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Lensless Vanderlugt optical correlator using two phase-only spatial light modulators(Invited Paper) 被引量:2
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作者 Norihiro Fukuchi Takashi Inoue +1 位作者 Haruyoshi Toyoda Tsutomu Hara 《Chinese Optics Letters》 SCIE EI CAS CSCD 2009年第12期1131-1133,共3页
A lensless Vanderlugt optical correlator using two phase-only spatial light modulators (SLMs) is proposed. The SLMs are used for displaying input and filter patterns respectively. The SLMs are also used as programma... A lensless Vanderlugt optical correlator using two phase-only spatial light modulators (SLMs) is proposed. The SLMs are used for displaying input and filter patterns respectively. The SLMs are also used as programmable lenses in order to realize the lensless construction. This lensless system is simple and its alignment adjustment is easy. The performance of the SLMs as programmable lenses is also described. 展开更多
关键词 SLM Invited Paper FLPs Lensless Vanderlugt optical correlator using two phase-only spatial light modulators
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Mountain Glacier Flow Velocities Analyzed from Satellite Optical Images
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作者 Lei Huang Zhen Li 《Research in Cold and Arid Regions》 2010年第1期59-66,共8页
Mountain glaciers are sensitive to environment. It is important to acquire ice flow velocities over time for glacier research and hazard forecast. For this paper, cross-correlating of optical images is used to monitor... Mountain glaciers are sensitive to environment. It is important to acquire ice flow velocities over time for glacier research and hazard forecast. For this paper, cross-correlating of optical images is used to monitor ice flow velocities, and an improvement, which is called "moving grid," is made to this method. For this research, two remote-sensing images in a certain glacier area, dur-ing different times are selected. The first image is divided into grids, and we calculated the correlation coefficient of each window in the grid with the window on the second image. The window with the highest correlation coefficient is considered the counter-part one on the first image. The displacement of the two corresponding windows is the movement of the glacier, and it is used to calculate glacier surface velocity. Compared to the traditional way of dividing an image with ascertain grid, this method uses small steps to move the grid from one location to another adjacent location until the whole glacier area is covered in the image, thus in-creasing corresponding point density. We selected a glacier in the Tianshan Mountains for this experiment and used two re-mote-sensing images with a 10-year interval to determine this method. 展开更多
关键词 glacier flow satellite optical image correlation grid
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Photon statistics of pulse-pumped four-wave mixing in fiber with weak signal injection 被引量:1
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作者 刘楠楠 刘宇宏 +1 位作者 李嘉敏 李小英 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第7期229-233,共5页
We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental re... We study the photon statistics of pulse-pumped four-wave mixing in fibers with weak coherent signal injection by measuring the intensity correlation functions of individual signal and idler fields. The experimental results show that the intensity correlation function of individual signal(idler) field g_(s(i))^(2) decreases with the intensity of signal injection. After applying narrow band filter in signal(idler) band, the value of g_(s(i))^(2) decreases from 1.9 ± 0.02(1.9 ± 0.02) to 1.03 ± 0.02(1.05 ± 0.02) when the intensity of signal injection varies from 0 to 120 photons/pulse. The results indicate that the photon statistics changes from Bose–Einstein distribution to Poisson distribution. We calculate the intensity correlation functions by using the multi-mode theory of four-wave mixing in fibers. The theoretical curves well fit the experimental results.Our investigation will be useful for mitigating the crosstalk between quantum and classical channels in a dense wavelength division multiplexing network. 展开更多
关键词 photon statistics four-wave mixing intensity correlation function fiber optics
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Contrast Enhancement of Radiographs Using Shift Invariant Wavelet Transform
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作者 Yang, Yan Zhang, Dong 《Wuhan University Journal of Natural Sciences》 EI CAS 2000年第1期59-62,共4页
A novel approach using shift invariant wavelet transform is presented for the contrast enhancement of radiographs. By exploiting cross-scale correlation among wavelet coefficients, edge information of radiographic ima... A novel approach using shift invariant wavelet transform is presented for the contrast enhancement of radiographs. By exploiting cross-scale correlation among wavelet coefficients, edge information of radiographic images is extracted and protected, while noise is smoothed out in the wavelet domain. Radiographs are then reconstructed from the transform coefficients modified at multi-scales by nonlinear enhancement operator. The method can achieve effectively contrast enhancement and edge-preserved denoising simultaneously, yet it is capable of giving visually distinct images and offering considerable benefits in medical diagnosis. 展开更多
关键词 Edge detection Image analysis Image enhancement optical correlation Wavelet transforms
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Improved digital processing method used for image motion measurement based on hybrid opto-digital joint transform correlator 被引量:5
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作者 易红伟 赵惠 +1 位作者 李英才 汶德胜 《Chinese Optics Letters》 SCIE EI CAS CSCD 2010年第10期989-992,共4页
Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and th... Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The local cross-correlation image can be directly obtained by adopting a local Fourier transform operator. After the pixel-level location of cross-correlation peak is initially obtained, the up-sampling technique is introduced to relocate the peak in even higher accuracy. With signal-to-noise ratio ≥ 20 dB, up-sampling factor k ≥ 10 and the maximum image shift ≤ 60 pixels, the root-mean-square error of motion measurement accuracy can be controlled below 0.05 pixels. 展开更多
关键词 Fourier transforms MEASUREMENTS optical correlation PROCESSING Signal to noise ratio
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Separation and insertion of optical bit-serial label in optical packet switching 被引量:1
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作者 凌云 邱昆 郑勉 《Chinese Optics Letters》 SCIE EI CAS CSCD 2006年第3期138-140,共3页
