2012
2012
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Record 277 of
Title:Dual-channel phase-shifting interferometry for microscopy with second wavelength assistance
Author(s):Zheng, Juanjuan(1,2); Yao, Baoli(1); Rupp, Romano A.(3); Ye, Tong(1); Gao, Peng(1); Min, Junwei(1); Guo, Rongli(1)Source: Chinese Optics Letters Volume: 10 Issue: 1 DOI: 10.3788/COL201210.010901 Published: January 2012Abstract:Dual-channel phase-shifting interferometry for simultaneous phase microscopy is presented. Red and blue light beams are used for microscope illumination. A 45° tilted beamsplitter replicates the object and reference waves in red light together with the object wave in blue light into two parallel beams. The two resulting quadrature phase-shifting interferograms in red light and the object waves in blue light are generated in the two channels. The two interferograms are recorded simultaneously by a color chargecoupled device (CCD) camera, and can be separated via RGB components of the recorded color patterns without crosstalk. As a result, the phase of tested specimen can be retrieved. The feasibility of the proposed method is demonstrated by test performed on a microscopic specimen. ? 2012 Chinese Optics Letters.Accession Number: 20120714767258 -
Record 278 of
Title:Control of ultrafast laser-induced bulk nanogratings in fused silica via pulse time envelopes
Author(s):Mauclair, C.(1); Zamfirescu, M.(2); Colombier, J.P.(1); Cheng, G.(1,3); Mishchik, K.(1); Audouard, E.(1); Stoian, R.(1)Source: Optics Express Volume: 20 Issue: 12 DOI: 10.1364/OE.20.012997 Published: June 4, 2012Abstract:Employing a method of in-situ control we propose an approach for the optimization of self-arranged nanogratings in bulk fused silica under the action of ultrashort laser pulses with programmable time envelopes. A parametric study of the influence of the pulse duration and temporal form asymmetries is given. Using the diffraction properties of the laser-triggered subwavelength patterns we monitor and regulate the period and the quality of the periodic nanoscale arrangement via the effective nonlinear excitation dose. Periodicity tuning on tens of nanometers can be achieved by pulse temporal variations, with a minimum around 0.7 ps at the chosen powers. Equally, strong sensitivity to pulse asymmetries is observed. The driving factor is related to increasing carrier densities due to nonlinear confinement and the development of extended nanoroughness domains upon multiple exposure, creating a pulse-dependent effective accumulation dose via a morpho-dimensional effect. The result may impact the associated optical functions. ? 2012 Optical Society of America.Accession Number: 20122915254971 -
Record 279 of
Title:Kinematical analysis of one-axis polisher - Acting on spherical mirror
Author(s):Xu, Liang(1); Ding, Jiao-Teng(1); Ma, Zhen(1); Chen, Qin-Fang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8416 Issue: DOI: 10.1117/12.975673 Published: 2012Abstract:A three-dimensional kinematic model of spherical mirror is developed by coordinate transformation theory. Based on the model and Preston equation, material removal rate for polishing with constant pressure can be obtained. Then the fitted parameters are determined for special process tools (pentagon tool and Uniform Removal Tool), Conclusions beneficial to glass polishing in practice are arrived. The simulate results can describe visually the material removal law of mirror under so many kinematic parameters. The work discussed above is of importance to polish flat mirror, spherical mirror and aspheric mirror with one-axis polisher. ? 2012 SPIE.Accession Number: 20131416168546 -
Record 280 of
Title:Learning optimal spatial filters by discriminant analysis for brain-computer-interface
Author(s):Pang, Yanwei(1); Yuan, Yuan(2); Wang, Kongqiao(3)Source: Neurocomputing Volume: 77 Issue: 1 DOI: 10.1016/j.neucom.2011.07.016 Published: 01 February 2012Abstract:Common Spatial Pattern (CSP) is one of the most widespread methods for Brain-Computer Interfaces (BCI), which is capable of enhancing the separability of the brain signals such as multi-channel electroencephalogram (EEG). CSP attempts to strengthen the separability by maximizing the variance of the spatially filtered signal of one class while minimizing it for another class. A straightforward way to improve the CSP is to employ the Fisher-Rao linear discriminant analysis (FLDA). But for the two-class scenario in BCI, FLDA merely result in as small as one filter. Experimental results have shown that the number of spatial filter is too small to achieve satisfying classification accuracy. Therefore, more than one filter is expected to get better performance. To deal with this difficulty, in this paper we propose to divide each class into many sub-classes (clusters) and formulate the problem in a re-designed graph embedding framework where the vertexes are cluster centers. We also reformulate the traditional FLDA in our graph embedding framework, which helps developing and understanding the proposed method. Experimental results demonstrate the advantages of the proposed method. ? 2011 Elsevier B.V.Accession Number: 20114614520926 -
Record 281 of
Title:Nonrigid structure-from-motion from 2-d images using markov chain monte carlo
