2015
2015
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Record 169 of
Title:Image compression based on GPU encoding
Author(s):Bai, Zhaofeng(1,2); Qiu, Yuehong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9631 Issue: DOI: 10.1117/12.2197078 Published: 2015Abstract:With the rapid development of digital technology, the data increased greatly in both static image and dynamic video image. It is noticeable how to decrease the redundant data in order to save or transmit information more efficiently. So the research on image compression becomes more and more important. Using GPU to achieve higher compression ratio has superiority in interactive remote visualization. Contrast to CPU, GPU may be a good way to accelerate the image compression. Currently, GPU of NIVIDIA has evolved into the eighth generation, which increasingly dominates the high-powered general purpose computer field. This paper explains the way of GPU encoding image. Some experiment results are also presented. ? 2015 SPIE.Accession Number: 20154501514846 -
Record 170 of
Title:Improvement and implementation for Canny edge detection algorithm
Author(s):Yang, Tao(1,2); Qiu, Yue-Hong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9631 Issue: DOI: 10.1117/12.2197080 Published: 2015Abstract:Edge detection is necessary for image segmentation and pattern recognition. In this paper, an improved Canny edge detection approach is proposed due to the defect of traditional algorithm. A modified bilateral filter with a compensation function based on pixel intensity similarity judgment was used to smooth image instead of Gaussian filter, which could preserve edge feature and remove noise effectively. In order to solve the problems of sensitivity to the noise in gradient calculating, the algorithm used 4 directions gradient templates. Finally, Otsu algorithm adaptively obtain the dual-threshold. All of the algorithm simulated with OpenCV 2.4.0 library in the environments of vs2010, and through the experimental analysis, the improved algorithm has been proved to detect edge details more effectively and with more adaptability. ? 2015 SPIE.Accession Number: 20154501514850 -
Record 171 of
Title:A 1.7-ps pulse mode-locked Yb3+:Sc2SiO5 laser with a reflective graphene oxide saturable absorber
Author(s):Ge, Ping-Guang(1); Su, Li-Ming(1); Liu, Jie(1); Zheng, Li-He(2); Su, Liang-Bi(2); Xu, Jun(2); Wang, Yong-Gang(3)Source: Chinese Physics B Volume: 24 Issue: 1 DOI: 10.1088/1674-1056/24/1/014207 Published: January 1, 2015Abstract:By using a reflective graphene oxide as saturable absorber, a diode-pumped passively mode-locked Yb3+:Sc2SiO5 (Yb:SSO) laser has been demonstrated for the first time. Without extra negative dispersion compensation, the minimum pulse duration of 1.7 ps with a repetition rate of 94 MHz was obtained at the central wavelength of 1062.6 nm. The average output power amounts to 355 mW under the absorbed pump power of 15 W. The maximum peak power of the mode-locking laser is up to 2.2 kW, and the single pulse energy is 3.8 nJ. ? 2015 Chinese Physical Society and IOP Publishing Ltd.Accession Number: 20150800536297 -
Record 172 of
Title:Towards low timing phase noise operation in fiber lasers mode locked by graphene oxide and carbon nanotubes at 1.5 μm
Author(s):Wu, Kan(1); Li, Xiaohui(2); Wang, Yonggang(3); Wang, Qi Jie(2); Shum, Perry Ping(2); Chen, Jianping(1)Source: Optics Express Volume: 23 Issue: 1 DOI: 10.1364/OE.23.000501 Published: January 12, 2015Abstract:We investigate the timing phase noise of fiber lasers mode locked by graphene oxide (GO) and carbon nanotubes (CNTs), respectively, integrated in a linear cavity fiber laser in the reflecting operation. Due to the shorter decay time of the GO and CNTs, weaker slow saturable absorber effects are expected and mode-locked lasers based on these two saturable absorbers exhibit low excess timing phase noise coupled from the laser intensity noise. Compared with a reference laser mode locked by semiconductor saturable absorber mirror (SESAM), GO based laser obtains a timing phase noise reduction of 7 dB at 1 kHz and a timing jitter reduction of 45% experimentally whereas CNTs based laser obtains a timing phase noise reduction of 3 dB and a timing jitter reduction of 29%. This finding suggests that saturable absorbers with short decay time have the potential for achieving mode locking operation with low timing phase noise, which is important for applications including frequency metrology, high-precision optical sampling, clock distribution and optical sensing. ? 2014 Optical Society of America.Accession Number: 20152901047204 -
Record 173 of
Title:Simultaneous bidirectional link selection in full duplex MIMO systems
