2017
2017
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Record 85 of
Title:Fast Spectral Clustering with efficient large graph construction
Author(s):Zhu, Wei(1); Nie, Feiping(1); Li, Xuelong(2)Source: ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings Volume: Issue: DOI: 10.1109/ICASSP.2017.7952605 Published: June 16, 2017Abstract:Spectral clustering has been regarded as a powerful tool for unsupervised tasks despite its excellent performance, the high computational cost has become a bottleneck which limits its application for large scale problems. Recent studies on anchor-based graph can partly alleviate the problem, however, it is still a great challenge to deal with such data with both high performance and high efficiency. In this paper, we propose Fast Spectral Clustering (FSC) to efficiently deal with large scale data. The proposed method first constructs anchor-based similarity graph with Balanced K-means based Hierarchical K-means (BKHK) algorithm, and then performs spectral analysis on the graph. The overall computational complexity is O(ndm), where n is the number of samples, d is the number of features, and m is the number of anchors. Comprehensive experiments on several large scale data sets demonstrate the effectiveness and efficiency of the proposed method. ? 2017 IEEE.Accession Number: 20172903954917 -
Record 86 of
Title:Calculation of Optical Transfer Function for Image Motion Based on Statistical Moments
Author(s):Tian, Liude(1,2); Wang, Tao(1); Zhao, Huaixue(1); Liu, Yining(1); Zhao, Jianke(1); Zhou, Yan(1); Liu, Zhaohui(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 37 Issue: 12 DOI: 10.3788/AOS201737.1211002 Published: December 10, 2017Abstract:In order to evaluate the influence of the tracking and imaging platform on the modulation transfer function of the image accurately and provide a theoretical basis for the determination of the platform's technical specifications, an analytical and numerical model is established, which is used to calculate the movement optical transfer function by the image motion function. The truncation error of the finite term is given, and the truncation error is less than 10% when the 7 order approximation is taken. The proposed model includes analytic expressions of low frequency sinusoidal motion and high frequency sinusoidal motion. The tracking angular velocity errors of a tracking imaging platform are analyzed by frequency spectrum. The fundamental components of frequency spectrum are composed by multiple low frequency sinusoidal vibration components. Image motion caused by the tracking angular velocity error can be approximated to uniform linear motion at the exposure time scale. The modulation transfer function is calculated by the statistical moment method, and is almost equal to that calculated by the root mean square of the tracking angular velocity error. The calculated deviation is less than 0.01 at 200 mrad-1 frequency. Therefore, the root mean square error of the tracking angular velocity is a reasonable parameter describing the tracking stability of the tracking imaging platform. ? 2017, Chinese Lasers Press. All right reserved.Accession Number: 20181104894289 -
Record 87 of
Title:Polarization-based enhancement of ocean color signal for estimating suspended particulate matter: Radiative transfer simulations and laboratory measurements
Author(s):Liu, Jia(1,2); He, Xianqiang(2,3); Liu, Jiahang(1); Bai, Yan(2); Wang, Difeng(2); Chen, Tieqiao(1); Wang, Yihao(1); Zhu, Feng(1)Source: Optics Express Volume: 25 Issue: 8 DOI: 10.1364/OE.25.00A323 Published: April 17, 2017Abstract:Absorption and scattering by molecules, aerosols and hydrosols, and the reflection and transmission over the sea surface can modify the original polarization state of sunlight. However, water-leaving radiance polarization, containing embedded water constituent information, has largely been neglected. Here, the efficiency of the parallel polarization radiance (PPR) for enhancing ocean color signal of suspended particulate matter is examined via vector radiative transfer simulations and laboratory experiments. The simulation results demonstrate that the PPR has a slightly higher ocean color signal at the top-of-atmosphere as compared with that of the total radiance. Moreover, both the simulations and laboratory measurements reveal that, compared with total radiance, PPR can effectively enhance the normalized ocean color signal for a large range of observation geometries, wavelengths, and suspended particle concentrations. Thus, PPR has great potential for improving the ocean color signal detection from satellite. ?2017 Optical Society of America.Accession Number: 20171703601966 -
Record 88 of
Title:A universal pedestrian's foot-point and head-point recognition with improved motion detection algorithm
