su, Zengping(8); Yao, Baoli(6); Wang, Zhanshan(1,2,3,4,5); Qiu, Cheng-Wei(11); Cheng, Xinbin(1,2,3,4)Source: Advances in Optics and Photonics Volume: 15 Issue: 3 Article Number: null DOI: 10.1364/AOP.489300 Published: September 30, 2023Abstract:Harnessing linear and angular momenta of light is one of the cornerstones in modern optics and has found tremendous applications in optical circuits, particle manipulation, metrology, quantum information processing, etc. Emerging theoretical protocols and experimental explorations have created a surge of interest in light lateral momenta and forces, which are perpendicular to the light wave propagation direction. However, there is yet a lack of a comprehensive and holistic overview of transverse momenta (both linear and angular) as well as of optical lateral forces (OLFs). In this article, we first review the most recent transverse momenta including the transverse spin angular momentum, optical skyrmions, as well as lateral momenta from directional side scattering, spin-orbit interaction, and surface plasmon polaritons. Since optical forces result from the momentum exchange between light and matter, the transverse momentum consequently gives rise to intriguing OLFs, which is the second topic of this article. Additional non-trivial lateral forces that combine optics with other effects from thermodynamics, electricity, and microfluidics, are also discussed. It should be emphasized that these momenta and forces ubiquitously exist in a broad range of optical phenomena and have often been neglected due to their unpredicted underlying physics and shortage of experimental means, especially prior to the last decade. ? 2023 Optica Publishing Group.Accession Number: 20234515032144 -
Record 218 of
Title:Remote Sensing Image Retrieval by Deep Attention Hashing with Distance-Adaptive Ranking
Author(s):Zhang, Yichao(1,2); Zheng, Xiangtao(3); Lu, Xiaoqiang(3)Source: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Volume: 16 Issue: null Article Number: null DOI: 10.1109/JSTARS.2023.3271303 Published: 2023Abstract:With the joint advancement of numerous related fields of remote sensing, the amount of remote sensing data is growing exponentially. As an essential remote sensing Big Data management technique, content-based remote sensing image retrieval has attracted more and more attention. A novel deep attention hashing with distance-adaptive ranking (DAH) is proposed for remote sensing image retrieval in this article. First, a channel-spatial joint attention mechanism is employed for feature extraction of remote sensing images to make the proposed DAH method focus more on the critical details of the remote sensing images and suppress irrelevant regional responses. Second, a novel balanced pairwise weighted loss function is proposed to enable discrete hash codes to participate in neural network training, which contains pairwise weighted similarity loss, classification loss, and quantization loss. The pairwise weighted similarity loss is designed to decrease the impact of the imbalance of positive and negative sample pairs. The classification loss and quantization loss are added to the loss function to decrease background interference and information loss during the quantization phase, respectively. Finally, a distance-adaptive ranking strategy with category-weighted Hamming distance is presented in the retrieval phase to utilize the category probability information fully. Experiments on benchmark datasets compared with state-of-the-art methods demonstrate the effectiveness of the proposed DAH method. ? 2008-2012 IEEE.Accession Number: 20232114130171 -
Record 219 of
Title:Ranging analysis of a moving target based on the dynamic instrument response function
Author(s):Zhao, Yixin(1,2,3); Hao, Wei(1,2,3); Chen, Songmao(1,3); Tian, Yuan(1,2,3); Zhang, Xuan(1,2,3); Xu, Weihao(1,2,3); Zhang, Zhenyang(1,2,3); Wang, Jie(1,2,3); Su, Xiuqin(1,2,3)Source: Optics Letters Volume: 48 Issue: 21 Article Number: null DOI: 10.1364/OL.502505 Published: November 1, 2023Abstract:A ranging high-speed moving target with a high accuracy is challenging for a single-photon ranging system (SPRS). In this Letter, the dynamic instrument response function (IRF) is proposed to establish a dynamic discrete model (DDM) by introducing a velocity and a system timing resolution, which leads to better accuracy of cross-correlation results. And with the data of a dynamic Monte Carlo (DMC), the ranging accuracy can be improved with DDM. ? 2023 Optica Publishing Group.Accession Number: 20234615048246 -