Author(s):Zhou, Huiyu(1); Li, Xuelong(2); Sadka, Abdul H.(3)Source: IEEE Transactions on Multimedia Volume: 14 Issue: 1 DOI: 10.1109/TMM.2011.2170406 Published: February 2012Abstract:In this paper we present a new method for simultaneously determining 3-D shape and motion of a nonrigid object from uncalibrated 2-D images without assuming the distribution characteristics. A nonrigid motion can be treated as a combination of a rigid rotation and a nonrigid deformation. To seek accurate recovery of deformable structures, we estimate the probability distribution function of the corresponding features through random sampling, incorporating an established probabilistic model. The fitting between the observation and the projection of the estimated 3-D structure will be evaluated using a Markov chain Monte Carlo based expectation maximization algorithm. Applications of the proposed method to both synthetic and real image sequences are demonstrated with promising results. ? 2006 IEEE.Accession Number: 20120514724069 -
Record 282 of
Title:The implementation of remote digital video monitoring system based on ARM11
Author(s):Du, Shichang(1); Li, Bianxia(1)Source: 2012 IEEE 5th International Conference on Advanced Computational Intelligence, ICACI 2012 Volume: Issue: DOI: 10.1109/ICACI.2012.6462632 Published: 2012Abstract:This paper describes the design and implementation of a remote video monitoring system. The system adopts ARM11 as the main processor, and uses hard-coding to compress the video data with H.264. In the embedded environment of Linux, server adopts V4L2 interface technology, the latest H.264 video coding technology, and RTP/RTCP Real-Time Transport Protocol to complete video capture, encoding and transmission process. At the beginning of this paper it describes the necessity of the design of the system. And then it elaborates the realization methods of hardware and software, and makes necessary instructions of the choice of some methods. At the end of the paper, we tested the system and showed the test results. ? 2012 IEEE.Accession Number: 20131116105228 -
Record 283 of
Title:Design and optimize the supporting structure of large-diameter lightweight mirror
Author(s):Chai, WenYi(1); Xie, YongJie(1); Wang, Wei(1); Wu, MengYuan(1); Fan, XueWu(1)Source: Applied Mechanics and Materials Volume: 224 Issue: DOI: 10.4028/www.scientific.net/AMM.224.170 Published: 2012Abstract:This paper describe design and optimize of the lightweight primary mirror assemblies for the space telescope, aim at supporting structure of the primary mirror with an aperture of 530mm for the Cassegrain optical. We design three kinds of flexible support structure for the mirror, and numerical simulation analysis the accuracy of reflective shape for mirror assemblies on the ground test and in-orbit work environment, compare the results of analysis and optimize parameters of flexible structure, determine the final project and put it into production. The results show that the component should be aligned and tested in the same direction of the mirror optical axis and the gravity, the accuracy of reflective shape is PV<λ/25 and RMS<λ /125 (λ = 632.8nm), under the state ofΔ4°C temperature change, the RMS<λ/234 (λ = 632.8nm), the project meet design requirements of the optical system. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20125015804814 -
Record 284 of
Title:Spatial frequency multiplexing of fiber-optic interferometric refractive index sensors based on graded-index multimode fibers
Author(s):Liu, Li(1); Gong, Yuan(1,2); Wu, Yu(1); Zhao, Tian(1); Wu, Hui-Juan(1); Rao, Yun-Jiang(1)Source: Sensors (Switzerland) Volume: 12 Issue: 9 DOI: 10.3390/s120912377 Published: September 2012Abstract:Fiber-optic interferometric sensors based on graded-index multimode fibers have very high refractive-index sensitivity, as we previously demonstrated. In this paper, spatial-frequency multiplexing of this type of fiber-optic refractive index sensors is investigated. It is estimated that multiplexing of more than 10 such sensors is possible. In the multiplexing scheme, one of the sensors is used to investigate the refractive index and temperature responses. The fast Fourier transform (FFT) of the combined reflective spectra is analyzed. The intensity of the FFT spectra is linearly related with the refractive index and is not sensitive to the temperature. ? 2012 by the authors; licensee MDPI, Basel, Switzerland.Accession Number: 20131816281290 -
Record 285 of
Title:Polarization multiplexing, angle multiplexing and circumrotation multiplexing holographic recording experiments with 3-indoly-benzylfulgimide/ PMMA film
