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Record 1 of
Title:Research on Underwater Navigation and Positioning Method Based on Sea Surface Buoys and Undersea Beacons
Author(s):Zhai, Wei(1); Wu, Jiali(2); Chen, Yaru(1); Jing, Zengzeng(1); Sun, Guang(1); Hong, Yingjie(1); Fan, Yi(1); Fan, Shunxi(1)
Source: Lecture Notes in Electrical Engineering Volume: 652 LNEE Issue: DOI: 10.1007/978-981-15-3715-8_36 Published: 2020
Abstract:When underwater vehicles and underwater robots are used for underwater tasks such as resource sampling, environmental exploration and wreck salvage, the positioning system is capable of reflecting the location information in a timely and accurate manner. Traditional underwater navigation and positioning is based on inertial navigation, assisted by surface satellite signals to achieve positioning information feedback, which requires frequent surface alignment, which increases the safety risk of underwater vehicle and reduces work efficiency. By setting up an underwater beacon array, establishing high-precision marine surveying datum, and utilizing the principle of underwater acoustic positioning, the precise navigation and positioning of underwater vehicle can be realized. This makes up for the deficiency of inertial navigation systems and improves the safety and working efficiency of underwater vehicle. In this research, a set of underwater stereo high-precision positioning system was built by integrating technologies including beacon transponder reference position calibration, sound ray bending ranging error correction, the high-precision positioning of long baseline underwater vehicles. The system built was tested in the Yangtze River with semi-physical simulation experiment. Feasibility and efficiency of the proposed methodology related to underwater navigation beacon array was successfully validated. ? 2020, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Accession Number: 20202408822723
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Record 2 of
Title:Deep Learning for Three Types of Keratitis Classification based on Confocal Microscopy Images
Author(s):Zhang, Xinming(1,2); Ding, Gang(3); Gao, Chi(1,2); Li, Chao(1,2); Hu, Bingliang(1); Zhang, Chenming(3); Wang, Quan(1)
Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/3432291.3432310 Published: October 22, 2020
Abstract:Accurate diagnosis of keratitis is important for the follow up treatment. The confocal microscope can scan different depth and layer of the cornea, therefore is an important tool for clinical diagnosis of keratitis. We collected, augmented and preprocessed the confocal microscopic images. In this paper, three kinds of infectious keratitis samples including viral keratitis, bacterial keratitis, and fungal keratitis were classified with ResNet (Residual Network). The results show that the recognition rate of three kinds of keratitis can reach 91.82%, and the accuracy rate of single keratitis could reach 99.09%. In addition, cross-validation was performed on each patient in the dataset. The classification accuracy rate reached 75.00%). This work extended the previous work of identifying fungal keratitis only to three categories and reach a good classification rate of keratitis. ? 2020 ACM.
Accession Number: 20205209687182
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Record 3 of
Title:Research on photoelectric signal preprocessing of four-quadrant detector in free space optical communication system
Author(s):Wang, Xuan(1,2,3); Su, Xiuqin(1); Liu, Guizhong(2); Han, Junfeng(1); Wang, Rui(1,3)
Source: 2020 IEEE 5th International Conference on Signal and Image Processing, ICSIP 2020 Volume: Issue: DOI: 10.1109/ICSIP49896.2020.9339342 Published: October 23, 2020
Abstract:In the free space optical communication system, the detection accuracy and detection speed of the beam deflection angle have an important influence on the tracking accuracy and tracking speed of the precision tracking system. The beam deflection angle is equivalent to the position detection of the laser spot on the photo-sensitive surface of the precision tracking detector. Using a four-quadrant detector to detect the spot position error in real time can effectively eliminate the spot jitter error through the correction mechanism. By analyzing the signal characteristics of the four-quadrant detector, a photoelectric signal preprocessing circuit for the four-quadrant detector output is designed and implemented. Including the transimpedance amplifier module, low-pass filter module, main amplification module. Finally, the spot position is calculated by the photocurrent in the four quadrants. Through theoretical calculation, physical modeling, simulation, the designed signal preprocessing circuit is verified by simulation. The simulation results show that the magnification of designed signal preprocessing circuit is 2×108 and the bandwidth is 1.97MHz, which can provide a strong guarantee for the calculation of the spot position of the four-quadrant detector. ? 2020 IEEE.