Record 220 of
Title:Structural optimization design and analysis of a 2m space-based mirror
Author(s):Wang, Sheng(1,2); Wang, Wei(1); Hu, Bin(1); Wei, DeJing(1,2); Lin, ShangMin(1); Cheng, PengFei(1); Ren, GuoRui(1); Fan, XueWu(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12639 Issue: null Article Number: 126390N DOI: 10.1117/12.2682098 Published: 2023Abstract:In terms of optical requirements and launch costs, large-diameter mirror should not only ensure fine surface accuracy, but also pursue high the rate of lightweight. Starting with material selection and shape design, the structure design of the 2m mirror of a space remote sensor is carried out, and the preliminary mirror body is obtained. Then, combined with a platform of design optimization called Isight that integrated modeling software, finite element analysis software, data processing and analysis software, we optimized the key structural parameters of the mirror in detail, obtained a SiC mirror with the mass of 178 kg, its the rate of lightweight was as high as 90.9% and the RMS of surface shape accuracy under gravity deformation is 2.2 nm. On this basis, we designed and simulated the flexible support and other mirror components. The results indicated that the first-order natural frequency of the mirror components was 113.8Hz, the RMS of surface shape accuracy was 8.1 nm under gravity deformation when the optical axis is horizontal, and 8.2 nm under the condition of 2 °C temperature change, which were better than λ/60, could meet the requirement of the design index completely. ? 2023 SPIE.Accession Number: 20233714726465 -
Record 221 of
Title:Hyperspectral image classification method based on hierarchical transformer network
Author(s):Zhang, Yichao(1,2); Zheng, Xiangtao(1,3); Lu, Xiaoqiang(1,3)Source: Cehui Xuebao/Acta Geodaetica et Cartographica Sinica Volume: 52 Issue: 7 Article Number: null DOI: 10.11947/j.AGCS.2023.20220540 Published: July 20, 2023Abstract:Hyperspectral image classification, which assigns each pixel to predefined land cover categories, is of crucial importance in various Earth science tasks such as environmental mapping and other related fields. In recent years, scholars have attempted to utilize deep learning frameworks for hyperspectral image classification and achieved satisfactory results. However, these methods still have certain deficiencies in extracting spectral features. This paper proposes a hierarchical self-attention network (HSAN) for hyperspectral image classification based on the self-attention mechanism. Firstly, a skip-layer self-attention module is constructed for feature learning, leveraging the self-attention mechanism of Transformer to capture contextual information and enhance the contribution of relevant information. Secondly, a hierarchical fusion method is designed to further alleviate the loss of relevant information during the feature learning process and enhance the interplay of features at different hierarchical levels. Experimental results on the Pavia University and Houston2013 datasets demonstrate that the proposed framework outperforms other state-of-the-art hyperspectral image classification frameworks. ? 2023 Shanghai Jiaotong University. All rights reserved.Accession Number: 20233414574393 -
Record 222 of
Title:A 50Gb/s CMOS Optical Receiver With Si-Photonics PD for High-Speed Low-Latency Chiplet I/O
Author(s):Chen, Sikai(1,2); You, Mingyang(1,2); Yang, Yunqi(1,2); Jin, Ye(3,4,5); Lin, Ziyi(1,2); Li, Yihong(1,2); Li, Leliang(1,2); Li, Guike(1,2); Xie, Yujun(3,4,5); Zhang, Zhao(1,2); Wang, Binhao(6,7); Tang, Ningfeng(8,9); Liu, Faju(8,9); Fang, Zheyu(10); Liu, Jian(1,2); Wu, Nanjian(1,2); Chen, Yong(11); Liu, Liyuan(1,2); Zhu, Ninghua(3,4,5); Li, Ming(3,4,5); Qi, Nan(1,2)Source: IEEE Transactions on Circuits and Systems I: Regular Papers Volume: 70 Issue: 11 Article Number: null DOI: 10.1109/TCSI.2023.3314446 Published: November 1, 2023Abstract:This paper presents a 50-Gb/s optical receiver (ORX) chipset, consisting of a transimpedance amplifier (TIA) and a clock and data recovery (CDR) circuit in a 45-nm silicon-on-insulator CMOS. The proposed inverter-based TIA employs hybrid shunt-series peaking inductors to extend the bandwidth (BW). A baud-rate CDR is proposed to reduce the sampling phases and clocking power by half. To optimise the ORX for in- package integration, a compact-size digital loop is adopted in each channel, and the clock is recovered by phase interpolation from a shared reference. A complete optical-to-electrical (OE) link is built by integrating the proposed ORX with a high-speed Silicon Photonics (SiP) photodetector (PD). Measurements show that the proposed TIA has a transimpedance gain of 53 dB Ω and a BW of 27 GHz. By integrating it with the SiP PD, the OE front-end (PD+TIA) achieves an input sensitivity of -7.7 dBm at 50 Gb/s and BER ? 2023 IEEE.Accession Number: 20234014841864 -
