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作者： D.B. Dunn Jiangang Xia Ting-Chung Poon Optical Image Processing Laboratory The Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University VA USA

We employ the transfer function approach to analyze the effects of the sound wave on the image to be processed in an acousto-optic image processing system. Theoretical and experimental results are provided for image e... 详细信息

关键词： image processing Transfer functions Lenses optical films Fourier transforms Equations image analysis Acoustic diffraction Laboratories USA Councils

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High frequency noise reduction using an acousto-optic cell

High frequency noise reduction using an acousto-optic cell

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Southeastern Symposium on System Theory

作者： D.B. Dunn Jiangang Xia Ting-Chung Poon Optical Image Processing Laboratory The Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University VA USA Virginia Polytechnic Institute and State University Blacksburg VA US Bradley Dept. of Electr. Eng. Virginia Polytech. Inst. & State Univ. Blacksburg VA USA

We present a novel and simple optical image processing system for high frequency noise reduction. The system consists of a single imaging lens and an acousto-optic modulator. image edge enhancement is achieved by Brag... 详细信息

关键词： Frequency Noise reduction optical scattering optical modulation Transfer functions optical noise image processing Lenses Light scattering optical imaging

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Detection of the complex amplitude distribution of a kinoform using an iterative Fourier-transform algorithm

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS 1996年第1期79卷 11-21页

作者： Akahori, H Faculty of Engineering Kanagawa Institute of Technology Atsugi Japan 243-02 Graduated in 1963 from the Department of Electrical Engineering Tokyo Institute of Technology and joined the Electrotechnical Laboratory of the Ministry of International Trade and Industry. Later he obtained a Dr. of Eng. degree. In 1987 he became a Professor in the Department of Information and Computer Sciences Kanagawa Institute of Technology. He has been engaged in research on optical information processing and digital holography.

This paper presents a method for recovering, by using the iterative Fourier-transform algorithm, the complex amplitude transmittance of a recorded one-dimensional Fourier transform-type kinoform. A method for estimating the phase-recording characteristic of the kinoform fabrication system by comparing the retrieved phase with the theoretical phase is also presented. The spatial variations of both the magnitude and phase inside each of the kinoform cells were evaluated to improve estimation of the phase-recording characteristic. The initial estimate of the kinoform phase given to the algorithm was derived using the knowledge that the recorded phase is an approximation of the phase to be recorded. The relationship between the shift of the central sampling point of the Fourier image from the optical axis and the retrieved phase of the kinoform is investigated;a kinoform phase pattern with a structure suitable for indirectly detecting the shift is then proposed. In an experiment using a kinoform fabrication system including a photographic process, the recorded phase distribution is retrieved at five sampling points of each cell. The phase-recording characteristic is estimated using the retrieved phase values. Next, a computer simulation is executed to reveal the influence of errors in the measurement of magnitude. The simulation result shows that the recorded phase distribution can approximately be retrieved when the rms error added to the magnitude is approximately 10 percent of its average. Furthermore, the validity of the phase distribution retrieved in the experiment is discussed.

关键词： Kinoform Gerchberg-Saxton algorithm phase retrieval phase-recording characteristic

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GAUSSIAN-BEAM PROFILE SHAPING BY ACOUSTOOPTIC BRAGG-DIFFRACTION

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APPLIED OPTICS 1994年第20期33卷 4508-4515页

作者： MCNEILL, MD POON, TC []The authors are with the Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute State University Blacksburg Virginia 24061.

We study how Gaussian laser-beam profiles can be modified into a desired form using acousto-optic Bragg diffraction. By exploiting the angular dependence of Bragg diffraction of plane waves by acoustic gratings, we demonstrate that the conversion from a Gaussian-profile beam into either a near-field or a far-field flattop profile is possible.

关键词： Acoustooptic modulators image processing Laser fusion optical data processing Pattern recognition Spatial light modulators

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Velocity tuned generalized Sobel operators for multiresolution computation of optical flow

Velocity tuned generalized Sobel operators for multiresoluti...