Accession Number: 20210809970629
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Record 4 of
Title:Sparse spectral signal reconstruction for one proposed nine-band multispectral imaging system
Author(s):Sun, Bangyong(1,3); Zhao, Zhe(1); Xie, Dehong(2); Yuan, Nianzeng(1); Yu, Zhe(1); Chen, Fuwei(1); Cao, Congjun(1); de Dravo, Vincent Whannou(1)
Source: Mechanical Systems and Signal Processing Volume: 141 Issue: DOI: 10.1016/j.ymssp.2020.106627 Published: July 2020
Abstract:Multispectral filter array (MSFA) imaging with one single sensor is a portable and inexpensive means of acquiring spectral image which is widely used for object detection, material analysis and mechanical system diagnosis. The most challenging task for MSFA imaging is the multispectral demosaicking with the aim of reconstructing the captured raw/mosaic image, especially for the systems with many bands which result in higher sparseness of the raw data. In this paper, we present a 9-band MSFA imaging system in a repetitive 4 × 4 filter array on a single sensor, and propose a demosaicking algorithm for reconstructing the raw spectral image. Within the 4 × 4 MSFA pattern, the fifth spectral band takes up half of the total spatial position while the remaining eight bands occupy 1/16 respectively. To reconstruct the sparse raw data, we first recover the fifth band by propagating the neighboring sampled pixels to the unsampled position using the image gradients, and then employ the reconstructed fifth band as a guided image to demosaick the other bands with the guided filter and residual interpolation. Finally, we estimate the spectral reflectance values from the multispectral image and the characterization matrix. In the experiment, we evaluate the performance of the 9-band imaging system with the binary tree-based edge-sensing (BTES) algorithm, compressed sensing (CS) algorithm, and our proposed demosaicking algorithm. The experiment results demonstrate that our demosaicking algorithm not only outperforms BTES and CS algorithms in terms of objective image quality, e.g., PSNR values and spectral errors, but also reduces the demosaicking artifacts in terms of subjective evaluations. ? 2020 Elsevier Ltd
Accession Number: 20200608123648
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Record 5 of
Title:Broadband Microwave Frequency Conversion Based on an Integrated Optical Micro-Comb Source
Author(s):Xu, Xingyuan(1); Wu, Jiayang(1); Tan, Mengxi(1); Nguyen, Thach G.(2); Chu, Sai T.(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)
Source: Journal of Lightwave Technology Volume: 38 Issue: 2 DOI: 10.1109/JLT.2019.2930466 Published: January 15, 2020
Abstract:We report a broadband microwave frequency converter based on a coherent Kerr optical micro-comb generated by an integrated micro-ring resonator. The coherent micro-comb displays features that are consistent with soliton crystal dynamics with a free spectral range of 48.9 GHz. We use this to demonstrate a high-performance millimeter-wave local oscillator for microwave frequency conversion. We experimentally verify the microwave performance up to 40 GHz, achieving a ratio of-6.8 dB between output radio frequency power and intermediate frequency power and a spurious suppression ratio of >43.5 dB. The experimental results show good agreement with theory and verify the effectiveness of microwave frequency converters based on coherent optical micro-combs, with the ability to achieve reduced size, complexity, and potential cost. ? 1983-2012 IEEE.