Author(s):Zhou, Mingxin(1); Song, Lingyang(1); Li, Yonghui(2); Li, Xuelong(3)Source: IEEE Transactions on Wireless Communications Volume: 14 Issue: 7 DOI: 10.1109/TWC.2015.2416187 Published: July 1, 2015Abstract:In this paper, we consider a point to point full duplex (FD) MIMO communication system. We assume that each node is equipped with an arbitrary number of antennas which can be used for transmission or reception. With FD radios, bidirectional information exchange between two nodes can be achieved at the same time. In this paper, we design bidirectional link selection schemes by selecting a pair of transmit and receive antenna at both ends for communications in each direction to maximize the weighted sum rate or minimize the weighted sum symbol error rate (SER). The optimal selection schemes require exhaustive search, so they are highly complex. To tackle this problem, we propose a Serial-Max selection algorithm, which approaches the exhaustive search methods with much lower complexity. In the Serial-Max method, the antenna pairs with maximum 'obtainable SINR' at both ends are selected in a two-step serial way. The performance of the proposed Serial-Max method is analyzed, and the closed-form expressions of the average weighted sum rate and the weighted sum SER are derived. The analysis is validated by simulations. Both analytical and simulation results show that as the number of antennas increases, the Serial-Max method approaches the performance of the exhaustive-search schemes in terms of sum rate and sum SER. ? 2015 IEEE.Accession Number: 20152901038826 -
Record 174 of
Title:Super resolution ISAR imaging in receiver centered region area in bistatic radar
Author(s):Zhang, Long(1,2); Su, Tao(1); Liu, Zheng(1); He, Xiao-Hui(1,2); Duan, Yong-Qiang(3)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 3 DOI: 10.3788/gzxb20154403.0328002 Published: March 1, 2015Abstract:For the time-variant property of bistatic angles in Receiver Centered Region Area in bistatic radar system, it's difficult to obtain high resolution ISAR image of target in by using the conventional imaging methods. The signal model for bistatic ISAR was presented, then the time-variant property of the bistatic angles and its influence on range envelope and azimuth was analyzed. A Radon-TCDS-Relax super-resolution imaging method was brought up for eliminate the effect from high-order azimuth terms of target motion model in receiver centered areas. The chirp rate and its changing rate corresponding to high-order phase terms in cross range was estimated by the proposed method. Scatterers extracting and imaging were achieved by Radon-TCDS-RELAX and TCD-RID respectively. Accuracy analysis and the experimental results with real data both demonstrate the effectiveness of the proposed method. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20151600765014 -
Record 175 of
Title:Spatial-aware object-level saliency prediction by learning graphlet hierarchies
Author(s):Zhang, Luming(1); Xia, Yingjie(1,2); Ji, Rongrong(3); Li, Xuelong(4)Source: IEEE Transactions on Industrial Electronics Volume: 62 Issue: 2 DOI: 10.1109/TIE.2014.2336602 Published: February 1, 2015Abstract:To fill the semantic gap between the predictive power of computational saliency models and human behavior, this paper proposes to predict where people look at using spatial-aware object-level cues. While object-level saliency has been recently suggested by psychophysics experiments and shown effective with a few computational models, the spatial relationship between the objects has not yet been explored in this context. We in this work for the first time explicitly model such spatial relationship, as well as leveraging semantic information of an image to enhance object-level saliency modeling. The core computational module is a graphlet-based (i.e., graphlets are moderate-sized connected subgraphs) deep architecture, which hierarchically learns a saliency map from raw image pixels to object-level graphlets (oGLs) and further to spatial-level graphlets (sGLs). Eye tracking data are also used to leverage human experience in saliency prediction. Experimental results demonstrate that the proposed oGLs and sGLs well capture object-level and spatial-level cues relating to saliency, and the resulting saliency model performs competitively compared with the state-of-the-art. ? 2014 IEEE.Accession Number: 20150300433060 -
Record 176 of
Title:Numerical and Experimental Analysis of Sensitivity-Enhanced RI Sensor Based on Ex-TFG in Thin Cladding Fiber
Author(s):Yan, Zhijun(1,2); Sun, Zhongyuan(1); Zhou, Kaiming(1); Luo, Binbin(1,3); Li, Jianfeng(1,4); Wang, Hushan(2); Wang, Yishan(2); Zhao, Wei(2); Zhang, Lin(1)Source: Journal of Lightwave Technology Volume: 33 Issue: 14 DOI: 10.1109/JLT.2015.2422076 Published: July 15, 2015Abstract:We report a highly sensitive refractive index (RI) sensor in the aqueous solution, which is based on an 81°-tilted fiber grating structure inscribed into a thin cladding fiber with 40 μm cladding radius. The numerical analysis has indicated that the RI sensitivity of cladding resonance mode of the grating can be significantly enhanced with reducing cladding size. This has been proved by the experimental results as the RI sensitivities of TM and TE resonance peaks in the index region of 1.345 have been increased to 1180 nm/RIU and 1150 nm/RIU, respectively, from only 200 and 170 nm/RIU for the same grating structure inscribed in standard telecom fiber with 62.5-μm cladding radius. Although the temperature sensitivity has also increased, the change in temperature sensitivity is still insignificant in comparison with RI sensitivity enhancement. ? 1983-2012 IEEE.Accession Number: 20153001072350 -
Record 177 of
Title:Design of a multifunction astronomical CCD camera
