2014
2014
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Record 157 of
Title:Design and experimental demonstration of variable curvature mirror having a large saggitus variation
Author(s):Xie, Xiaopeng(1); Zhao, Hui(2); Ren, Guorui(2); Wei, Jingxuan(3); Menke, Neimule(4)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9272 Issue: DOI: 10.1117/12.2070987 Published: 2014Abstract:Variable curvature mirror (VCM) is a simplified active optical component being capable of changing its curvature radius. Curvature radius variation within a wide range requires that the VCM should be able to generate a large saggitus variation. Besides that, the surface form accuracy should be maintained above a reasonable level. In this paper, a piezoelectric actuation based prototype VCM is designed, constructed and experimentally tested. The thickness of the K9 plane mirror is only 3mm over the full aperture of 100mm. Six piezoelectric actuators are fixed into a base plate and the head of each actuator is connected to an annular ring through the screw thread. With such a structure, the force provided by each actuator can be transformed to the mirror backside through this annular ring. With each actuator generating the same force, the curvature radius can be changed in a uniform way. At the mean time, the surface form accuracy could be adjusted one point by point to compensation asymmetric modes as well. Mathematical analysis and FEA (finite element analysis) are used together to demonstrate the theoretical correctness. Besides that, the prototype VCM is successfully constructed and experiments have been carried out to give a quantitative assessment on the saggitus variation.. ? 2014 SPIE.Accession Number: 20150700533029 -
Record 158 of
Title:Learning regularized LDA by clustering
Author(s):Pang, Yanwei(1); Wang, Shuang(1); Yuan, Yuan(2)Source: IEEE Transactions on Neural Networks and Learning Systems Volume: 25 Issue: 12 DOI: 10.1109/TNNLS.2014.2306844 Published: December 1, 2014Abstract:As a supervised dimensionality reduction technique, linear discriminant analysis has a serious overfitting problem when the number of training samples per class is small. The main reason is that the between- and within-class scatter matrices computed from the limited number of training samples deviate greatly from the underlying ones. To overcome the problem without increasing the number of training samples, we propose making use of the structure of the given training data to regularize the between- and within-class scatter matrices by between- and within-cluster scatter matrices, respectively, and simultaneously. The within- and between-cluster matrices are computed from unsupervised clustered data. The within-cluster scatter matrix contributes to encoding the possible variations in intraclasses and the between-cluster scatter matrix is useful for separating extra classes. The contributions are inversely proportional to the number of training samples per class. The advantages of the proposed method become more remarkable as the number of training samples per class decreases. Experimental results on the AR and Feret face databases demonstrate the effectiveness of the proposed method. ? 2012 IEEE.Accession Number: 20144900288874 -
Record 159 of
Title:Transport properties of random media composed of core-shell spheres
Author(s):Xu, Yuchen(1); Zhang, Hao(1,2); Zhang, Xiangchao(1); Shen, Yongqiang(1); Zhu, Heyuan(1); Lei, Ming(2); Xu, Min(1)Source: Applied Physics A: Materials Science and Processing Volume: 114 Issue: 4 DOI: 10.1007/s00339-013-7862-5 Published: March 2014Abstract:With the energy-density coherent potential approximation method, a series of calculations concerning the contribution from the morphology and dispersion of random media composed of core-shell spheres on the transport properties of random media are conducted in terms of the scattering-cross-section efficiency factor, mean free path, velocity of electromagnetic energy, and diffusion coefficient. It is found that the core layer introduces more complicated resonant modes which lead to diverse possibilities to sharply decrease the transport of light within random media. ? 2013 Springer-Verlag Berlin Heidelberg.Accession Number: 20141117441906 -
Record 160 of
Title:Weakly supervised multi-graph learning for robust image reranking
Author(s):Deng, Cheng(1); Ji, Rongrong(2); Tao, Dacheng(3); Gao, Xinbo(1); Li, Xuelong(4)Source: IEEE Transactions on Multimedia Volume: 16 Issue: 3 DOI: 10.1109/TMM.2014.2298841 Published: April 2014Abstract:Visual reranking has been widely deployed to refine the traditional text-based image retrieval. Its current trend is to combine the retrieval results from various visual features to boost reranking precision and scalability. And its prominent challenge is how to effectively exploit the complementary property of different features. Another significant issue raises from the noisy instances, from manual or automatic labels, which makes the exploration of such complementary property difficult. This paper proposes a novel image reranking by introducing a new Co-Regularized Multi-Graph Learning (Co-RMGL) framework, in which intra-graph and inter-graph constraints are integrated to simultaneously encode the similarity in a single graph and the consistency across multiple graphs. To deal with the noisy instances, weakly supervised learning via co-occurred visual attribute is utilized to select a set of graph anchors to guide multiple graphs alignment and fusion, and to filter out those pseudo labeling instances to highlight the strength of individual features. After that, a learned edge weighting matrix from a fused graph is used to reorder the retrieval results. We evaluate our approach on four popular image retrieval datasets and demonstrate a significant improvement over state-of-the-art methods. ? 2014 IEEE.Accession Number: 20141417538556 -