Author(s):Zong, Zhengyue(1); Menke, Neimule(1,2); Yao, Baoli(2); Wang, Yingli(2); Chen, Yi(3)Source: Applied Mechanics and Materials Volume: 130-134 Issue: DOI: 10.4028/www.scientific.net/AMM.130-134.2035 Published: 2012Abstract:Fulgide is well-known as a thermally irreversible organic photochromic compound. The fulgide films can be applied as recording materials in ordinary holography and polarization holography, which were respectively based on the photochromic and photoinduced anisotropy properties. In this report, different kinds of multiplexing holographic storage, like angle multiplexing, circumrotation multiplexing and polarization multiplexing are realized in a 3-indoly-benzylfulgimide/ PMMA film for the first time, where 5 images, 18 images and 2 images are stored at the same position of the film, and diffracted without crosstalk with each other. It is proved that 3-indoly-benzylfulgimide film has spatial resolution of 6300lines/mm, sensitivity of 2.89 × 10 -3cm2/mJ at 632.8nm on the polarization direction of the exciting beam, fatigue resistance of 70 times, thermal stability of 14 months and has advantages like low cost, easy to used, rewritable, long life time at room temperature for both states, and high signal to noise ratio. Overall, 3-indoly-benzylfulgimide is a better rewritable holographic storage medium, but the fatigue resistance and thermal stability should be improved. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20114714534681 -
Record 286 of
Title:Modular remote-controllable anisotropic focusing streak camera
Author(s):Liu, Jie(1,3); Ding, Yongkun(2); Tian, Jinshou(1); Liu, Shenye(2); Cao, Xibin(1); Wen, Wenlong(1); Hu, Xin(2); Xu, Xiangyan(1); Wang, Junfeng(1); Dong, Gaiyun(1); Liu, Hulin(1); Wang, Chao(1); Zhang, Tie(1)Source: Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams Volume: 24 Issue: 10 DOI: 10.3788/HPLPB20122410.2405 Published: October 2012Abstract:Anisotropic focus electrodes and electric quadrupole lenses have been used to make a novel streak tube, whose physical temporal dispersion and edge spatial resolution are 0.38 ps and 56 lp/mm respectively. A modular remote-controllable system has been designed to control high voltage supply, environmental monitoring, deflection voltage switch and camera work mode. The Nd:YLF 8 ps pulsed laser was used to calibrate the performance index of the streak camera. The streak static and dynamic spatial resolution are 35 lp/mm and 25 lp/mm respectively. The dynamic range more than 950:1 and time resolution of 8 ps are reached. Furthermore, the magnifications in slit and scanning direction can be adjusted respectively. When the camera is coupled with KB microscope, it is convenient to select amplification needed.Accession Number: 20124415631139 -
Record 287 of
Title:Video super-resolution with 3D adaptive normalized convolution
Author(s):Zhang, Kaibing(1); Mu, Guangwu(1); Yuan, Yuan(2); Gao, Xinbo(1); Tao, Dacheng(3)Source: Neurocomputing Volume: 94 Issue: DOI: 10.1016/j.neucom.2012.03.012 Published: October 1, 2012Abstract:The classic multi-image-based super-resolution (SR) methods typically take global motion pattern to produce one or multiple high-resolution (HR) versions from a set of low-resolution (LR) images. However, due to the influence of aliasing and noise, it is difficult to obtain highly accurate registration with sub-pixel accuracy. Moreover, in practical applications, the global motion pattern is rarely found in the real LR inputs. In this paper, to surmount or at least reduce the aforementioned problems, we develop a novel SR framework for video sequence by extending the traditional 2-dimentional (2D) normalized convolution (NC) to 3-dimentional (3D) case. In the proposed framework, to bypass explicit motion estimation, we estimate a target pixel by taking a weighted average of pixels from its neighborhood. We further up-scale the input video sequence in temporal dimension based on the extended 3D NC and hence more video frames can be generated. Fundamental experiments demonstrate the effectiveness of the proposed SR framework both quantitatively and perceptually. ? 2012 Elsevier B.V.Accession Number: 20122815227441 -
Record 288 of
Title:Slow-light in photonic crystal waveguides/fibers: Dispersion tailoring schemes for obtaining a high group index with wide band and low GVD
Author(s):Ren, Liyong(1); Liang, Jian(1); Liu, Yu(1); Ju, Haijuan(1); Yun, Maojin(2); Ma, Chengju(1); Han, Xu(1); Lin, Xiao(1); Tomita, Yasuo(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8273 Issue: DOI: 10.1117/12.914460 Published: 2012Abstract:Phenomenon of slow light has long been a hot research topic due to its promising and potential applications in communication networks, signal processing, optical sensors and nonlinear interactions. Particularly, photonic crystal devices, being capable of supporting slow-light propagation, are much attractive owing to its room-temperature operation and tunable dispersion features. Among them, photonic crystal waveguides (PCWs) are specially used in compact devices, while photonic band-gap fibers (PBGFs) are usually used in short-distance propagation and high sensitive interferometers. In this paper, dispersion tailoring schemes for obtaining a high group index with the wide band and low group velocity dispersion (GVD) are reviewed in both PCWs and PBGFs. For the same purpose, we propose schemes for the slow-pulse propagation in PCWs based on the air-hole shifting method and in PBGFs based on the microfluid infiltration method, respectively. Simulation results using 2D plane wave expansion method and finite-difference timedomain (FDTD) method are given. Pulse distortion and design optimization are also discussed in some detail with the consideration of the practical fabrication errors. Slow-light pulse propagation in photonic crystal fiber is also demonstrated in the experiment based on stimulated Brillouin scattering. ? 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).Accession Number: 20120914826333