Accession Number: 20200508114891
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Record 6 of
Title:Pointing design and testing of corner reflector
Author(s):Liu, Jie(1); Wang, Hu(1,2); Lin, Shangmin(3); Xue, Yaoke(1); Liu, Yang(1); Liu, Meiying(1); Shen, Yang(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2580209 Published: 2020
Abstract:The corner reflector is usually realized by fixing the corner cube prism through a specific structure, which is much easier to install and debugin practical application. As we all know, one of the most important uses of the corner reflector is that it can be used as a passive target marker for satellites and aircrafts. At a certain distance, as the angle of incidence increases, the return light efficiency of the corner reflector gradually decreases, and the return light efficiency directly affects the shape and brightness of the target point. Usually when multiple targets are tracked, the better the target direction consistency, the more uniform the light spot can be obtained. This paper introduces the method of drawing the normal direction of the corner cube prism to the mounting surface. The normal direction of the corner cube prism is tested by the self-collimating theodolite and the direction error is within 1, and the error of return light efficiency is better than 5%, which provides high-precision pointing for the combination of multiple corner reflectors. On this basis, we expand the pointing design of the sub-corner cube prism for the plane array of the corner reflectors. After testing, the direction error of the sub-corner cube prism is within 5. ? 2020 SPIE.
Accession Number: 20205009602455
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Record 7 of
Title:Generalized polarimetric dehazing method based on low-pass filtering in frequency domain
Author(s):Liang, Jian(1,2); Ju, Haijuan(1); Ren, Liyong(3); Yang, Liming(1); Liang, Rongguang(2)
Source: Sensors (Switzerland) Volume: 20 Issue: 6 DOI: 10.3390/s20061729 Published: March 2020
Abstract:Polarimetric dehazing methods can significantly enhance the quality of hazy images. However, current methods are not robust enough under different imaging conditions. In this paper, we propose a generalized polarimetric dehazing method based on low-pass filtering in the frequency domain. This method can accurately estimate the polarized state of the scattering light automatically without adjusting bias parameters. Experimental results show the effectiveness and robustness of our proposed method in different hazy weather and scattering underwater environments with different densities. Furthermore, computational efficiency is enhanced more than 70% compared to the polarimetric dehazing method we proposed previously. ? 2020 by the authors. Licensee MDPI, Basel, Switzerland.
Accession Number: 20201308357451
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Record 8 of
Title:Research on the calibration technique of the low-light-level remote sensing camera
Author(s):Bai, Zhe(1); Ma, Yilong(1); Pan, Yue(1); Pang, Zhihai(1); Zhao, Hui(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2580218 Published: 2020
Abstract:In recent years, Low-Light-Level (LLL) remote -sensing camera has become a novel subject for the development of aerospace optical remote-sensing payloads. LLL remote sensing camera works in ultra-low light conditions, the image signal is very weak and requires image intensified technology to achieve. In order to make better use of LLL remote sensing data, it is necessary to establish the quantitative relationship between the amount of radiation received by the camera and the digital signal output to process the image. That's radiation calibration technology. Therefore, the radiation calibration of the LLL remote sensing camera is particularly important. In this article, first the requirements for calibration of LLL remote sensing cameras are analyzed in theory. After that, a radiation calibration scheme of the LLL remote sensing camera is put forward. Finally, the radiation calibration test is carried out, and the calibration data are analyzed. The results show that the calibration scheme of LLL remote sensing camera is reasonable and feasible. ? 2020 SPIE.
