2016
2016
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Record 325 of
Title:Study of aberration characteristic of off-axis reflective system
Author(s):Pang, Zhihai(1); Fan, Xuewu(1); Ren, Guorui(1); Ding, Jiaoteng(1); Xu, Liang(1); Feng, Liangjie(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 45 Issue: 6 DOI: 10.3788/IRLA201645.0618002 Published: June 25, 2016Abstract:Based on the 3rd vector wavefront aberration theory of axial symmetry optical system, the vector aberration expansions of off-axis optical system was obtained by pupil zoomed factorial and pupil decenter vector in this paper. It is known through the analysis that the off-axis optical system's aberration are still composed of 3rd spherical aberration 3rd coma and 3rd astigmatism. Due to the impact of pupil zoomed factorial, the decrease of the off-axis optical system's aberration coefficients were different proportion. The higher-order pupil aberration of coaxial system will induce low-order pupil aberration into off-axis mirror system. For example, if the coaxial system is not corrected for 3rd spherical aberration, it will introduce not only the spherical but also the constant coma and astigmatism into off-axis system. The aberration of off-axis system will not be asymmetry by the field center because the induced low-order aberration, and there maybe have an aberration zero point outside the center field of the view. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20162702564088 -
Record 326 of
Title:Superpixel Optimization Using Higher Order Energy
Author(s):Peng, Jianteng(1); Shen, Jianbing(1); Yao, Angela(2); Li, Xuelong(3)Source: IEEE Transactions on Circuits and Systems for Video Technology Volume: 26 Issue: 5 DOI: 10.1109/TCSVT.2015.2430631 Published: May 2016Abstract:A novel superpixel extraction algorithm using a higher order energy optimization framework is proposed in this paper. We first adopt the k-means clustering technique to quickly get an initial superpixel result. Then a higher order energy function is employed to optimize and refine these initial superpixels. We use a more general higher order energy function that includes a first-order data term, a second-order smoothness term, and a higher order term. The presegments are employed to provide the prior information of sufficient edges and segment regions for our higher order energy term. According to the texture measurement in different local regions, our algorithm adaptively computes the proper ratios of different energy terms to obtain a better superpixel performance. The experimental results demonstrate that our method using the higher order energy generates better results with well-aligned boundaries and homogeneous effects than the existing superpixel algorithms. ? 2015 IEEE.Accession Number: 20162202437127 -
Record 327 of
Title:Query-Adaptive Reciprocal Hash Tables for Nearest Neighbor Search
Author(s):Liu, Xianglong(1); Deng, Cheng(2); Lang, Bo(1); Tao, Dacheng(3); Li, Xuelong(4)Source: IEEE Transactions on Image Processing Volume: 25 Issue: 2 DOI: 10.1109/TIP.2015.2505180 Published: February 1, 2016Abstract:Recent years have witnessed the success of binary hashing techniques in approximate nearest neighbor search. In practice, multiple hash tables are usually built using hashing to cover more desired results in the hit buckets of each table. However, rare work studies the unified approach to constructing multiple informative hash tables using any type of hashing algorithms. Meanwhile, for multiple table search, it also lacks of a generic query-adaptive and fine-grained ranking scheme that can alleviate the binary quantization loss suffered in the standard hashing techniques. To solve the above problems, in this paper, we first regard the table construction as a selection problem over a set of candidate hash functions. With the graph representation of the function set, we propose an efficient solution that sequentially applies normalized dominant set to finding the most informative and independent hash functions for each table. To further reduce the redundancy between tables, we explore the reciprocal hash tables in a boosting manner, where the hash function graph is updated with high weights emphasized on the misclassified neighbor pairs of previous hash tables. To refine the ranking of the retrieved buckets within a certain Hamming radius from the query, we propose a query-adaptive bitwise weighting scheme to enable fine-grained bucket ranking in each hash table, exploiting the discriminative power of its hash functions and their complement for nearest neighbor search. Moreover, we integrate such scheme into the multiple table search using a fast, yet reciprocal table lookup algorithm within the adaptive weighted Hamming radius. In this paper, both the construction method and the query-adaptive search method are general and compatible with different types of hashing algorithms using different feature spaces and/or parameter settings. Our extensive experiments on several large-scale benchmarks demonstrate that the proposed techniques can significantly outperform both the naive construction methods and the state-of-the-art hashing algorithms. ? 1992-2012 IEEE.Accession Number: 20161502227985 -
Record 328 of
Title:Yb-doped large-mode-Area aluminosilicate laser fibre fabricated by chelate precursor doping technique