Record 223 of
Title:Classification of skin cancer based on hyperspectral microscopic imaging and machine learning
Author(s):Qi, Meijie(1,2); Liu, Yujie(1); Li, Yanru(1); Liu, Lixin(1); Zhang, Zhoufeng(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 12601 Issue: null Article Number: 1260103 DOI: 10.1117/12.2666425 Published: 2023Abstract:Hyperspectral microscopic imaging (HMI) technology is a non-contact optical diagnostic method, which combines hyperspectral imaging (HSI) technology with microscopy to provide both spectral information and image information of the samples to be measured. In this paper, basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma (MM) were classified based on synthetic RGB image data from HMI cube by using four classification methods extreme learning machine (ELM), support vector machine (SVM), decision tree and random forest (RF). The highest classification accuracy of 0.791±0.060 and a KAPPA value of 0.685±0.095 were obtained when color moment, gray level co-occurrence matrix (GLCM) and local binary pattern (LBP) were used for image feature extraction, feature dimensions were reduced by the PLS, the sample sets were divided by the hold-out method, and the tissues were classified by the SVM model. ? 2023 SPIE.Accession Number: 20232114125062 -
Record 224 of
Title:Real-Time Self-Calibration Method for SO2 Ultraviolet Cameras
Author(s):Zhang, Zihao(1); Guo, Jianjun(1); Zhang, Huiliang(1); Xiong, Yuanhui(2); Li, Juan(3); Wu, Kuijun(1); He, Weiwei(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 43 Issue: 12 Article Number: 1228005 DOI: 10.3788/AOS221512 Published: June 2023Abstract:Objective The booming shipping industry leads to ever increasing emissions of ship exhaust pollutants. Sulfur dioxide (SO2), the main component of pollutants in ship exhaust, causes the most serious air pollution. Effective monitoring of its emissions is the key to controlling ship exhaust pollution. In recent years, the imaging detection technology of SO2 ultraviolet (UV) cameras has been developed rapidly due to its strong practicability and high reliability and has been applied in ship exhaust monitoring. However, calibration is still the main factor that limits its measurement accuracy and application. There are three calibration methods (calibration cells, DOAS, and spectral calibration) for SO2 UV cameras. The calibration cell method is simple and most employed early in calibration. However, the frequent switching of calibration cells exerts adverse effects on the real-time detection of SO2 UV cameras. Although DOAS is suitable for long-distance monitoring, it has the disadvantages of small field of view (FOV) and poor matching. The accuracy of spectral calibration is significantly improved compared with the first two methods, but the complexity and cost of the camera system are rising with the adoption of an outlay UV spectrometer. With a focus on the self-calibration method, this paper carries out research based on the working mechanism of the SO2 UV camera imaging detection technology, the UV radiation transfer theory, and the simulation of the entire system. Comparison between the advantages of the selfcalibration method and the three traditional calibrations proves that the self-calibration method not only has accurate, simple, and practical technical advantages but also shows its great application prospect in the UV imaging remote sensing monitoring of mobile pollution sources. Methods The signal channel (filter A) is greatly affected by the changing ozone optical path length, but the reference channel (filter B) is relatively less affected. This difference is the source of the basic principle of self-calibration. The theoretical analysis shows that the calibration coefficient is approximately a monotone function of the logarithm of the intensity ratio, and the relationship between them is hardly affected by atmospheric conditions. The inversion process is as follows. First, the signal images of the two channels are obtained through UV cameras. Second, two channels of artificial background images are obtained by the 2-IM method. Before artificial background generation, the