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The 1994 1st IEEE International Conference on image processing

作者： Gökstorp, M. Danielsson, P.-E. Image Processing Laboratory Computer Engineering Division Department of Electrical Engineering Linköping University LinköpingS-581 83 Sweden

optical flow computation may be divided into four processing steps where the first is extraction of image features suitable for flow estimation. Using a generalization of the basic flow constraint it is possible to estimate flow vectors from a set of feature images obtained from the input image sequence. Generalized Sobel operators provide a suitable set of feature extraction operators. The set of five filters up to second order provides good approximations of ideal edge and line detectors. A review of spatial and frequency constraints on optical flow suggests a multiresolution approach to optical flow where the initial feature extractors consists of velocity tuned operators. We show that two-dimensional generalized Sobel operators may be extended to spatio-temporal velocity tuned filters for optical flow estimation. Experimental results compare well to existing methods. © 1994 IEEE.

关键词： optical flows

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Pulse-width modulation using an acousto-optic modulator

Pulse-width modulation using an acousto-optic modulator

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Southeastern Symposium on System Theory

作者： M.D. McNeill Ting-Chung Poon D. Moore Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University USA

The authors show how an acousto-optic modulator operating in the first Bragg regime can be configured to produce pulse-width modulated (PWM) signals. Specifically, a hybrid optical bistable operating as a threshold device is used to produce pulses whose width is proportional to the input signal's amplitude. In addition, background information outlining the principles of acoustooptic interaction is included to provide sufficient understanding of Bragg cells. Both theoretical and experimental results are presented.< >

关键词： Pulse modulation Space vector pulse width modulation Pulse width modulation optical modulation optical refraction optical bistability optical pulses Acoustic diffraction optical diffraction Laboratories

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Real-time histogram generation using optical scanning

Real-time histogram generation using optical scanning

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Southeastern Symposium on System Theory

作者： R.J. Pieper J.K. Richstein C.-M. Ho A. Lee T.-C. Poon Department of Electrical and Computer Engineering Naval Postgraduate School Monterrey CA USA Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

A prototype of an optical-electronic histogram generator has been designed and tested for 1-D objects. In this scheme, the object to be analyzed is laser scanned. The resulting optical signal is detected by a photodetector which generates an electrical signal output which is subsequently analyzed with a combination of analog and digital electronics. The system has shown to be fairly modular in design. Various aspects of the extension of the design to two dimensions is discussed.< >

关键词： Histograms Circuits Signal generators Nonlinear optics Clocks Photodetectors Mirrors Signal analysis optical scattering Signal processing

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A CMOS VLSI IC for real-time opto-electronic two-dimensional histogram generation

A CMOS VLSI IC for real-time opto-electronic two-dimensional...

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Southeastern Symposium on System Theory

作者： J.K. Richstein D.J. Fouts R.J. Pieper T.-C. Poon Department of Electrical and Computer Engineering Naval Postgraduate School Monterrey CA USA Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

Histogram generation, a standard image processing operation, is a record of the intensity distribution in the image. A prototype of an optical-electronic histogram generator has been designed and tested for 1D objects using wirewrapped MSI TTL components (Richstein et al. 1993). The overall system design is such that the electronic signal obtained from the optically scanned two-dimensional semi-opaque image is processed and displayed within a period of one cycle of the scanning process. The authors report a VLSI design to be used in a two-dimensional real-time histogram generation scheme.< >

关键词： Very large scale integration CMOS integrated circuits Histograms optical recording image generation image processing Prototypes optical devices optical design Testing

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Computing depth from out-of-focus blur using a local frequency representation

Computing depth from out-of-focus blur using a local frequen...

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International Conference on Pattern Recognition

作者： M. Gokstorp Image Processing Laboratory Computer Engineering Division Department of Electrical Engineering Linkoping University Sweden

We present a method to compute depth from the amount of defocus in two images obtained from the same view-point but with different camera parameter settings. The change in defocus (blur) between the two images is proportional to the depth in the scene. We introduce a novel method to estimate the blur using a multiresolution local frequency representation of the input image pair. A confidence measure is used to discriminate between high error and low error blur estimates. Quantitative experimental results are shown for both real and synthetic images.

关键词： Layout Cameras Frequency estimation Robustness Lenses Focusing optical imaging Geometry image processing Laboratories

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Velocity tuned generalized Sobel operators for multiresolution computation of optical flow

Velocity tuned generalized Sobel operators for multiresoluti...

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IEEE International Conference on image processing

作者： M. Gokstorp P.-E. Danielsson Image Processing Laboratory Computer Engineering Division Department of Electrical Engineering Linköping University Sweden

关键词： optical computing image motion analysis optical filters Band pass filters Gabor filters Feature extraction Spatial resolution Frequency Equations image edge detection

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