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Record 253 of
Title:An anomaly detection algorithm for hyperspectral imagery based on graph laplacian
Author(s):Gan, Yuquan(1,2); Liu, Ying(1,2); Yang, Fanchao(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11566 Issue: DOI: 10.1117/12.2575009 Published: 2020Abstract:Traditional anomaly detection algorithms for hyperspectral imagery does not consider spatial information of imagery, which decreases detection efficiency of anomaly detection. The traditional RXD algorithm uses Gauss model to evaluate the distribution of background, but ignores spatial correlation of the imagery. Aiming at improving detection efficiency, this paper proposed an anomaly detection algorithm which utilize both spatial and spectral information of hyperspectral imagery based on graph Laplacian. In this paper, an anomaly detection algorithm for hyperspectral imagery based on graph Laplacian (Graph Laplacian Anomaly Detection with Mahalanobis distance, LADM) is presented. The spatial information is considered in the model by graph Laplacian matrix. First, LADM considers not only spectral information but also the spatial information by mapping image to a graph. Secondly, a symmetrical normalization Laplacian matrix is constructed for the graph with Mahalanobis distance. The operation eliminates interference among the nodes, which improves the accuracy of Laplacian matrix and improves the detection result. Thirdly, LADM detectors is constructed with graph Laplacian detection model. Lastly, anomaly detection model based on graph is given based on graph Laplacian and spectral vector of the pixels. A threshold value is given to judge whether the currently detection pixel is anomaly or not. Experiments for synthetic data and real hyperspectral image is proposed in this paper. The proposed algorithm is compared with three classical anomaly detection algorithms. ROC curves and AUC values are given for both synthetic data and real data in the paper. Experiments results show that LADM algorithm can improve the accuracy of anomaly detection for hyperspectral imagery, and reduced the false alarm rate. ? 2020 SPIE. All rights reserved.Accession Number: 20204909589274 -
Record 254 of
Title:Quantum Key Distribution with On-Chip Dissipative Kerr Soliton
Author(s):Wang, Fang-Xiang(1,3,5); Wang, Weiqiang(2,4); Niu, Rui(1,3); Wang, Xinyu(2,4); Zou, Chang-Ling(1,3); Dong, Chun-Hua(1,3); Little, Brent E.(2); Chu, Sai T.(6); Liu, Hang(1,3,5); Hao, Penglei(7); Liu, Shufeng(7); Wang, Shuang(1,3,5); Yin, Zhen-Qiang(1,3,5); He, De-Yong(1,3,5); Zhang, Wenfu(2,4); Zhao, Wei(2,4); Han, Zheng-Fu(1,3,5); Guo, Guang-Can(1,3,5); Chen, Wei(1,3,5)Source: Laser and Photonics Reviews Volume: 14 Issue: 2 DOI: 10.1002/lpor.201900190 Published: February 1, 2020Abstract:Quantum key distribution (QKD) can distribute symmetric key bits between remote legitimate users with the guarantee of quantum mechanics principles. For practical applications, there is increasing attention to integrating the source, detectors, and modulators on a photonic chip. Here, the Kerr dissipative soliton is introduced in a microresonator as the light source for GHz QKD systems, and the proof-of-principle experiment demonstrates the parallel QKD can be achieved using coherent comb lines from the soliton. The performance of parallel QKD is also verified by using the off-the-shelf wavelength division modules and the on-chip soliton source. Since the on-chip soliton can provide hundreds of carriers covering the C and L bands, the results exhibit the feasibility to achieve ultra-high rate secure key bits through massively parallel QKD, especially when incorporated with the thriving photonic integrated circuit?technology. ? 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimAccession Number: 20200408070441 -
Record 255 of
Title:The Visible Telescope onboard the Chinese-French SVOM satellite
Author(s):Fan, Xuewu(1); Zou, Gangyi(1,2); Wei, Jianyan(3); Qiu, Yulei(3); Gao, Wei(1); Wang, Wei(1); Yang, Wengang(1); Zhang, Jian(1); Li, Chuang(1); Zhao, Hui(1); Dan, Lijun(1); Song, Zongxi(1); Feng, Liangjie(1); Ren, Guorui(1); Huang, Chao(1); Yuan, Hao(1); Sun, Zhonghan(1); Wang, Fengtao(1); Wang, Chenjie(1); Li, Wei(1); Shen, Chao(1); Qi, Ning(1); Pan, Yue(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11443 Issue: DOI: 10.1117/12.2561854 Published: 2020Abstract:The Space-based multi-band astronomical Variable Objects Monitor (SVOM) project is a dedicated satellite developed at the cooperation of China and France, aim to make prompt multi-band observations of Gamma-Ray Bursts (GRBs), the afterglows and other high-energy transient astronomical events. The Visible Telescope (VT) is one of the four payloads onboard the SVOM. VT is designed to observe the afterglows of GRBs both in the visible and near infrared bands simultaneously. The telescope can reach a limiting magnitude of +22.5Mv and provide the redshift indicators for high-Z (z ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20210509847798 -