Author(s):Peng, Kun(1,2,3); Wang, Zhen(1,2,3); Zhan, Huan(2); Ni, Li(2); Gao, Cong(2); Wang, Xiaolong(2); Wang, Yuying(2); Wang, Jianjun(2); Jing, Feng(2); Lin, Aoxiang(2)Source: Electronics Letters Volume: 52 Issue: 23 DOI: 10.1049/el.2016.3350 Published: November 10, 2016Abstract:A modified chelate precursor doping technique using high-purity materials and accurate gas flow control system is proposed to fabricate an efficient ytterbium-doped large-mode-Area silica fibre for laser development. This technique enables to make homogeneous large-core preform with symmetrical shape, relatively low numerical aperture of ～0.06 and large-core size of over 4 mm. Homemade preform was drawn into standard fibre for testing and fully characterised by electron probe microanalysis and time-of-flight secondary ion mass spectrometry. On the basis of two-stage master oscillator power amplifier system, 1 kW laser output with slope efficiency of 81.0% was realised at ～1064 nm. ? The Institution of Engineering and Technology 2016.Accession Number: 20164502994209 -
Record 329 of
Title:Research on the airborne SINS/CNS integrated navigation system assisted by BD navigation system
Author(s):Xie, Mei-Lin(1); Yang, Xiao-Xu(1); Han, Jun-Feng(1); Wei, Yu(1); Yue, Peng(2); Deng, Xiao-Guo(1); Huang, Wei(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9796 Issue: DOI: 10.1117/12.2229568 Published: 2016Abstract:When the star navigation system working during the day, the strong sky background radiation lead to a result that the detect target light is too weak, in the field of view, because of the limitation on the number of the navigation star, usually choose the single star navigation work mode. In order to improve the reliability of the airborne SINS/CNS integrated navigation system, meet the demand of the long-endurance and high precision navigation, use the tight combination way, single star patrol algorithm to get the position and attitude. There exists filtering divergence problem because of the model error and the system measurement noise is uncertain, put forward a new fuzzy adaptive kalman filtering algorithm. Adjust the size of measurement noise to prevent the filter divergence; the positioning accuracy of integrated navigation system can be improved through BeiDou satellite. Without the information of BeiDou satellite, based on the level of the virtual reference, the navigation precision of integrated navigation system can be ensured over a period of time. ? 2016 SPIE.Accession Number: 20163502747269 -
Record 330 of
Title:Similarity Constraints-Based Structured Output Regression Machine: An Approach to Image Super-Resolution
Author(s):Deng, Cheng(1); Xu, Jie(1); Zhang, Kaibing(2); Tao, Dacheng(3); Gao, Xinbo(1); Li, Xuelong(4)Source: IEEE Transactions on Neural Networks and Learning Systems Volume: 27 Issue: 12 DOI: 10.1109/TNNLS.2015.2468069 Published: December 2016Abstract:For regression-based single-image super-resolution (SR) problem, the key is to establish a mapping relation between high-resolution (HR) and low-resolution (LR) image patches for obtaining a visually pleasing quality image. Most existing approaches typically solve it by dividing the model into several single-output regression problems, which obviously ignores the circumstance that a pixel within an HR patch affects other spatially adjacent pixels during the training process, and thus tends to generate serious ringing artifacts in resultant HR image as well as increase computational burden. To alleviate these problems, we propose to use structured output regression machine (SORM) to simultaneously model the inherent spatial relations between the HR and LR patches, which is propitious to preserve sharp edges. In addition, to further improve the quality of reconstructed HR images, a nonlocal (NL) self-similarity prior in natural images is introduced to formulate as a regularization term to further enhance the SORM-based SR results. To offer a computation-effective SORM method, we use a relative small nonsupport vector samples to establish the accurate regression model and an accelerating algorithm for NL self-similarity calculation. Extensive SR experiments on various images indicate that the proposed method can achieve more promising performance than the other state-of-the-art SR methods in terms of both visual quality and computational cost. ? 2015 IEEE.Accession Number: 20173404066415 -
Record 331 of
Title:Design of Fiber Bragg Grating automatic analysis test system based on LabVIEW
Author(s):Liu, Chun-Tong(1); Li, Hong-Cai(1); He, Zhen-Xin(1); Wu, Guo-Jun(2)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 45 Issue: 2 DOI: 10.3788/gzxb20164502.0206002 Published: February 1, 2016Abstract:For the purpose of realizing the Fiber Bragg Grating (FBG) sensing system automated test and analysis, a friendly interface of FBG sensing test system based on LabVIEW was designed by using the remote control port of Q8384 spectrometer. The strain/force integrated tester was used for tension test of a steel beam with embedded FBG packaged, the experiment data was acquired and analyzed by LabVIEW automatic testing platform, the results were in line with the design expectations, and the system realized the real-time monitoring and data storage capabilities. The tested device is easy to manage, and the direct operation on spectrometer is avoided, which can extend the service life of the spectrometer. ? 2016, Science Press. All right reserved.Accession Number: 20161402193829 -
Record 332 of
Title:Applications of photonic crystal in wavelength multiplex visualization
Author(s):Qian, Shi(1); Lei, Zhang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10154 Issue: DOI: 10.1117/12.2247307 Published: 2016Abstract:The triple-channel photonic crystal filters are proposed designed. These devices have advantages of better filtering effect and high wavelength accuracy. In wavelength multiplex visualization, these filters can bring different wavelength of view entering into eyes so that stereo images are formed. we discuss the problem about minimization of the angle shift.The simulation shows that higher-index material and more high-index material in a basic period can decrease the angle shift. ? 2016 SPIE.Accession Number: 20170503309978 -