dark noise should be deducted from the raw image, and image correlation must be optimized through translation and rotation operations for the best match. Third, the average of the corresponding background intensities of the two channels is employed as the input parameter for self-calibration. The calibration curve of UV cameras can be determined by the logarithmic relationship between the calibration coefficients and the intensity ratio of the two-channel images. The feasibility of the self-calibration method is assessed by the validation experiment. In addition, an outfield experiment is conducted to characterize its accuracy. Results and Discussions The principle for self-calibration is the fact that the two channels of sky background images are affected differently by changes in ozone concentration and the solar zenith angle. The average optical path of solar scattered through the ozone layer increases with the rising solar zenith angle, which makes the ozone absorption worsen the incident light intensity which reaches the cameras system (Fig. 5). As the absorption cross-section of ozone increases significantly towards deep UV wavelength, the signal channel is particularly influenced by variations in ozone optical path length, which is greater than that of the reference channel. Therefore, the functional relationship between the two channels of sky background image intensity ratio and the calibration coefficient can be confirmed (Fig. 7). The validation experiments show that the slope of the calibration curve fitted by the self-calibration method is similar to that obtained by the conventional calibration method with a little difference of about 1. 4% (Fig. 9). In addition, the colormap of the SO2 image of the ship plume retrieved from the UV cameras (Fig. 12) is compared with the data collected by the spectrometer. The results show that the error of the two calibration methods is about 6% (Fig. 13), which demonstrates the feasibility of adopting the self-calibration method to invert the exhaust concentration of movable and low SO2 concentration pollution sources. Conclusions This paper proposes a real-time self-calibration method for UV cameras, with full consideration of the imaging mechanism of UV cameras and UV radiation transfer theory. Regarding the shortcomings of three traditional calibration methods in practical applications, the theoretical basis of the self-calibration method is proposed. The new method can determine calibration curves for retrieving SO2 concentration by employing the intensity ratios of two channels obtained directly from UV cameras. The self-calibration method is compared with the conventional calibration method, and the error is reduced to 1. 4% after filter transmittance correction. To verify the accuracy of the proposed theory, this paper measures the SO2 emission concentration of the ship at Shanghai Port and compares the measurement difference between the self-calibration method and DOAS approach on time series. The error of the two methods is about 6%, which shows good consistency. This study proves that the self-calibration method can overcome the distance limit and adapt to complex environments, with widespread applications in mobile pollution sources. ? 2023 Chinese Optical Society. All rights reserved.Accession Number: 20232914413165 -
Record 225 of
Title:Dual Teacher: A Semisupervised Cotraining Framework for Cross-Domain Ship Detection
Author(s):Zheng, Xiangtao(1,2); Cui, Haowen(3,4); Xu, Chujie(3,4); Lu, Xiaoqiang(1,2)Source: IEEE Transactions on Geoscience and Remote Sensing Volume: 61 Issue: null Article Number: 5613312 DOI: 10.1109/TGRS.2023.3287863 Published: 2023Abstract:Cross-domain ship detection tries to identify synthetic aperture radar (SAR) ships by adapting knowledge from labeled optical images, without labor-intensive annotations. In practical applications, a few (e.g., one or three samples) labeled SAR samples are available, which provides additional supervision for SAR ships. However, the existing cross-domain methods ignore the SAR supervision (a few labeled and unlabeled SAR images), which limits their performances in a practical and under-investigated task: semisupervised cross-domain ship detection (SCSD). In this article, a dual-teacher framework is proposed to address the mutual interference between optical supervision and SAR supervision. First, both optical and SAR supervision are decomposed into two subtasks: cross-domain task and semisupervised task. Then, both cross-domain tasks and semisupervised tasks can be learned interactively in two individual teacher-student models. The teacher-student models generate pseudo-labels on unlabeled SAR images by a teacher network and fine-tune the student network. Finally, the dual-teacher framework retrains two teacher-student models in cotraining strategies. Both cross-domain datasets and semisupervised datasets are exploited to jointly improve the pseudo-label quality. The effectiveness of the dual-teacher framework has been fully experimentally demonstrated. The code is available at https://github.com/XiangtaoZheng/DualTeacher. ? 1980-2012 IEEE.Accession Number: 20232614302412 -