Record 256 of
Title:Fully noncontact measurement of inner cracks in thick specimen with fiber-phased-array laser ultrasonic technique
Author(s):Pei, Cuixiang(1,2); Yi, Dongchi(1,3); Liu, Tianhao(1); Kou, Xing(1); Chen, Zhenmao(1)Source: NDT and E International Volume: 113 Issue: DOI: 10.1016/j.ndteint.2020.102273 Published: July 2020Abstract:To realize a fully noncontact ultrasonic testing method for inner cracks inspection in thick metal specimen, a phased array laser ultrasonic testing system with using a compact optic fiber array bundle and a laser interferometer is developed in this study. The focusing and steering of the shear wave and longitudinal wave generated with seven fiber-phased-array laser sources in thermoelastic regime is investigated by a numerical simulation and validated by the experiment. A non-contact measurement of the inner-surface cracks by both the angle-beam testing method and time-of-flight diffraction method with the fiber-phased-array laser ultrasonic technique have been studied. ? 2020 Elsevier LtdAccession Number: 20201708534628 -
Record 257 of
Title:Femtosecond laser-induced non-centrosymmetric surface microstructures on bulk metallic glass for unidirectional droplet micro-displacement
Author(s):Li, Chen(1); Yang, Lijun(1); Ren, Xuezhuang(1); Yang, Yong(2); Cheng, Guanghua(3)Source: Journal of Physics D: Applied Physics Volume: 53 Issue: 10 DOI: 10.1088/1361-6463/ab5df7 Published: 2020Abstract:Unidirectional droplet motion without energy input has attracted considerable attention in various potential applications. We report on the fabrication of unconventional laser-induced periodic surface structures (LIPSS) for unidirectional droplet micro-displacement by a femtosecond laser at a large incident angle. In order to overcome the mechanical durability of the existing soft materials such as PDMS for controlling the droplet, Zr-based bulk metallic glass (Zr-BMG) is used to fabricate the typical non-centrosymmetric unconventional LIPSS, which include micro-sized elliptical arc-shaped structures and nano-ripples with the central spatial periodicity of 400 nm. The spots and the grating of unconventional LIPSS on Zr-BMG are fabricated to construct the functional surface structures by femtosecond laser irradiation. The unidirectional micro-displacement of water droplet on Zr-BMG was achieved using functional surface structures. For better understanding the fabrication of unconventional LIPSS, the underlying formation mechanism was revealed by numerical simulations. This work gives a fast, precise and low-cost method to fabricate the non-centrosymmetric surface micro/nano-structures on metal materials for unidirectional droplet motion in microfluidics. ? 2019 IOP Publishing Ltd.Accession Number: 20200808197165 -
Record 258 of
Title:Accurate volume measurement of road potholes based on 3d point clouds
Author(s):Xu, Mingming(1,2); Zhou, Zuofeng(1); Wu, Qingquan(3); Huang, Huimin(1,2); Du, Ying(1,2); Cao, Jianzhong(1); Hu, Guoliang(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11519 Issue: DOI: 10.1117/12.2573129 Published: 2020Abstract:In the daily driving process, road potholes pose a great threat to traffic safety. However, the actual road potholes are often irregular and the background is complex. So, it is difficult to accurately measure the volume of potholes. In this paper, a method for measuring the volume of road potholes based on three-dimensional point clouds is presented. First, binocular vision is used to obtain 3D point cloud data of the pothole, and the segmented pothole point clouds are projected onto the coordinate plane established by the road surface. Then, we triangulate projection points on the coordinate plane. Finally, restore these points to the true elevation points to generate triangular prism, and calculate the volume of a single triangular prism one by one. The accuracy and effectiveness of this algorithm are verified by experiments. ? 2020 SPIE.Accession Number: 20202908951772 -
Record 259 of
