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中国科学院国家科学图书馆机构知识库Sun, 15 Jul 2018 20:51:53 GMT2018-07-15T20:51:53ZSimulation and application of the emission line O19P18 of O-2 (a(1)Delta(g) ) dayglow near 1.27 mu m for wind observations from limb-viewing satellites
http://ir.opt.ac.cn:80/handle/181661/30417
题名: Simulation and application of the emission line O19P18 of O-2 (a(1)Delta(g) ) dayglow near 1.27 mu m for wind observations from limb-viewing satellites
作者: Wu, Kuijun; Fu, Di; Feng, Yutao; Li, Juan; Hao, Xiongbo; Li, Faquan
摘要: <p>
The O-2 (a(1)Delta(g)) emission near 1.27 gm has relatively bright signal and extended altitude coverage and provides an important means to remotely sense the compositional structures and dynamical features of the upper atmosphere globally. In this paper, we report the simulation and application of O-2 (a(1)Delta(g)) dayglow near 1.27 mu m for wind observations from limb-viewing satellites. A line by line radiative transfer model of the O-2 (a(1)Delta(g), v' = 0) -> O-2 (X-3 Sigma(g), v '' = 0) band is developed by taking both multiple scattering radiative transfer and nonlocal thermal equilibrium (non-LTE) models into account. The emission line O19P18 (7772.030 cm(-1)) with weak self-absorption, bright radiation intensity, and large spectral separation range is proved to be suitable for limb-viewing wind detection, due to its advantages of significantly lower cost, risk, and platform requirements. In order to ascertain the wind precision of O19P18, observations by a DASH-type (the Doppler asymmetric spatial heterodyne) instrument are simulated. The simulated results indicate a wind measurement precision of 1-2 m/s over an altitude range of 40 to 70 km in general, and possibly to 2-4 m/s due to a strong dependence on the spectral interference of the scattered sunlight background. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement</p>Fri, 13 Jul 2018 02:21:11 GMThttp://ir.opt.ac.cn:80/handle/181661/304172018-07-13T02:21:11ZPatch Alignment Manifold Matting
http://ir.opt.ac.cn:80/handle/181661/30416
题名: Patch Alignment Manifold Matting
作者: Li, Xuelong; Liu, Kang; Dong, Yongsheng; Tao, Dacheng
摘要: <p>
Image matting is generally modeled as a space transform from the color space to the alpha space. By estimating the alpha factor of the model, the foreground of an image can be extracted. However, there is some dimensional information redundancy in the alpha space. It usually leads to the misjudgments of some pixels near the boundary between the foreground and the background. In this paper, a manifold matting framework named Patch Alignment Manifold Matting is proposed for image matting. In particular, we first propose a part modeling of color space in the local image patch. We then perform whole alignment optimization for approximating the alpha results using subspace reconstructing error. Furthermore, we utilize Nesterov's algorithm to solve the optimization problem. Finally, we apply some manifold learning methods in the framework, and obtain several image matting methods, such as named ISOMAP matting and its derived Cascade ISOMAP matting. The experimental results reveal that the manifold matting framework and its two examples are effective when compared with several representative matting methods.</p>Fri, 13 Jul 2018 02:21:08 GMThttp://ir.opt.ac.cn:80/handle/181661/304162018-07-13T02:21:08ZCascaded Subpatch Networks for Effective CNNs
http://ir.opt.ac.cn:80/handle/181661/30415
题名: Cascaded Subpatch Networks for Effective CNNs
作者: Jiang, Xiaoheng; Pang, Yanwei; Sun, Manli; Li, Xuelong
摘要: <p>
Conventional convolutional neural networks use either a linear or a nonlinear filter to extract features from an image patch (region) of spatial size H x W (typically, H is small and is equal to W, e.g., H is 5 or 7). Generally, the size of the filter is equal to the size H x W of the input patch. We argue that the representational ability of equal-size strategy is not strong enough. To overcome the drawback, we propose to use subpatch filter whose spatial size h x w is smaller than H x W. The proposed subpatch filter consists of two subsequent filters. The first one is a linear filter of spatial size h x w and is aimed at extracting features from spatial domain. The second one is of spatial size 1 x 1 and is used for strengthening the connection between different input feature channels and for reducing the number of parameters. The subpatch filter convolves with the input patch and the resulting network is called a subpatch network. Taking the output of one subpatch network as input, we further repeat constructing subpatch networks until the output contains only one neuron in spatial domain. These subpatch networks form a new network called the cascaded subpatch network (CSNet). The feature layer generated by CSNet is called the csconv layer. For the whole input image, we construct a deep neural network by stacking a sequence of csconv layers. Experimental results on five benchmark data sets demonstrate the effectiveness and compactness of the proposed CSNet. For example, our CSNet reaches a test error of 5.68% on the CIFAR10 data set without model averaging. To the best of our knowledge, this is the best result ever obtained on the CIFAR10 data set.