2014
2014
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Record 61 of
Title:Dayside aurora classification via BIFs-based sparse representation using manifold learning
Author(s):Han, Bing(1,2); Zhao, Xiaojing(1,2); Tao, Dacheng(3); Li, Xuelong(4); Hu, Zejun(5); Hu, Hongqiao(5)Source: International Journal of Computer Mathematics Volume: 91 Issue: 11 DOI: 10.1080/00207160.2013.831084 Published: November 2, 2014Abstract:Aurora is the typical ionosphere track generated by the interaction of solar wind and magnetosphere, whose modality and variation are significant to the study of space weather activity A new aurora classification algorithm based on biologically inspired features (BIFs) and discriminative locality alignment (DLA) is proposed in this paper First, an aurora image is represented by the BIFs, which combines the C1 units from the hierarchical model of object recognition in cortex and the gist features from the saliency map; then, the manifold learning method called DLA is used to obtain the effective sparse representation for auroras based on BIFs; finally, classification results using support vector machine and nearest neighbour with three sets of features: the C1 unit features, the gist features and the BIFs illustrate the effectiveness and robustness of our method on the real aurora image database from Chinese Arctic Yellow River Station. ? 2013, Taylor & Francis.Accession Number: 20144900275326 -
Record 62 of
Title:The high energy cosmic-radiation detection (HERD) facility onboard China's Space Station
Author(s):Zhang, S.N.(1); Adriani, O.(2); Albergo, S.(2); Ambrosi, G.(2); An, Q.(3); Bao, T.W.(1); Battiston, R.(4); Bi, X.J.(1); Cao, Z.(1); Chai, J.Y.(1); Chang, J.(5); Chen, G.M.(1); Chen, Y.(6); Cui, X.H.(7); Dai, Z.G.(6); D'Alessandro, R.(2); Dong, Y.W.(1); Fan, Y.Z.(5); Feng, C.Q.(3); Feng, H.(8); Feng, Z.Y.(1); Gao, X.H.(9); Gargano, F.(2); Giglietto, N.(2); Gou, Q.B.(1); Guo, Y.Q.(1); Hu, B.L.(9); Hu, H.B.(1); He, H.H.(1); Huang, G.S.(3); Huang, J.(1); Huang, Y.F.(6); Li, H.(1); Li, L.(1); Li, Y.G.(1); Li, Z.(10); Liang, E.W.(11); Liu, H.(1); Liu, J.B.(3); Liu, J.T.(1); Liu, S.B.(3); Liu, S.M.(5); Liu, X.(1); Lu, J.G.(1); Mazziotta, M.N.(2); Mori, N.(2); Orsi, S.(12); Pearce, M.(13); Pohl, M.(14); Quan, Z.(1); Ryde, F.(13); Shi, H.L.(1); Spillantini, P.(2); Su, M.(15); Sun, J.C.(1); Sun, X.L.(1); Tang, Z.C.(1); Walter, R.(12); Wang, J.C.(16); Wang, J.M.(1); Wang, L.(9); Wang, R.J.(1); Wang, X.L.(3); Wang, X.Y.(6); Wang, Z.G.(24); Wei, D.M.(5); Wu, B.B.(1); Wu, J.(17); Wu, X.(12); Wu, X.F.(5); Xia, J.Q.(1); Xiao, H.L.(22); Xu, H.H.(1); Xu, M.(23); Xu, Z.Z.(3); Yan, H.R.(10); Yin, P.F.(1); Yu, Y.W.(18); Yuan, Q.(1); Zha, M.(1); Zhang, L.(19); Zhang, L.(20); Zhang, L.Y.(1); Zhang, Y.(21); Zhang, Y.J.(1); Zhang, Y.L.(3); Zhao, Z.G.(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9144 Issue: DOI: 10.1117/12.2055280 Published: 2014Abstract:The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads of the cosmic lighthouse program onboard China's Space Station, which is planned for operation starting around 2020 for about 10 years. The main scientific objectives of HERD are indirect dark matter search, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 104 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of seven X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side SKTs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV, 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R and D is under way for reading out the LYSO signals with optical fiber coupled to image intensified CCD and the prototype of one layer of CALO. ? 2014 SPIE.Accession Number: 20150700523490 -
Record 63 of
Title:Spectral-spatial constraint hyperspectral image classification
Author(s):Ji, Rongrong(1); Gao, Yue(2); Hong, Richang(3); Liu, Qiong(4); Tao, Dacheng(5); Li, Xuelong(6)Source: IEEE Transactions on Geoscience and Remote Sensing Volume: 52 Issue: 3 DOI: 10.1109/TGRS.2013.2255297 Published: March 2014Abstract:Hyperspectral image classification has attracted extensive research efforts in the recent decade. The main difficulty lies in the few labeled samples versus the high dimensional features. To this end, it is a fundamental step to explore the relationship among different pixels in hyperspectral image classification, toward jointly handing both the lack of label and high dimensionality problems. In the hyperspectral images, the classification task can be benefited from the spatial layout information. In this paper, we propose a hyperspectral image classification method to address both the pixel spectral and spatial constraints, in which the relationship among pixels is formulated in a hypergraph structure. In