Record 161 of
Title:Measurements of the concentration of atmospheric CO2 based on OP/FTIR method and infrared reflecting scanning fourier transform spectrometry
Author(s):Wei, Ru-Yi(1); Zhou, Jin-Song(2); Zhang, Xue-Min(1,3); Yu, Tao(1,3); Gao, Xiao-Hui(1); Ren, Xiao-Qiang(1)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 34 Issue: 11 DOI: 10.3964/j.issn.1000-0593(2014)11-2978-06 Published: November 1, 2014Abstract:The present paper describes the observations and measurements of the infrared absorption spectra of CO2 on the Earth's surface with OP/FTIR method by employing a mid-infrared reflecting scanning Fourier transform spectrometry, which are the first results produced by the first prototype in China developed by the team of authors. This reflecting scanning Fourier transform spectrometry works in the spectral range 2100~3150 cm-1 with a spectral resolution of 2 cm-1. Method to measure the atmospheric molecules was described and mathematical proof and quantitative algorithms to retrieve molecular concentration were established. The related models were performed both by a direct method based on the Beer-Lambert Law and by a simulating-fitting method based on HITRAN database and the instrument functions. Concentrations of CO2 were retrieved by the two models. The results of observation and modeling analyses indicate that the concentrations have a distribution of 300~370 ppm, and show tendency that going with the variation of the environment they first decrease slowly and then increase rapidly during the observation period, and reached low points in the afternoon and during the sunset. The concentrations with measuring times retrieved by the direct method and by the simulating-fitting method agree with each other very well, with the correlation of all the data is up to 99.79%, and the relative error is no more than 2.00%. The precision for retrieving is relatively high. The results of this paper demonstrate that, in the field of detecting atmospheric compositions, OP/FTIR method performed by the Infrared reflecting scanning Fourier transform spectrometry is a feasible and effective technical approach, and either the direct method or the simulating-fitting method is capable of retrieving concentrations with high precision.Accession Number: 20144700222111 -
Record 162 of
Title:Flowing on riemannian manifold: Domain adaptation by shifting covariance
Author(s):Cui, Zhen(1,2); Li, Wen(3); Xu, Dong(3); Shan, Shiguang(2); Chen, Xilin(2); Li, Xuelong(4)Source: IEEE Transactions on Cybernetics Volume: 44 Issue: 12 DOI: 10.1109/TCYB.2014.2305701 Published: December 1, 2014Abstract:Domain adaptation has shown promising results in computer vision applications. In this paper, we propose a new unsupervised domain adaptation method called domain adaptation by shifting covariance (DASC) for object recognition without requiring any labeled samples from the target domain. By characterizing samples from each domain as one covariance matrix, the source and target domain are represented into two distinct points residing on a Riemannian manifold. Along the geodesic constructed from the two points, we then interpolate some intermediate points (i.e., covariance matrices), which are used to bridge the two domains. By utilizing the principal components of each covariance matrix, samples from each domain are further projected into intermediate feature spaces, which finally leads to domain-invariant features after the concatenation of these features from intermediate points. In the multiple source domain adaptation task, we also need to effectively integrate different types of features between each pair of source and target domains. We additionally propose an SVM based method to simultaneously learn the optimal target classifier as well as the optimal weights for different source domains. Extensive experiments demonstrate the effectiveness of our method for both single source and multiple source domain adaptation tasks. ? 2014 IEEE.Accession Number: 20144800255196 -
Record 163 of
Title:Weak signal detection method in a stronger noise background
Author(s):Wang, Jun(1); Bai, Jian Ming(2)Source: Applied Mechanics and Materials Volume: 568-570 Issue: DOI: 10.4028/www.scientific.net/AMM.568-570.260 Published: 2014Abstract:When we use the laser auto collimation theodolite to measure the azimuth error angle of air target, the strong noise background reduces the spot imaging quality and seriously influences the measuring angle ability of the theodolite. In order to solve the problem, a photoelectric detection system used to detect the weak signal is designed based the correlation detection principle and the principle of correlation detection technology is introduced. We use Simulink software presenting a simulation to the detection system and do a feasibility analysis. Finally, it's proved that the photoelectric detection system could suppress the strong noise background, improve the SNR greatly and detect the weak signal effectively. ? (2014) Trans Tech Publications, Switzerland.Accession Number: 20142717908354 -
Record 164 of
Title:The recent development of fiber-optic chemical sensor