Record 226 of
Title:Design and simulation of space-based photoelectric imaging stabilization control system
Author(s):Cheng, Zhiyuan(1,2); Ji, Zhou(3); Su, Hua(4); Gao, Yansheng(3)Source: ACM International Conference Proceeding Series Volume: null Issue: null Article Number: null DOI: 10.1145/3580219.3580237 Published: January 28, 2023Abstract:Space-based theodolite is an important technology in the field of space remote sensing imaging. The technology can be applied to space optical remote sensing, space astronomical observation, space laser communication and other technical fields. In order to suppress the influence of disturbance of moving satellite platform on the imaging stabilization accuracy and improve the stabilization accuracy of space-based theodolite, a photoelectric imaging stabilization method based on fiber optic gyroscope and Fast Steering Mirror(FSM) was proposed to compensate the disturbance of moving satellite platform. Firstly, fiber optic gyroscope was used to measure the micro-perturbation information of the moving satellite platform. Then the influence of the disturbance on the optical axis direction of the space-based theodolite was compensated by FSM. Finally, the method improved the stability accuracy of the space-based theodolite. A semi-physical simulation experiment platform for space-based photoelectric image stabilization was constructed, and the proposed image stabilization method of space-based theodolite and the space-based stabilization experiment platform was tested and verified. The research results show that the proposed space-based stabilization method can effectively improve the stabilization accuracy of the space-based photoelectric system. The novel stabilization method and space-based stabilization platform can provide effective technical support for the design and development of space high-precision photoelectric stabilization system. ? 2023 Owner/Author.Accession Number: 20231113742172 -
Record 227 of
Title:Research on Driving Technology of Wide Microstrip Amplitude Division Imaging Based on Pulse Power Synthesis Technology
Author(s):Wei, Shiduo(1,2,3); Gou, Yongsheng(1,2,3); Yang, Yang(1,2,3); Feng, Penghui(1,2,3); Liu, Baiyu(1,2,3); Tian, Jinshou(1,2,3); Wang, Xu(1); Liu, Hengbo(1); Xu, Hantao(1,2,3); Yang, Yihao(1,2,3)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 52 Issue: 9 Article Number: 0932002 DOI: 10.3788/gzxb20235209.0932002 Published: September 2023Abstract:When a pulse current with a rise time of about 100 ns and an amplitude of tens of MA is applied to a wire array or jet load，the load will rapidly ionize and form a plasma. Due to the Lorentzian force，these plasms will rapidly implode towards the axis and eventually stagnate in the center，forming a high temperature and high density plasma and further emitting strong X-rays，a process known as Z pinch. Z pinch has been widely used in High Energy Density （HED） physics research for decades，including radiation source development，radiation actuation science，dynamic material properties，Magneto-inertial Fusion（MIF）and Inertial Confinement Fusion（ICF）. In order to explore the structure，properties and motion laws of matter in the ultra-small space and ultra-fast time scale，the research and measurement techniques of ultra-fast phenomena represented by the variometer framing camera technology have become the main tools in use. X-ray framing cameras are widely used for two-dimensional plasma imaging in the Z-pinch process. This type of frame camera requires selective pulses to excite the Microchannel Plate（MCP）. Because the width of the pulse is very narrow，only a microstrip region has voltage at a time，and photoelectrons generated by the X-ray image formed through a pinhole in the region at the input surface of the MCP will be gained and be imaged to the screen on the screen. The exposure time of each image is determined by the half-width of the