The bipolar phase-shift-keying (BPSK) optical orthogonal codes (OOCs) are inserted into the optical packet format of bit-serial label. The ultra-fast separation of the label and payload is performed through the au... The bipolar phase-shift-keying (BPSK) optical orthogonal codes (OOCs) are inserted into the optical packet format of bit-serial label. The ultra-fast separation of the label and payload is performed through the auto-correlation pulses indicating the time position at whicl, the optical switch changes the state. The insertion of the new label can also be realized by detecting the auto-correlatiou pulse at the line rate. Especially, the scheme can be adapted to the asynchronous separation and insertion and realize the variable-length packet switching. The results of simulation verify the fea.sibility of the scheme. 展开更多
关键词 Labels optical correlation Phase shift keying SEPARATION Simulation
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Quantum optical correlation through metamaterials 被引量:1
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作者 Yun-Xia Dong Xiao-Hua Cui 《Frontiers in Biology》 CAS CSCD 2012年第5期509-513,共5页
Based on the quantization scheme of the radiation fields in the dispersive and absorptive magnetic media, the normally ordered correlation functions of the outgoing field through a metamaterial plate are obtained. The... Based on the quantization scheme of the radiation fields in the dispersive and absorptive magnetic media, the normally ordered correlation functions of the outgoing field through a metamaterial plate are obtained. Then the relative photon-number densities of the transmitted field, the reflected field and the absorbed field are gotten through the correlation functions. Furthermore, the contributions of the relative permittivity and permeability of the metamaterials to the transmission are analyzed. Our results show that the permittivity and permeability reinforce the transmission for frequencies that are big compared with the magnetic resonance frequency. 展开更多
关键词 METAMATERIALS magnetic resonance quantum optical correlation
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Research on optical biosensor with up-converting phosphor marker
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作者 赵永凯 周蕾 +7 位作者 王静 黄立华 闫中强 黄惠杰 杨瑞馥 刘蕾 任冰强 王向朝 《Chinese Optics Letters》 SCIE EI CAS CSCD 2006年第8期464-466,共3页
An optical biosensor with up-converting phosphor (UCP) marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detectin... An optical biosensor with up-converting phosphor (UCP) marker is developed for the sensitive rapid immunoassay to the specific biomolecule. UCP can emit visible light when excited by infrared light. Through detecting and analyzing the content of UCP particles on the test strip after immunoreaction, the concentration of target analyte in the sample can be obtained. The detection sensitivity to plague IgG is better than 5 ng/ml; to plague FI-Ab is better than 100 pg/ml; to plague Yersinia pestis cell is better than 3 ×10^4 CFU/ml. Good linear response characteristics and an excellent correlation (R^2 ≥ 0.95) have been verified by quantitative detection results. In the practical application, detection results to 167 analytic samples have an excellent consistency with those obtained by reverse hemagglutination test. The up-converting phosphor technology (UPT) based biosensor has stable, reliable, and sensitive performances. It can meet the need of various bioassay applications. 展开更多
关键词 BIOASSAY Biosensors optical correlation PHOSPHORS
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Normalized intensity correlation function of single-mode laser system driven by colored cross-correlation noises
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作者 王兵 吴秀清 《Chinese Optics Letters》 SCIE EI CAS CSCD 2008年第4期288-290,共3页
Considering a single-mode laser system with cross-correlated additive colored noise and multiplicative colored noise, we study the effects of correlation among noises on the normalized intensity correlation function C... Considering a single-mode laser system with cross-correlated additive colored noise and multiplicative colored noise, we study the effects of correlation among noises on the normalized intensity correlation function C(s). C(s) is derived by means of the projection operator method. The effects of the selfcorrelation time T1 of the additive colored noise, T2 of the multiplicative colored noise, and the effect of the cross-correlation time TO between the two noises on C(s) are discussed by numerical calculation. For the case of positive correlation (λ 〉 0), it is found that when a0 〉 0 the normalized intensity correlation function C(s) increases with the increase of T0 or T2, and with value of T0 or T2 becoming larger, C(s) comes to saturation. With increasing the self-correlation time T1 of the additive noise, a minimum and a maximum will appear on curve of C(s) as a0 〉 0. If a0 〈 0, C(s) decreases with the increase of T0, T1, and T2. 展开更多
关键词 Additive noise Calculations Laser modes Mathematical operators Nonlinear optics optical correlation
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Non-linearly weighted fuzzy correlation for color-image retrieval
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作者 母国光 翟宏琛 张思远 《Chinese Optics Letters》 SCIE EI CAS CSCD 2003年第10期583-584,共2页
An algorithm with non-linear weight factors in the summation process for fuzzy correlation of color histograms is presented, in which non-linear weights are assigned to some characteristic colors of interest. Experime... An algorithm with non-linear weight factors in the summation process for fuzzy correlation of color histograms is presented, in which non-linear weights are assigned to some characteristic colors of interest. Experimental results show that this can improve the retrieval of color images with partial aberrations or with local color characters. 展开更多
关键词 Fuzzy sets Image processing optical correlation
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Rotation invariant pattern recognition with a volume holographic wavelet correlation processor
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作者 檀文钊 薛庆增 +1 位作者 严瑛白 金国藩 《Chinese Optics Letters》 SCIE EI CAS CSCD 2003年第2期74-77,共4页
A volume holographic wavelet correlation processor for performing rotation invariant pattern recognition is suggested. It uses wavelet transform to get the digital edge extraction of the original object and a single c... A volume holographic wavelet correlation processor for performing rotation invariant pattern recognition is suggested. It uses wavelet transform to get the digital edge extraction of the original object and a single circular harmonic component is used as the matched filter to get good rotation invariance. The new filter used in this method is called wavelet circular harmonic component filter (WCHCF). Simulation results validate the theory and the experiment to recognize human faces with any rotation angle shows the utility of the newly proposed method. 展开更多
关键词 optical correlation Wavelet transforms
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