Author(s):Wang, Jian(1,2,3); Wei, Jian-Ping(3); Yang, Bo(4); Gao, Zhi-Yang(4); Zhang, Li-Wei(1); Yang, Xue-Feng(1)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 34 Issue: 8 DOI: 10.3964/j.issn.1000-0593(2014)08-2035-05 Published: August 2014Abstract:The present article provides a brief review of recent research on fiber-optic chemical sensor technology and the future development trends. Especially, fiber-optic pH chemicl sensor, fiber-optic ion chemicl sensor, and fiber-optic gas chemical sensor are introducded respectively. Sensing film preparation methods such as chemical bonding method and sol-gel method were briefly reviewed. The emergence of new type fiber-microstructured optical fiber opened up a new development direction for fiber-optic chemical sensor. Because of its large inner surface area, flexible design of structure, having internal sensing places in fibers, it has rapidly become an important development direction and research focus of the fiber-optic chemical sensors. The fiber-optic chemical sensor derived from microstructured optical fiber is also discussed in detail. Finally, we look to the future of the fiber-optic chemical sensor.Accession Number: 20143218048387 -
Record 165 of
Title:Adaptive nonuniformity correction for IRFPA based on Bayesian estimation
Author(s):Leng, Hanbing(1); Xie, Qingsheng(1); Liu, Wei(1); Yi, Bo(1); Tang, Linao(1); Zhang, Jian(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 34 Issue: 9 DOI: 10.3788/AOS201434.0910001 Published: September 10, 2014Abstract:After long time working, the response characteristics of infrared focal plane array (IRFPA) often drift slowly, and the image quality always degrades. Aiming at the problem, the characteristic of residual noise after two point correction (TPC) is analyzed. An adaptive non-uniformity correction algorithm is proposed based on the TPC algorithm. The images after TPC is decomposed by wavelet, and the Bayesian threshold is used to estimate signal and noise variance point by point, the residual nonuniformity noise is calculated and removed. Experimental results show that the proposed algorithm can remove the residual nonuniformity noise effectively and avoids the image degradation caused by the response drift of IRFPA.Accession Number: 20144100087877 -
Record 166 of
Title:Piecewise linear response based on CMV4000 image sensor
Author(s):Meng, Yang Yang(1); Hu, Xiao Dong(1); Yang, Dong Lai(1)Source: Applied Mechanics and Materials Volume: 568-570 Issue: DOI: 10.4028/www.scientific.net/AMM.568-570.568 Published: 2014Abstract:With high speed CMOS image sensor CMV4000 produced by CMOSIS company as the object, after the thorough analysis of the piecewise linear response principle and how to extend the dynamic range, using piecewise linear response extends the dynamic range of CMV4000 image sensor. The ideas and methods of using the finite state machine designs piecewise linear response sequence are given, and the function simulation is done for the sequence in the Quartus II 9.0 environment using the Verilog HDL hardware description language. Through the analysis of simulation results, it can satisfy the demands of piecewise linear response sequence. The method is simple and feasible, and can improve the optical dynamic range of CMV4000 image sensor. ? (2014) Trans Tech Publications, Switzerland.Accession Number: 20142717908415 -
Record 167 of
Title:Feature learning for image classification via multiobjective genetic programming
Author(s):Shao, Ling(1,2); Liu, Li(2); Li, Xuelong(3)Source: IEEE Transactions on Neural Networks and Learning Systems Volume: 25 Issue: 7 DOI: 10.1109/TNNLS.2013.2293418 Published: July 2014Abstract:Feature extraction is the first and most critical step in image classification. Most existing image classification methods use hand-crafted features, which are not adaptive for different image domains. In this paper, we develop an evolutionary learning methodology to automatically generate domain-adaptive global feature descriptors for image classification using multiobjective genetic programming (MOGP). In our architecture, a set of primitive 2-D operators are randomly combined to construct feature descriptors through the MOGP evolving and then evaluated by two objective fitness criteria, i.e., the classification error and the tree complexity. After the entire evolution procedure finishes, the best-so-far solution selected by the MOGP is regarded as the (near-)optimal feature descriptor obtained. To evaluate its performance, the proposed approach is systematically tested on the Caltech-101, the MIT urban and nature scene, the CMU PIE, and Jochen Triesch Static Hand Posture II data sets, respectively. Experimental results verify that our method significantly outperforms many state-of-the-art hand-designed features and two feature learning techniques in terms of classification accuracy. ? 2013 IEEE.Accession Number: 20142717881461 -
Record 168 of
Title:Distributed real-time networked control architecture for suppressing wind load deformation of Fourier telescope
Author(s):Cheng, Zhiyuan(1); Ma, Caiwen(1)Source: Proceedings - 2014 6th International Conference on Intelligent Human-Machine Systems and Cybernetics, IHMSC 2014 Volume: 2 Issue: DOI: 10.1109/IHMSC.2014.189 Published: September 25, 2014Abstract:To advance optical profile accuracy of high-resolution imaging Fourier telescope and improve the real-time of profile error suppressing, the paper proposed a novel real-time networked control scheme integrated Ether CAT(Ethernet for control Automation Technology) field bus with PC-based control model. Based on the high speed transmission principle of EtherCAT field bus it improves the real-time of surface error suppressing induced by wind load and meets the requirements of high resolution imaging, Then it makes good use of powerful clustering control, the open architecture of PC controller to solve cluster control problem of mass distributed drivers in large telescope. The results show that EtherCAT networked control solution has advantages of highest real-time, flexible network control structure, powerful clustering control ability. It can meet the real-time requirement of profile error suppressing caused by wind load in Large Fourier telescope. ? 2014 IEEE.Accession Number: 20144600203470