Author(s):Yao, Dalei(1,2,3); Wen, Desheng(2); Xue, Jianru(1); Chen, Zhi(2); Wen, Yan(2); Jiang, Baotan(2); Xi, Jiangbo(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9631 Issue: DOI: 10.1117/12.2197105 Published: 2015Abstract:To satisfy the requirement of the astronomical observation, a novel timing sequence of frame transfer CCD is proposed. The multiple functions such as the adjustments of work pattern, exposure time and frame frequency are achieved. There are four work patterns: normal, standby, zero exposure and test. The adjustment of exposure time can set multiple exposure time according to the astronomical observation. The fame frequency can be adjusted when dark target is imaged and the maximum exposure time cannot satisfy the requirement. On the design of the video processing, offset correction and adjustment of multiple gains are proposed. Offset correction is used for eliminating the fixed pattern noise of CCD. Three gains pattern can improve the signal to noise ratio of astronomical observation. Finally, the images in different situations are collected and the system readout noise is calculated. The calculation results show that the designs in this paper are practicable. ? 2015 SPIE.Accession Number: 20154501514866 -
Record 178 of
Title:WS2 saturable absorber for dissipative soliton mode locking at 1.06 and 1.55 μm
Author(s):Mao, Dong(1,4); Zhang, Shengli(2,4); Wang, Yadong(1); Gan, Xuetao(1); Zhang, Wending(1); Mei, Ting(1); Wang, Yonggang(3); Wang, Yishan(3); Zeng, Haibo(2); Zhao, Jianlin(1)Source: Optics Express Volume: 23 Issue: 21 DOI: 10.1364/OE.23.027509 Published: October 19, 2015Abstract:Transition-metal dichalcogenides, such as tungsten disulfide (WS2) and molybdenium disulfide (MoS2), are highly anisotropic layered materials and have attracted growing interest from basic research to practical applications due to their exotic physical property that may complement graphene and other semiconductor materials. WS2 nanosheets are found to exhibit broadband nonlinear saturable absorption property, and saturable absorbers (SAs) are fabricated by depositing WS2 nanosheets on side-polished fibers. Attributing to the weak evanescent field and long interaction length, the WS2 nanosheets are not exposed to large optical intensity, which allows the SA to work at the high-power regime. The SAs are used to mode lock erbium- and ytterbium-doped fiber lasers with normal dispersion, producing trains of dissipative soliton at 1.55 and 1.06 μm respectively. Simulations show that the bandgap of WS2 nanosheets decreases from 1.18 to 0.02 and 0.65 eV by introducing W and S defects respectively, which may contribute to the broadband saturable absorption property of the WS2. ? 2015 Optical Society of America.Accession Number: 20160601907240 -
Record 179 of
Title:Learning to Rank for Blind Image Quality Assessment
Author(s):Gao, Fei(1); Tao, Dacheng(2); Gao, Xinbo(3); Li, Xuelong(4)Source: IEEE Transactions on Neural Networks and Learning Systems Volume: 26 Issue: 10 DOI: 10.1109/TNNLS.2014.2377181 Published: October 1, 2015Abstract:Blind image quality assessment (BIQA) aims to predict perceptual image quality scores without access to reference images. State-of-the-art BIQA methods typically require subjects to score a large number of images to train a robust model. However, subjective quality scores are imprecise, biased, and inconsistent, and it is challenging to obtain a large-scale database, or to extend existing databases, because of the inconvenience of collecting images, training the subjects, conducting subjective experiments, and realigning human quality evaluations. To combat these limitations, this paper explores and exploits preference image pairs (PIPs) such as the quality of image Iais better than that of image Ibfor training a robust BIQA model. The preference label, representing the relative quality of two images, is generally precise and consistent, and is not sensitive to image content, distortion type, or subject identity; such PIPs can be generated at a very low cost. The proposed BIQA method is one of learning to rank. We first formulate the problem of learning the mapping from the image features to the preference label as one of classification. In particular, we investigate the utilization of a multiple kernel learning algorithm based on group lasso to provide a solution. A simple but effective strategy to estimate perceptual image quality scores is then presented. Experiments show that the proposed BIQA method is highly effective and achieves a performance comparable with that of state-of-the-art BIQA algorithms. Moreover, the proposed method can be easily extended to new distortion categories. ? 2012 IEEE.Accession Number: 20154201387038 -
Record 180 of
Title:Research on remote fluorescent temperature measurement system
Author(s):Song, Wei(1); Li, Dong-Jian(2); Xie, Wei(1); Zhang, Wen-Song(2); Kou, Xiao-Kuo(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 1 DOI: 10.3788/gzxb20154401.0112003 Published: January 1, 2015Abstract:To realize the non-contact temperature monitoring of high voltage electrical equipment, a non-contact (0~1.5 m) fluorescence fiber temperature measurement system was designed. Using the relation between fluorescence and temperature of rare earth materials, temperature measurement was achieved by measuring the excited fluorescence lifetime of the fluorescent material which was attached on the object. The analysis indicates that the received light energy can be increased through adding a converging lens and a converging cone. In the experiment, the fluorescence intensity curve was obtained, and the temperature was aquired according to the relation of fluorescence lifetime and the temperature of the measured object. The measurement error is less than 1 ℃, ensuring its application in high-voltage environment. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20151100646880