the constructed hypergraph, each vertex denotes a pixel in the hyperspectral image. And the hyperedges are constructed from both the distance between pixels in the feature space and the spatial locations of pixels. More specifically, a feature-based hyperedge is generated by using distance among pixels, where each pixel is connected with its K nearest neighbors in the feature space. Second, a spatial-based hyperedge is generated to model the layout among pixels by linking where each pixel is linked with its spatial local neighbors. Both the learning on the combinational hypergraph is conducted by jointly investigating the image feature and the spatial layout of pixels to seek their joint optimal partitions. Experiments on four data sets are performed to evaluate the effectiveness and and efficiency of the proposed method. Comparisons to the state-of-the-art methods demonstrate the superiority of the proposed method in the hyperspectral image classification. ? 2013 IEEE.Accession Number: 20140217177888 -
Record 64 of
Title:A simple method for astigmatic compensation of folded resonator without Brewster window
Author(s):Qiao, Wen(1,2); Xiaojun, Zhang(1,2); Yonggang, Wang(3); Liqun, Sun(4); Hanben, Niu(2)Source: Optics Express Volume: 22 Issue: 3 DOI: 10.1364/OE.22.002309 Published: February 10, 2014Abstract:A folded resonator requires an oblique angle of incidence on the folded curved mirror, which introduces astigmatic distortions that limit the performance of the lasers. We present a simple method to compensate the astigmatism of folded resonator without Brewster windows for the first time to the best of our knowledge. Based on the theory of the propagation and transformation of Gaussian beams, the method is both effective and reliable. Theoretical results show that the folded resonator can be compensated astigmatism completely when the following two conditions are fulfilled. Firstly, when the Gaussian beam with a determined size beam waist is obliquely incident on an off-axis concave mirror, two new Gaussian beam respectively in the tangential and sagittal planes are formed. Another off-axis concave mirror is located at another intersection point of the two new Gaussian beams. Secondly, adjusting the incident angle of the second concave mirror or its focal length can make the above two Gaussian beam coincide in the image plane of the second concave mirror, which compensates the astigmatic aberration completely. A side-pumped continues-wave (CW) passively mode locked Nd:YAG laser was taken as an example of the astigmatically compensated folded resonators. The experimental results show good agreement with the theoretical predictions. This method can be used effectively to design astigmatically compensated cavities resonator of high-performance lasers. ? 2014 Optical Society of America.Accession Number: 20140817356314 -
Record 65 of
Title:Square wave modulation to eliminate the influence of Wollaston prism nonlinear coefficients on spatial angle measurement
Author(s):Lu, Weiguo(1); Wu, Yiming(1); Gao, Limin(1); Li, Chunyan(1,2); Xiao, Maosen(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 7 DOI: Published: July 25, 2014Abstract:A spatial angle measurement model was established based on polarizing beam splitting principle of Wollaston prism. The influence of exit light intensity from Wollaston prism on the system angle measurement accuracy was made by theoretical analysis and simulation briefly. The simulation results show that the exit light intensity deviates from the Malus' law, a certain nonlinear deviation is presented, and there is a great influence of the nonlinear deviation of Wollaston prism on the angle measurement accuracy of spatial angle measurement, the practical value of the device is reduced. Furthermor, a method of square wave magneto- optical modulation was presented to improve the angle measurement accuracy, which effectively eliminated the influence of nonlinear coefficients of Wollaston prism, fluctuations of magneto-optical glass modulation, differences of circuit gain and fluctuations of the light intensity. Finally, by doing relevant experiments, the system angle measurement accuracy can reach 15″ in the range of-8° to+8° by using this method.Accession Number: 20143600062412 -
Record 66 of
Title:A radiometric varying robust stereo matching algorithm