Title:Sound Active Attention Framework for Remote Sensing Image Captioning
Author(s):Lu, Xiaoqiang(1); Wang, Binqiang(1,2); Zheng, Xiangtao(1)Source: IEEE Transactions on Geoscience and Remote Sensing Volume: 58 Issue: 3 DOI: 10.1109/TGRS.2019.2951636 Published: March 2020Abstract:Attention mechanism-based image captioning methods have achieved good results in the remote sensing field, but are driven by tagged sentences, which is called passive attention. However, different observers may give different levels of attention to the same image. The attention of observers during testing, then, may not be consistent with the attention during training. As a direct and natural human-machine interaction, speech is much faster than typing sentences. Sound can represent the attention of different observers. This is called active attention. Active attention can be more targeted to describe the image; for example, in disaster assessments, the situation can be obtained quickly and the corresponding disaster areas can be located related to the specific disaster. A novel sound active attention framework is proposed for more specific caption generation according to the interest of the observer. First, sound is modeled by mel-frequency cepstral coefficients (MFCCs) and the image is encoded by convolutional neural networks (CNNs). Then, to handle the continuity characteristic of sound, a sound module and an attention module are designed based on the gated recurrent units (GRUs). Finally, the sound-guided image feature processed by the attention module is imported into the output module to generate descriptive sentence. Experiments based on both fake and real sound data sets show that the proposed method can generate sentences that can capture the focus of human. ? 1980-2012 IEEE.Accession Number: 20201008273153 -
Record 260 of
Title:Approximate Reliability Analysis for New Generation Avionics Network
Author(s):Guo, Lin(1,2); Wang, Xiaodong(1,3); Wang, Zhuqing(1); Zhang, Shuang(4); Guo, Yangming(1)Source: 2020 Asia-Pacific International Symposium on Advanced Reliability and Maintenance Modeling, APARM 2020 Volume: Issue: DOI: 10.1109/APARM49247.2020.9209403 Published: August 2020Abstract:The new generation avionics network consists of various topologies including point-to-point, arbitrated loop and switched structures. The precise reliability computation of such a large-scale network seems to be an NP-hard problem. According to the reliability analysis and feature of avionic networks, this paper proposed three reliability computation models via topological transformations which are the possible connecting cases of equipment and links in the avionics networks. The proposed models can be applied to compute the reliabilities of point-to-point and arbitrated loop topologies structures precisely, and also the probability of switched topology structure approximately through determining the upper bound. While the approximate reliability calculation process of the avionics system network can be conducted by combining the proposed models for different sub-structures three models. Finally, the approximate reliability analysis of a certain avionic network example is performed with the corresponding result being provided, and then the rules of approximate reliability computing are also indicated. ? 2020 IEEE.Accession Number: 20204409413303 -
Record 261 of
Title:A pothole detection method based on 3d point cloud segmentation
Author(s):Du, Ying(1,2); Zhou, Zuofeng(1); Wu, Qingquan(3); Huang, Huimin(1,2); Xu, Mingming(1,2); Cao, Jianzhong(1); Hu, Guoliang(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11519 Issue: DOI: 10.1117/12.2573124 Published: 2020Abstract:Road potholes affect comfort, safety, traffic condition and vehicle stability. Accurately detecting these potholes is vital for assessing the degree of pavement distress and developing road maintenance plan accordingly. This paper proposes a simple and effective pothole detection method based on 3D point cloud segmentation. Using binocular stereo vision to acquire 3D point clouds, fitting the pavement plane and then eliminating it from the 3D point clouds of road scene, we could roughly extract the pothole. K-means clustering and region growing algorithms were adopted to extract the potholes precisely. The experimental results demonstrate that our proposed method has a very good segmentation effect on scenes involving plane and target object. ? 2020 SPIE.Accession Number: 20202908951807 -
Record 262 of
Title:Design of a novel high-performance ultrafast optical framing camera