selected pulse and the characteristics of the framing tube. The MCP with different equivalent impedances will realize the framing camera imaging with different frames. The width and length of the transmission microstrip line of the ultra-wide frame traveling-wave selective framing camera are up to 20 mm and 95 mm，and the equivalent impedance is about 6 Ω. To actuate the beamsplitter，gating pulses with electric field peaks of more than 3 kV，pulse durations on the order of nanoseconds or hundreds of picoseconds，and spectral widths of tens to thousands of megahertz is required. In this paper，the power coupling method based on Wilkinson structure power splitter is adopted to synthesize the narrow-band pulse with low amplitude into the high-voltage pulse with the required amplitude. However，limited by the characteristics of the transistor device itself，the pulse source whose amplitude is higher than 5 kV and the front edge is better than 100 ps and the jitter is better than 20 ps is close to the technical limit of electronics. To obtain higher power gate pulse it is necessary to adopt multichannel pulse power synthesis technology. In this paper，a power coupling method based on Wilkinson structure power splitter is adopted to synthesize the narrow-band pulse with low amplitude into the high-voltage pulse with the required amplitude. The large bandwidth of the multi-section impedance converter is used to improve the working bandwidth of the power coupling，so as to meet the pulse coupling of different spectrum. The simulation software is used to design the power coupling circuit with the working frequency band of 300 MHz~ 3 GHz，and the loss generated in the system is optimized to achieve high efficiency coupling. Combined with the high-voltage narrow pulse output and synchronization control circuit of the preceding stage，the high-voltage pulse with peak voltage exceeding 3.2 kV is synthesized by using eight single-channel pulses with peak voltage of about 1.3 kV and pulse width of about 3.5 ns，pulse leading edge of about 600 ps. The pulse width was within 3 ns and the pulse leading edge was within 600 ps. In the pulse spectrum range of 300 MHz to 3 GHz，the two-channel synthesis efficiency is 83.5%，88% at a specific frequency，and the eight-channel synthesis efficiency is 58%，up to 68% at a specific frequency. Finally，the coupled high-voltage pulse is input into the 20 mm microstrip amplitude-divider. The transmission line of the microchannel plate inside is 20 mm wide and 95 mm long，and the equivalent impedance is 6 Ω. The output pulse amplitude is 1.433 kV，the pulse width is 3.63 ns，and the pulse front is 747.3 ps，which fully conforms to the design requirement that the output voltage of the tube must exceed 800 V. At present，the coupling technique can generate driving pulses for use. In the future，the coupled pulses can be shaped by adjusting the delay of the eight pulses. At present，the high voltage driven pulse source based on this technology has been applied to Ⅰ-MCP1.0 framing camera and can be used to explore the high energy density physics research with Z-pinch as the core. ? 2023 Chinese Optical Society. All rights reserved.Accession Number: 20234014834323 -
Record 228 of
Title:Ophthalmic fundus camera design based on freeform surface for reducing refractive error sensitivity
Author(s):Zhang, Wenchao(1); Chen, Weilin(1); Chang, Jun(1); Huang, Yi(1); Zhao, Xuehui(1); Li, Xuyang(2)Source: Optics and Lasers in Engineering Volume: 169 Issue: null Article Number: 107714 DOI: 10.1016/j.optlaseng.2023.107714 Published: October 2023Abstract:The eye has a remarkably complex structure and biomechanics. An imbalance between the forces acting on several muscles and the tissue properties may alter or even preclude vision. With the widespread use of electronics, refractive errors have become a common problem, making clear fundus imaging difficult. To overcome this challenge, freeform surfaces have emerged as a potential solution, enabling compact, low-cost, and user-friendly systems that are insensitive to refractive errors. We propose a fundus camera based on a freeform surface that can image the fundus without the influence of refractive errors. A special front lens was designed to image the pupil on a freeform lens that can realize phase modulation. The system performs well providing a field of view of 40° and a pupil diameter of 3 mm for refractive errors ranging from -5D to +5D. The volume of the system was less than 35 mm × 35 mm × 135 mm. ? 2023Accession Number: 20232814380860