Author(s):Cao, Xiaoqian(1,2); Ma, Caiwen(1)Source: Jiqiren/Robot Volume: 36 Issue: 5 DOI: 10.13973/j.cnki.robot.2014.0634 Published: September 1, 2014Abstract:In order to improve the matching rate of radiometric varying stereo images, a novel stereo matching algorithm based on the improved epipolar distance transformation in log-chromaticity space is proposed. In log-chromaticity space, the intensity proportion of stereo image pairs is computed firstly according to raw disparity map; secondly, epipolar distance transformation is performed on left and right images respectively using proportional intensity deviation parameters; at last, the final disparity map is acquired by the belief propagation method. Theoretically, the matching rate of the proposed algorithm is independent of radiometric varying situations including differences in light source's position, spectrum, intensity and the parameters setting of cameras. Experimental results indicate that the matching rate of the proposed algorithm is improved at most 60% comparing with the original epipolar distance transformation algorithm and at most 78% comparing with the state of art algorithms such as ANCC (adaptive normalized cross correlation) when applied to textureless image pairs.Accession Number: 20144700237808 -
Record 67 of
Title:Learning hash functions using sparse reconstruction
Author(s):Yuan, Yong(1); Lu, Xiaoqiang(1); Li, Xuelong(1)Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/2632856.2632883 Published: 2014Abstract:Approximate nearest neighbor (ANN) search is becoming an increasingly important technique in large-scale problems. Recently many approaches have been developed due to fast query and low storage cost. Although most of them have realized the importance of the data structure, they neglected the sparse relationship of the data. To build a balance between the adjusted covariance matrix and the minimum reconstruction error of data points, this paper proposes a novel method based on sparse reconstruction to learn more compact binary codes under l2;1-norm constraint. Experiments demonstrate that the proposed method, named as sparse reconstruction hashing, outperforms several other state-of-the-art methods when tested on a few benchmark datasets. Copyright 2014 ACM.Accession Number: 20143318062185 -
Record 68 of
Title:Person re-identification by bidirectional projection
Author(s):Liu, Lina(1); Lu, Xiaoqiang(1); Yuan, Yuan(1); Li, Xuelong(1)Source: ACM International Conference Proceeding Series Volume: Issue: DOI: 10.1145/2632856.2632887 Published: 2014Abstract:Person re-identification plays an important role in video surveillance system. It can be regarded as an image retrieval process which aims to find the same person in multi-camera networks. Many existing methods learn a pairwise similarity measure by mapping the raw feature to a latent subspace to make the data more discriminative. However, most of these methods project all the data into the same subspace ignoring the different characteristics that the same person and different person hold. To solve the aforementioned problem, a pairwise based method is proposed by projecting the raw feature onto two discriminative subspaces according to whether a image pair is of the same class. The proposed method constructs a relative and pairwise model by using the logistic loss function to give a soft measure of the pairwise loss. Meanwhile, a trace norm regularization is used to create the convexity of the objective function, which also help to limit the dimension of the subspaces. Experiments carried on the benchmark dataset VIPeR show that the proposed model obtains better results compared with state-of-the-art methods. Copyright 2014 ACM.Accession Number: 20143318062182 -
Record 69 of
Title:Design and implementation of integrated diagnostic beam fast automatic alignment system
Author(s):Wang, Zheng-Zhou(1,2); Wang, Wei(1,2); Hu, Bing-Liang(1); Wang, Wei(1); Cao, Shi-Kang(1); Li, Dong-Jian(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 5 DOI: 10.3788/gzxb20144305.0512005 Published: May 2014Abstract:Parallel processing, fast convergent motor model and characteristic points extracted from the smallest outer circle were proposed to design the automatic alignment system, which can integrated diagnostic fast automatic alignment. First, all the alignment steps were executed in parallel and serial-parallel mode, and the important steps were reduced to unit alignment model. Second, the mathematical model for fast automatic alignment was used and the fast convergent algorithm of the unit alignment model was implemented. Finally, according to the characteristics of small laser spot, which contrast was low, distribution was asymmetrical, spot was not complete, the 100 characteristic points were extracted from the smallest outer circle and any two points distance was maximal, then a new method of circle fitting using least square method to calculate small laser spot center was proposed. Through the improvement of the above three aspects, alignment time reduced from 40 minutes to 8 minutes before the three aspects were optimized, the error of small laser spot centre is less than 2 pixels, and meet the experiment requirements.Accession Number: 20142617873991 -