Accession Number: 20205009602457
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Record 9 of
Title:Hemoglobin Detection Based on Excessively Tilted Fiber Grating by Non-covalent bonding
Author(s):Sun, Yuezhen(1); Lu, Tean(1); Wang, Hushan(2); Sun, Qizhen(1); Yan, Zhijun(1); Liu, Deming(1)
Source: 2020 Asia Communications and Photonics Conference, ACP 2020 and International Conference on Information Photonics and Optical Communications, IPOC 2020 - Proceedings Volume: Issue: DOI: null Published: October 2020
Abstract:We have demonstrated a novel hemoglobin sensor based on hydroxide bond functionalized excessively tilted fiber grating. Due to non-covalent bonding between hydroxide bond and hemoglobin, such sensor could achieve hemoglobin detection with sensitivity around 1.93nm/(mg/ml). ? 2020 The Author(s)
Accession Number: 20211210116490
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Record 10 of
Title:Coherent synthetic aperture imaging for visible remote sensing via reflective Fourier ptychography
Author(s):Xiang, Meng(1,2); Pan, An(1,2); Zhao, Yiyi(1); Fan, Xuewu(1); Zhao, Hui(1); Li, Chuang(1); Yao, Baoli(1)
Source: arXiv Volume: Issue: DOI: null Published: August 1, 2020
Abstract:Synthetic aperture radar (SAR) can measure the phase with antenna and microwave, which cannot be directly extended to visible light imaging due to phase lost. In this letter, we reported an active remote sensing with visible light via reflective Fourier ptychography (FP), termed coherent synthetic aperture imaging (CSAI), achieving high resolution, wide field-of-view (FOV) and phase recovery. A proof-of-concept experiment was reported with laser scanning and a collimator for the infinite object. Both smooth and rough objects are tested, and the spatial resolution increased from 15.6 μm to 3.48 μm with a factor of 4.5. The speckle noise can be suppressed by FP unexpectedly. Meanwhile, the CSAI method may replace the adaptive optics to tackle the aberration induced from atmospheric turbulence and optical system by one-step deconvolution. Copyright ? 2020, The Authors. All rights reserved.
Accession Number: 20200581308
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Record 11 of
Title:Data Association Based Fast Fault Detection for Low-Cost Micro/Nano-Satellite
Author(s):Chen, Rongli(1); Wang, Xiaodong(2); Guo, Yangming(2); Qin, Weihua(3); Zhang, Ximing(1)
Source: Proceedings of 2020 International Conference on Sensing, Diagnostics, Prognostics, and Control, SDPC 2020 Volume: Issue: DOI: 10.1109/SDPC49476.2020.9353167 Published: August 5, 2020
Abstract:Under most circumstances, it is very important to achieve fast and real-Time low-cost micro/nano-satellite fault detection. Regarding of faults as dynamic modes which observe through the multi-sensors, with probabilistic data association based on multi-sensor, we obtain the fault detection results according to the association probability and the threshold values. Joint Probabilistic Data Association (JPDA) algorithm is one of the effective ways for multi-sensor and multi-Target tracking. We improve the JPDA algorithm as follows: At first, we propose an approximation method for constructing the confirmation matrix by removing the small probability events using the right threshold, and then, we present the mathematical division of the confirmation matrix according to the intersection area of the association gate of fault targets to be tracked; Finally, we compute the association probability of fault targets through attenuating the value of the public measurement. The simulation results show preliminarily that our improved JPDA algorithm saves the computational time greatly, and meet the requirements of fast and real-Time fault detection effectively. ? 2020 IEEE.
Accession Number: 20211010056176
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Record 12 of
Title:End-to-end learning interpolation for object tracking in low frame-rate video
Author(s):Liu, Liqiang(1,2); Cao, Jianzhong(1)
Source: IET Image Processing Volume: 14 Issue: 6 DOI: 10.1049/iet-ipr.2019.0944 Published: May 11, 2020
Abstract:In many scenarios, where videos are transmitted through bandwidth-limited channels for subsequent semantic analytics, the choice of frame rates has to balance between bandwidth constraints and analytics performance. Faced with this practical challenge, this study focuses on enhancing object tracking at low frame rates and proposes a learning Interpolation for tracking framework. This framework embeds an implicit video frame interpolation sub-network, which is concatenated and jointly trained with another object tracking sub-network. Once a low frame-rate video is an input, it is first mapped into a high frame-rate latent video, based on which the tracker is learned. Novel strategies and loss functions are derived to ensure the effective end-to-end optimisation of the authors' network. On several challenging benchmarks and settings, their method achieves a highly competitive tradeoff between frame rate and tracking accuracy. As is known, the implications of interpolation on semantic video analytics and tracking remain unexplored, and the authors expect their method to find many applications in mobile embedded vision, Internet of Things and edge computing. ? The Institution of Engineering and Technology 2020
Accession Number: 20201908616093