Author(s):Lei, X.(1); Cai, C.(2); Zhang, M.(2); Wu, S.(1); Wang, J.(2); Tian, J.(2); Lu, Y.(2); Wen, W.(2); Pei, C.(3,4); Liu, A.(2)Source: Journal of Instrumentation Volume: 15 Issue: 3 DOI: 10.1088/1748-0221/15/03/P03007 Published: March 2020Abstract:The analysis of fast physical phenomena is a relevant tool in several fields including atomic physics and photochemistry. In turn, to record phenomena occurring on an ultra-short time scale, one needs an imaging system that can accurately capture the event. In this paper, we propose a novel ultrafast optical framing camera that achieves a spatial resolution up to 36.6 LP/mm while keeping a high temporal resolution of 3.25 ns using a digital delay generator. Our technique involves the splitting of light into four beams and their imaging on four ICCD cameras. In addition, the data transfer system is designed to combine data-streams from multiple digital ports into a single output, thus providing a compact user interface. The characteristic parameters influencing the temporal resolution of the image intensifier has been analyzed, and the framing camera has been experimentally assessed. Our results show that a temporal resolution of 3.25 ns and a spatial resolution of 36.6 LP/mm can be obtained. We foresee the use of our apparatus for inertial confined fusion. ? 2020 IOP Publishing Ltd and Sissa Medialab.Accession Number: 20202108677201 -
Record 263 of
Title:Design and Simulation of an Intelligent Current Monitoring System for Urban Rail Transit
Author(s):Yao, Cheng(1); Zhao, Qinglei(2); Ma, Zelong(2); Zhou, Wei(2); Yao, Tong(3)Source: IEEE Access Volume: 8 Issue: DOI: 10.1109/ACCESS.2020.2975009 Published: 2020Abstract:Many urban rail transit (URT) systems adopt the DC traction power supply system. Because of the impedance and incomplete ground insulation of the running track, it is inevitable for a part of the traction current to flow into the ground from the track, creating the stray current. This type of current causes great safety hazards to the metal structures in and near the URT system. Considering the power supply mode of the URT, this paper explores the different resistances in each power supply section under unilateral power supply and bilateral power supply. Then, the defects of the current discharge method were identified in the context of stray current protection. To solve these defects, the backpropagation neural network (BPNN) was adopted to build a discharge flow prediction model. On this basis, an intelligent current monitoring system was established for the URT. Finally, the authors simulated the impact of each factor on stray current, and verified the reliability and stability of the proposed monitoring system. Compared with predicted values and the actual values, the prediction agrees with the actual data very well. ? 2013 IEEE.Accession Number: 20201008273531 -
Record 264 of
Title:Design of infrared dual-band/dual-FOV imaging early warning system
Author(s):Zhang, Hong-Wei(1,2,3); Ding, Ya-Lin(1); Ma, Ying-Jun(3); Chen, Wei-Ning(3)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 28 Issue: 6 DOI: 10.3788/OPE.20202806.1283 Published: June 1, 2020Abstract:To address the demand for detection of point/dim targets in complex environments, an infrared dual-band dual-field of view (FOV) imaging early warning system was designed. To improve the target detection capability and environmental adaptability, the system used high-order aspheric surfaces to reduce the number of system lenses and improve the system transmittance. At the same time, it corrects on-axis/off-axis aberrations and advanced aberrations to improve the imaging quality of the system. An optical passive compensation method was adopted to realize an athermalized design in the range of -40℃ to 60℃. A rotating electromagnet was used as the driving element to complete the zooming in process in a duration of 80 ms to ensure that the target is not lost during the FOV switching process. Using the electric limit, mechanical limit, and magnetic locking mechanism as limit components, the stabilization accuracy of the optical axis wobble is less than two pixels. The design results show that the optical-mechanical structure of the infrared imaging early warning system is reasonable and compact, the imaging quality is good, and it meets the requirements of target detection. The system has potential application prospects in the field of infrared imaging in early warning systems. ? 2020, Science Press. All right reserved.Accession Number: 20202608879521