Record 333 of
Title:Optical Bloch oscillations and Zener tunneling of Airy beams in ionic-type photonic lattices
Author(s):Xiao, Fajun(1); Zhu, Weiren(2); Shang, Wuyun(1); Wang, Meirong(1); Zhang, Peng(4); Liu, Sheng(1); Premaratne, Malin(3); Zhao, Jianlin(1)Source: Optics Express Volume: 24 Issue: 16 DOI: 10.1364/OE.24.018332 Published: August 8, 2016Abstract:We report on the existence of optical Bloch oscillations (OBOs) and Zener tunneling (ZT) of Airy beams in ionic-type photonic lattices with a refractive index ramp. Different from their counterparts in uniform lattices, Airy beams undergoing OBOs show an alternatively switched concave and convex trajectory as well as a periodical revival of input beam profiles. Moreover, the ionic-type photonic lattice established in photorefractive crystal exhibits a reconfigurable lattice structure, which provides a flexible way to tune the amplitude and period of the OBOs. Remarkably, it is demonstrated that the band gap of the lattice can be readily controlled by rotating the lattice inducing beam, which forces the ZT rate to follow two significant different decay curves amidst decreasing index gradient. Our results open up new possibilities for all-optical switching, routing and manipulation of Airy beams. ? 2016 Optical Society of America.Accession Number: 20163802813029 -
Record 334 of
Title:SERF: A Simple, Effective, Robust, and Fast Image Super-Resolver from Cascaded Linear Regression
Author(s):Hu, Yanting(1); Wang, Nannan(2); Tao, Dacheng(3); Gao, Xinbo(1); Li, Xuelong(4)Source: IEEE Transactions on Image Processing Volume: 25 Issue: 9 DOI: 10.1109/TIP.2016.2580942 Published: September 2016Abstract:Example learning-based image super-resolution techniques estimate a high-resolution image from a low-resolution input image by relying on high- and low-resolution image pairs. An important issue for these techniques is how to model the relationship between high- and low-resolution image patches: most existing complex models either generalize hard to diverse natural images or require a lot of time for model training, while simple models have limited representation capability. In this paper, we propose a simple, effective, robust, and fast (SERF) image super-resolver for image super-resolution. The proposed super-resolver is based on a series of linear least squares functions, namely, cascaded linear regression. It has few parameters to control the model and is thus able to robustly adapt to different image data sets and experimental settings. The linear least square functions lead to closed form solutions and therefore achieve computationally efficient implementations. To effectively decrease these gaps, we group image patches into clusters via k-means algorithm and learn a linear regressor for each cluster at each iteration. The cascaded learning process gradually decreases the gap of high-frequency detail between the estimated high-resolution image patch and the ground truth image patch and simultaneously obtains the linear regression parameters. Experimental results show that the proposed method achieves superior performance with lower time consumption than the state-of-the-art methods. ? 2016 IEEE.Accession Number: 20163002639200 -
Record 335 of
Title:Multi-channel photonic crystal filters with superposed structure
Author(s):Shi, Qian(1); Zhang, Lei(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10154 Issue: DOI: 10.1117/12.2247445 Published: 2016Abstract:In this paper, photonic crystal-based filters are proposed. It is different from the narrow band filter with regular channels that Farbry-Perot interference filter and short wave-pass filters are overlapped to the multi-channel photonic crystal filters. The multi-channel photonic crystal filters have two bands in 428nm-449nm of blue light and 535nm-590nm of green light, the average transmittance is over 90%,which are able to meet the requirements of the projection optics. The brightness and color purity of the system are both improved. ? 2016 SPIE.Accession Number: 20170503309990 -
Record 336 of
Title:Free-form optical elements corrected aberrations of optical system
Author(s):Pang, Zhihai(1); Fan, Xuewu(1); Ma, Zhen(1); Zou, Gangyi(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 36 Issue: 5 DOI: 10.3788/AOS201636.0522001 Published: May 10, 2016Abstract:The optical element of free-form surface can be expressed by the fringe Zernike polynomial and the terms of initial spherical sag, coma and astigmatism are transformed into the vector forms. Based on the vector wave aberration theory, the free-form optical element characteristic of optical system initial aberration correction is analyzed. Through the analysis, the free-form surfaces in optical system have different aberration emendation specialties at different positions. The free-form optical element can be corrected in full field of view for constant initial aberration as a stop aperture (entrance pupil or exit pupil) in optical system. When the free-form surface is far from the stop aperture of optical system, due to the scaling and offset of the imaging beam aperture for an off-axis field point, the free-form surface can correcte the asymmetric initial aberration, and the relationship of different initial aberration and field of view is different. ? 2016, Chinese Lasers Press. All right reserved.Accession Number: 20162102427159