Author(s):Shi, Liu(1,2); Liu, Jiahang(1); Yihao, Wang(1)Source: 2017 2nd International Conference on Image, Vision and Computing, ICIVC 2017 Volume: Issue: DOI: 10.1109/ICIVC.2017.7984562 Published: July 18, 2017Abstract:Detecting pedestrians' spatial locations is a key, yet challenging task in video surveillance. From video sequences, we can apply motion detection algorithm to detect the whole pedestrians, and recognize pedestrians' foot-point locations with foot-point recognition method. While we propose a solution to recognize pedestrians' head-point locations for partially occluded pedestrians in complex scenes. Then, a few simple mappings can be used for converting head-point to foot-point and converting 2-D locations to 3-D spatial locations in computer vision. In this paper, we present a pixel-level background sample set motion detection approach based on Self-Balanced SENsitivity SEgmenter, coined SuBSENSE algorithm. Instead of using the same background/foreground segmentation criterion for low and high brightness distribution areas, we use completely different segmentation criterion for low and high brightness, respectively. Besides, for an actual scenario with camouflaged foreground objects, simple color and texture feature could not detect these motion objects. To best address these disadvantages, we introduce normalized color feature and extended local binary similarity pattern (ELBSP) operator by adaptive threshold to segment motion objects for high brightness while providing normalized color feature by perception-inspired confidence interval for high brightness. Due to the diversity of camera gesture in video images, we can't directly gain foot-point and head-point location from the results of motion detection. For foot-point, principal component analysis is employed in getting pedestrian's upright direction and mapping the whole object to this direction. Moreover, color feature, area feature, and position feature are utilized for detecting head-point. Experiments show that it outperforms original motion detection approach and several state-of-the-art methods, and can accurately obtain pedestrians' 2-D locations in real scenarios. ? 2017 IEEE.Accession Number: 20173804169208 -
Record 89 of
Title:A novel approach of an absolute coding pattern based on Hamiltonian graph
Author(s):Wang, Ya'nan(1,2); Wang, Huawei(1); Hao, Fusheng(1,2); Liu, Liqiang(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2257823 Published: 2017Abstract:In this paper, a novel approach of an optical type absolute rotary encoder coding pattern is presented. The concept is based on the principle of the absolute encoder to find out a unique sequence that ensures an unambiguous shaft position of any angular. We design a single-ring and a n-by-2 matrix absolute encoder coding pattern by using the variations of Hamiltonian graph principle. 12 encoding bits is used in the single-ring by a linear array CCD to achieve an 1080-position cycle encoding. Besides, a 2-by-2 matrix is used as an unit in the 2-track disk to achieve a 16-bits encoding pattern by using an area array CCD sensor (as a sample). Finally, a higher resolution can be gained by an electronic subdivision of the signals. Compared with the conventional gray or binary code pattern (for a 2n resolution), this new pattern has a higher resolution (2n?n) with less coding tracks, which means the new pattern can lead to a smaller encoder, which is essential in the industrial production. ? 2017 SPIE.Accession Number: 20171703607557 -
Record 90 of
Title:Study of imaging fiber bundle coupling technique in IR system
Author(s):Chen, Guoqing(1,2); Yang, Jianfeng(2); Yan, Xingtao(2); Song, Yansong(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10250 Issue: DOI: 10.1117/12.2266955 Published: 2017Abstract:Due to its advantageous imaging characteristic and banding flexibility, imaging fiber bundle can be used for line-plane-switching push-broom infrared imaging. How to precisely couple the fiber bundle in the optics system is the key to get excellent image for transmission. After introducing the basic system composition and structural characteristics of the infrared systems coupled with imaging fiber bundle, this article analysis the coupling efficiency and the design requirements of its relay lenses with the angle of the numerical aperture selecting in the system and cold stop matching of the refrigerant infrared detector. For an actual need, one relay coupling system has been designed with the magnification is -0.6, field of objective height is 4mm, objective numerical aperture is 0.15, which has excellent image quality and enough coupling efficiency. In the end, the push broom imaging experiment is carried out. The results show that the design meets the requirements of light energy efficiency and image quality. This design has a certain reference value for the design of the infrared fiber optical system. ? 2017 COPYRIGHT SPIE.Accession Number: 20171403518577 -
Record 91 of
Title:Small-period long-period fiber grating with improved refractive index sensitivity and dual-parameter sensing ability
Author(s):Shen, Fangcheng(1,2); Wang, Changle(2); Sun, Zhongyuan(2); Zhou, Kaiming(2,3); Zhang, Lin(2); Shu, Xuewen(1)Source: Optics Letters Volume: 42 Issue: 2 DOI: 10.1364/OL.42.000199 Published: January 15, 2017Abstract:We UV inscribe and characterize a long-period fiber grating with a period of 25 μm. A series of polarization-dependent dual-peak pairs can be seen in the transmission spectrum, even though only the symmetrical refractive index modification is introduced. The fabricated grating exhibits a lower temperature sensitivity compared with standard long-period gratings and an enhanced refractive index sensitivity of ～312.5 nm?RIU averaged from 1.315 to 1.395, which is more than four-fold higher than standard long-period gratings in this range. The full width at half-maximum of the fabricated grating is only about 0.6 nm, allowing for high-resolution sensing. Moreover, the grating period is so small that the attenuation dip corresponding to a high-order Bragg resonance can also be seen, which can act as a monitor of the unwanted perturbation to realize dual-parameter sensing. ? 2017 Optical Society of America.Accession Number: 20170303263044 -