</p>Fri, 13 Jul 2018 02:21:04 GMThttp://ir.opt.ac.cn:80/handle/181661/304152018-07-13T02:21:04ZImage hashing with color vector angle
http://ir.opt.ac.cn:80/handle/181661/30414
题名: Image hashing with color vector angle
作者: Tang, Zhenjun; Li, Xuelong; Zhang, Xianquan; Zhang, Shichao; Dai, Yumin
摘要: <p>
Color vector angle (CVA) is an important feature of processing color images and has been successfully developed and used in real applications, such as edge detection, indexing and retrieval of images. However, it is unsolved how to apply the CVA to efficiently generating an image hash. Also, most image hashing algorithms choose luminance component of color image for hash generation and cannot well capture the color information of images. To tackle these issues, we study efficient image hashing algorithms with the histogram of CVAs, called HCVA hashing. The histogram is first extracted from those angles that are in the biggest circle inscribed inside the normalized image. And then, it is compressed to make a short hash. We conducted some experiments to assess the performance, and illustrated that the DCT (Discrete Cosine Transform) is the best one of that cooperating with HCVA at generating hashes, as well as the HCVA hashing is robust and promising. (C) 2018 Elsevier B.V. All rights reserved.</p>Fri, 13 Jul 2018 02:21:00 GMThttp://ir.opt.ac.cn:80/handle/181661/304142018-07-13T02:21:00Z快速空间测角系统中偏振棱镜消光比的影响
http://ir.opt.ac.cn:80/handle/181661/30413
题名: 快速空间测角系统中偏振棱镜消光比的影响
作者: 李春艳; 陆卫国; 乔琳
摘要: <p>
为了在一定平移范围内实现快速空间测角系统的测量功能,对一定入射及方位角的光束经过Glan-Taylor棱镜后导致的非均匀分布的消光比参数引起的系统测角误差进行了研究。首先,建立系统坐标系模型,采用光线追迹法及偏振光的琼斯矩阵描述方式,对格兰-泰勒棱镜消光比参数引起的测角误差进行了理论推导;接着,结合一定入射及方位角下非均匀分布的消光比参数,运用Matlab软件进行了仿真分析。最后,通过搭建实验平台,利用平移接收单元来模拟不同的入射方位及角度变化;根据实验值与仿真结果的对比分析,得出非均匀分布的消光比对测角精度的影响。结果表明,在一定的出射光范围内,入射角是影响消光比非均匀分布进而影响系统测角精度的主要因素,当方位角为90°时,系统测角误差较小;全方位角范围内系统测角误差随入射角的增大而显著增大,由此验证了理论分析的正确性。该研究成果对优化测角系统结构并进一步提高系统性能具有一定的指导意义。</p>Wed, 11 Jul 2018 03:25:23 GMThttp://ir.opt.ac.cn:80/handle/181661/304132018-07-11T03:25:23ZDiscriminant Analysis with graph learning for hyperspectral image classification
http://ir.opt.ac.cn:80/handle/181661/30412
题名: Discriminant Analysis with graph learning for hyperspectral image classification
作者: Chen, Mulin; Wang, Qi; Li, Xuelong
摘要: <p>
Linear Discriminant Analysis (LDA) is a widely-used technique for dimensionality reduction, and has been applied in many practical applications, such as hyperspectral image classification. Traditional LDA assumes that the data obeys the Gaussian distribution. However, in real-world situations, the high-dimensional data may be with various kinds of distributions, which restricts the performance of LDA. To reduce this problem, we propose the Discriminant Analysis with Graph Learning (DAGL) method in this paper. Without any assumption on the data distribution, the proposed method learns the local data relationship adaptively during the optimization. The main contributions of this research are threefold: (1) the local data manifold is captured by learning the data graph adaptively in the subspace; (2) the spatial information within the hyperspectral image is utilized with a regularization term; and (3) an efficient algorithm is designed to optimize the proposed problem with proved convergence. Experimental results on hyperspectral image datasets show that promising performance of the proposed method, and validates its superiority over the state-of-the-art. ? 2018 by the authors.</p>Tue, 10 Jul 2018 08:37:30 GMThttp://ir.opt.ac.cn:80/handle/181661/304122018-07-10T08:37:30ZInfluences of high-order dispersion on temporal and spectral properties of microcavity solitons
http://ir.opt.ac.cn:80/handle/181661/30411
题名: Influences of high-order dispersion on temporal and spectral properties of microcavity solitons
作者: Liu, Mulong; Wang, Leiran; Sun, Qibing; Li, Siqi; Ge, Zhiqiang; Lu, Zhizhou; Zeng, Chao; Wang, Guoxi; Zhang, Wenfu; Hu, Xiaohong; Zhao, Wei