Record 70 of
Title:Aerial vehicle astronomy autonomous navigation technology
Author(s):Liang, Dongsheng(1,2); Liu, Zhaohui(1); Liu, Wen(1); Yuan, Hui(1,2); Liu, Fucheng(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 9 DOI: Published: September 25, 2014Abstract:In allusion to the deficiencies of traditional inertial celestial integrated algorithm and selection uncertainty of the NAVSTAR, an algorithm based on SINS/CNS deeply integrated navigation with single star was proposed in this paper for the navigation system of long duration aero crafts. The error characteristics of inertial navigation and the star observation of two-gimbal were modeled exactly, and the advantages of both were analyzed and synthesized, the data of single star observation angle and inertial navigation was fused with high accuracy completely. In the height channel, barometric altimeter was introduced for altitude error damping. The design of the Kalman filter achieved optimal estimation of INS error. With analysis of the system observability, optimal NAVSTAR selection criteria was successfully brought out, effective solution to the problem of declining performance of the algorithm in the part of the observation angle was solved effectively. The simulation results of the algorithm show that the long positioning accuracy is better than traditional algorithm. Optimal NAVSTAR selection criteria effectively improve the robustness of the algorithm, which has a higher significance to theoretical study and engineering application value.Accession Number: 20144400132560 -
Record 71 of
Title:Corner detection via multi-scale autocorrelation matrix on edge contours
Author(s):Wang, Hao(1,2); Zhou, Zuo-Feng(1); Cao, Jian-Zhong(1); Yan, Su(1)Source: Xi Tong Gong Cheng Yu Dian Zi Ji Shu/Systems Engineering and Electronics Volume: 36 Issue: 6 DOI: 10.3969/j.issn.1001-506X.2014.06.32 Published: June 2014Abstract:To reduce the influence of edge tiny changes and noise on the corner detection and improve the detection accuracy, a new corner detection algorithm using multi-scale autocorrelation matrix on edge contours is proposed. Firstly, the edge contour of an image is extracted by an edge detector. Meanwhile, the image is smoothed by the Gaussian kernel function with different scales. For each pixel on the contour, the variation information of gray magnitude on certain scales can be obtained by the differential operator and will be used to construct the autocorrelation matrix. Finally, the normalized eigenvalue of autocorrelation matrices on different scales is defined as the new corner measure. An edge pixel is specified as a corner when its measure is not only above the preset threshold but also the local maximum in a small region. Experimental results show that the proposed algorithm achieves better detection accuracy and fewer false corners.Accession Number: 20142917947377 -
Record 72 of
Title:Color fusion system of low-light level and infrared images based on multi-core DSP
Author(s):Deng, Chan(1,2); Liu, Wen(1); Huang, Biao(1,2); Zhan, Zhenhuan(1,2); Zhang, Xin(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 9 DOI: Published: September 25, 2014Abstract:For the color fusion of low-level light and infrared images have the characteristics of strong real-time performance and a large quantity of data, a low-level light and infrared dual channel real-time image fusion system based on multi-core digital signal processor (DSP) and field programmable gate array (FPGA) was put forward. Cyclone IV FPGA of Altera Co.Ltd. with serial transceivers was chose to complete the image information collection, preprocessing and all kinds of control of peripheral equipment, while the newest 8 core high performance fixed point and floating point DSP TMS320C6678 of TI Co. Ltd. was used to realize image fusion. The data transmission was achieved between field programmable gate array and multi-core digital signal processor through the high-speed Serial RapidIO (SRIO) interface, and then color transmission in YUV color space as well. When the color information of the color image in the day light was passed to the fusion image, it was closer to natural color and could reflect richer scene information as much as possible. Experiment shows that this system can realize realtime image fusion and useful color transmission, is suitable for the color fusion system applications of the dual channel video natural sense in the dynamic scenarios.Accession Number: 20144400132262