Record 92 of
Title:Long period fiber grating around the dispersion turning point fabricated with a femtosecond laser
Author(s):Shen, Fangcheng(1); Zhou, Kaiming(2,3); Zhang, Lin(2); Shu, Xuewen(1)Source: Asia Communications and Photonics Conference, ACP Volume: 2017-August Issue: DOI: 10.1364/ACPC.2017.Su2A.104 Published: August 9, 2017Abstract:Long period fiber grating around the dispersion turning point, which exhibits high sensitivity to measurands such as temperature and refractive index, is fabricated in single mode fiber with a femtosecond laser for the first time. ? OSA 2017.Accession Number: 20181404984624 -
Record 93 of
Title:Small period long period grating with enhanced sensitivity in low refractive index region
Author(s):Shen, Fangcheng(1); Zhou, Kaiming(2,3); Zhang, Lin(2); Shu, Xuewen(1)Source: 2017 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2017 Volume: 2017-January Issue: DOI: 10.1109/CLEOPR.2017.8118766 Published: November 22, 2017Abstract:Long period grating with a grating period of 15 μm is fabricated with a femtosecond laser. Such a small period grating enables coupling of fundamental core mode with high order cladding modes that have effective refractive index close to water, and exhibits an enhanced sensitivity in low refractive index region. ? 2017 Institute of Electrical and Electronics Engineers Inc. All Rights Reserved.Accession Number: 20181304941974 -
Record 94 of
Title:Research on polarized optical properties of space target material
Author(s):Yuan, Bo(1,2); Gao, Jing(1); Yang, Fan-Chao(1,2); Hu, Bing-Liang(1); Gao, Xiao-Hui(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 46 Issue: 1 DOI: 10.3788/gzxb20174601.0116003 Published: January 1, 2017Abstract:Based on the bidirectional reflectance model, the polarization characteristics and spectral radiosities of four space target samples, such as carbon fiber, carburizing film, F46 and OSR, were measured. By calculating the Stokes parameters of the samples, the degrees of linear polarization and polarization orientations under multiple observing angles were obtained and recorded. The statistical results show that, the different samples have great differences in average and variance of the degree of linear polarization and Orientation. The analysis of the difference between the average and variance of samples can improve the effects in detecting and identifying simples efficiently and solve the "Same object with different spectrums" and "Foreign body in the same spectrum" problems occurred in spectroscopic techniques. The polarization property provides more optical information for remote sensing, which is an effective and reliable method for target recognition. ? 2017, Science Press. All right reserved.Accession Number: 20171103436784 -
Record 95 of
Title:Observation of spin and orbital rotation of red blood cell in dual-beam fibre-optic trap with transverse offset
Author(s):Chen, Xinlin(1); Xiao, Guangzong(1,2); Han, Xiang(1); Xiong, Wei(1); Luo, Hui(1); Yao, Baoli(2)Source: Journal of Optics (United Kingdom) Volume: 19 Issue: 5 DOI: 10.1088/2040-8986/aa66c1 Published: May 2017Abstract:The spin and orbital rotation of the red blood cell (RBC) are achieved simultaneously by introducing a transverse offset to the dual-beam fibre-optic trap. The motion type of the captured RBC could be controlled by adjusting the offset distance. When the offset distance is relatively small, the RBC is observed to spin in the trap centre, with the spin frequency increasing linearly with the offset distance. Once the offset distance is above a critical value, the RBC will rotate along an elliptic orbit, together with the spin motion. The orbital rotation frequency and spin frequency both decrease with the increased offset distance. This technique allows mixing and viewing living cells from different perspectives concurrently without exposing them to any mechanical contact, and is generally applicable to biological and medical research. ? 2017 IOP Publishing Ltd.Accession Number: 20171903644521 -
Record 96 of
Title:Brownian dynamics of the optically trapped spinning microparticles in low pressures
Author(s):Lang, Mengjiao(1); Xiong, Wei(1); Xiao, Guangzong(1,2); Han, Xiang(1); Tang, Jianxun(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10460 Issue: DOI: 10.1117/12.2284450 Published: 2017Abstract:Optical trap has become a powerful tool of biology and physics, since it has some useful functions such as optical rotator, optical spanner and optical binding. We present the translational motions in the transverse plane of a 4.4μm-diameter vaterite particle which is optically trapped in low pressures utilizing the Monte-Carlo method. We find that the air pressure around the microparticle plays an important part in the determination of dynamics of the trapped particle. According to the energy equipartition theorem, the position fluctuations of the optically trapped particle satisfy Maxwell-Bolzmann distributions. We present the features of particles' displacements and velocities changing with air pressures in detail, and find that the modulation of the trap stiffness makes a higher position variance. The mechanical quality factor Q larger than 10 induces a high peak of power spectral density. Our research presents a powerful tool towards further discovery of dynamical characteristics of optically trapped Brownian particles in low air pressures. ? 2017 SPIE.Accession Number: 20180304652990