摘要: <p>
We theoretically and numerically investigate the effects of high-order dispersion (HOD) on microcavity solitons, both in time and frequency domain with an extended normalized Lugiato–Lefever equation (LLE). The observed temporal drift of bright and dark solitons is shown to originate from high-odd-order dispersion, while the sign determines the direction of soliton movement and the amplitude decides the drift speed. HOD can also be introduced to stabilize the breathing bright and dark cavity solitons. In spectral domain, the nonlinear symmetry breaking is mainly introduced by third-order dispersion, whereas both third- and fourth-order dispersion can introduce dispersive wave accompanied by soliton tail oscillation. This work could give insight for exploring detailed intracavity pulse dynamics and spectral characteristics of Kerr combs influenced by HOD, as well as provide a viable route to delicate control of Kerr comb generation through tailoring the dispersion parameters. ? 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.</p>Tue, 10 Jul 2018 08:37:27 GMThttp://ir.opt.ac.cn:80/handle/181661/304112018-07-10T08:37:27ZArbitrary multiple beam forming by two cascaded liquid crystal optical phased arrays
http://ir.opt.ac.cn:80/handle/181661/30410
题名: Arbitrary multiple beam forming by two cascaded liquid crystal optical phased arrays
作者: Wu, Liang; Wang, Xiangru; He, Xiaoxian; Huang, Ziqiang; Huang, Xinning; Xiong, Caidong
摘要: <p>
A new method for non-mechanical laser beam splitting and steering is demonstrated. Two cascaded liquid crystal optical phased arrays (LC-OPAs) controllably modulate the amplitude and phase of an incident laser beam to realize the near-field wavefronts of multiple simultaneous beams with arbitrary directions. Diffraction between the two arrays is avoided by precise 4-f imaging from one LC-OPA to the other (array resolution 1×1920). In the method of cascaded amplitude and phase (CAP) devices, numerical simulation results show the characteristics of amplitude and phase modulation profiles, as well as the far-field intensity patterns. Both the numerical and experimental results clearly demonstrate the capabilities of fast multi-beam forming with high efficiency (>85%, 4 beams) and accuracy (deviation ? 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement</p>Tue, 10 Jul 2018 08:37:24 GMThttp://ir.opt.ac.cn:80/handle/181661/304102018-07-10T08:37:24ZEffects of capacitance ratio on the image linearity of capacitive division image readout
http://ir.opt.ac.cn:80/handle/181661/30409
题名: Effects of capacitance ratio on the image linearity of capacitive division image readout
作者: Lei, Fanpu; Bai, Yonglin; Zhu, Bingli; Wang, Bo; Bai, Xiaohong; Hou, Xun
摘要: <p>
Capacitive division readout anode has the advantages of simple manufacture technology and high spatial resolution. Linearity of the restored image is limited by the relationship between the values of C (charge divide capacitor), Cs(parasitic capacitor), Cd(capacitor introduced by diagonal electrode) and Cp(perimeter capacitor). This paper describes a discrete capacitance matrix to investigate the dependence of image linearity on capacitor ratios, including C/Cs, C/Cdand(N-1)C/Cp(N is the number of nodes in each row of the capacitance matrix). Results presents that image nonlinearity varies monotonically with C/Cs, C/Cdand(N-1)C/Cp. The effect of these capacitors on the linearity of image can be negligible when C/Csis greater than 100, C/Cdis greater than 10 and (N-1)C/Cpis smaller than 0.1. The reliability of the simulation results is verified by experiments. The RMS nonlinearity of capacitive anode is expected to less than 0.71%. ? 2018 Elsevier B.V.</p>Tue, 10 Jul 2018 08:37:21 GMThttp://ir.opt.ac.cn:80/handle/181661/304092018-07-10T08:37:21ZOn-chip entangled D-level photon states - scalable generation and coherent processing
http://ir.opt.ac.cn:80/handle/181661/30408
题名: On-chip entangled D-level photon states - scalable generation and coherent processing
作者: Kues, M.; Reimer, C.; Roztocki, P.; Cortés, L. Romero; Sciara, S.; Wetzel, B.; Zhang, Y.; Cino, A.; Chu, S.T.; Little, B.E.; Moss, D.J.; Caspani, L.; Azaña, J.; Morandotti, R.
摘要: <p>
Exploiting a micro-cavity-based quantum frequency comb, we demonstrate the on-chip generation of high-dimensional entangled quantum states with a Hilbert-space dimensionality larger than 100, and introduce a coherent control approach relying on standard telecommunications components. ? OSA 2018.</p>Tue, 10 Jul 2018 07:16:39 GMThttp://ir.opt.ac.cn:80/handle/181661/304082018-07-10T07:16:39Z