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image and Video processing 1993

作者： Yu, Tian-Hu Mitra, S.K. Department of Electrical and Computer Engineering Signal and Image Processing Laboratory University of California Santa BarbaraCA93106 United States

In direct methods of contrast enhancement, a contrast measure is first defined, which is then modified by a mapping function to generate the pixel value of the enhanced image. Various mapping functions such as the square root function, the exponential function, etc., have been introduced for the contrast measure modification. However, these functions do not produce satisfactory contrast enhancement results and are usually sensitive to noise and digitization effects. In addition, they are computationally complex from the point of view of implementation. In this paper, we propose a simple polynomial mapping function for the contrast measure modification. The polynomial function is easy to implement on digital computers and provides very satisfactary contrast enhancement. We also introduce an adaptive clipping technique to control the dynamic range of the output image. © 1993 SPIE. All rights reserved.

关键词： Exponential functions

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Real-time pattern recognition by joint-Fourier transform correlation

Real-time pattern recognition by joint-Fourier transform cor...

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International Conference on Manufacturing Automation 1992

作者： Poon, Ting-Chung Pieper, Ronald J. Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute State University BlacksburgVA24061 United States Department of Electrical and Computer Engineering Naval Postgraduate School MontereyCA93943 United States

Two commonly used optical correlation techniques, matched spatial filtering and joint-Fourier transform correlation, are briefly reviewed. A recently proposed real-time joint-Fourier transform correlation is then disc... 详细信息

关键词： Fourier transforms

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REAL-TIME NONLINEAR image-processing USING AN ACTIVE optical-SCANNING TECHNIQUE

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OPTICS AND LASER TECHNOLOGY 1991年第1期23卷 19-24页

作者： DUNCAN, BD POON, TC PIEPER, RJ The authors are in the Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University 675 Whittemore Hall Blacksburg Virginia 24060 USA

Real-time non-linear image processing has been achieved using an active optical scanning technique. This paper reports experimental results in edge extraction for both binary and grey-scale transmissive objects. Binary edge extraction is achieved using morphological transformations, while grey-scale edge extraction is achieved using a threshold decomposition technique. Advantages and limitations of both techniques are identified.

关键词： EDGE EXTRACTION MORPHOLOGICAL TRANSFORMATION optical SCANNING NONLINEAR image processing

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A NEW APPROACH TO image-CODING USING 1-D SUBBAND FILTERING 2

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CONF ON image processing ALGORITHMS AND TECHNIQUES

作者： YU, TH MITRA, SK Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Santa Barbara 93106 CA United States

ISBN: (纸本)0819405515

Conventional subband coding for image data compression uses two-dimensional (2-D) separable QMF banks in which the analysis and synthesis filters are composed of 1-D filters. Such an implementation produces a large size output image as a result of the convolution process. Various signal extension methods have been proposed to solve this problem. However, these methods have one or more of the following drawbacks: Generation of boundary noise, inability to guarantee aliasing cancellation, and increased computational complexity. In this paper, we present an alternative solution to the problem by converting a 2-D image array to a 1-D array and then using an 1-D QMF bank to process the 1-D signal. In our approach, most of the above drawbacks mentioned above are eliminated. In addition, our approach offers more flexibilities in the type of the filter that can be implementated. © 1991 SPIE. All rights reserved.

关键词： image coding

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A NOVEL NONLINEAR FILTER FOR image-ENHANCEMENT 2

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CONF ON image processing ALGORITHMS AND TECHNIQUES

作者： YU, TH MITRA, SK KAISER, JF Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Santa Barbara 93106 CA United States Bell Communications Research Inc. Room 2A-281 445 South Street Morristown 07962-1910 NJ United States

ISBN: (纸本)0819405515

Recently, a very simple nonlinear algorithm, the so-called Teager's algorithm, has been introduced to calculate the energy of a one-dimensional sequence [1]. In this paper, this algorithm is extended to two-dimensional signals and applied to the contrast enhancement of images. Initial simulation results indicate that the proposed approach yields a superior and visually pleasing enhancement of natural images. The new algorithm is very simple and permits fast implementation. © 1991 SPIE. All rights reserved.

关键词： image enhancement

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Automatic neural arbor reconstruction

Automatic neural arbor reconstruction

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IEEE Symposium on Nuclear Science (NSS/MIC)

作者： P.M. Gregson Computer Vision and Image Processing Laboratory Department of Electrical Engineering Technical University of Nova Scotia Halifax NS Canada

An algorithm for detecting neural processes in serial optical sections for use in an automated three-dimensional neural reconstruction system is presented. This parsimonious, nonlinear, psychophysically motivated algorithm addresses the problems specific to neural element detection and localization, viz., images with minimal resolution, operators with small spatial supports, highly curved, filamentous features, large variation in feature intensity profile, poor signal-to-noise ratio, and determination of depth without stereo. One first finds the magnitude and orientation of the maximum intensity second directional derivative. A family of curves is locally fitted to these data, and the projections of the data on the curve family are found. If a pixel lies on a curve with sufficient total projection, it is labeled with the magnitude, orientation, curvature, spatial extent, and element displacement. Depth is interpolated from the spatial extent data for corresponding neighborhoods in three adjacent (in depth) images by using an approximation to the depth-dependent optical point spread function. Experimental results using photomicrographs of cat visual cortex are presented.< >

关键词： image reconstruction computer vision Displays Spatial resolution Neural networks Nonlinear optics optical interconnections Neurons image processing Laboratories

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SYSTEM CHARACTERIZATION OF APODIZED ACOUSTOOPTIC BRAGG CELLS

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JOURNAL OF THE optical SOCIETY OF AMERICA A-OPTICS image SCIENCE AND VISION 1990年第9期7卷 1751-1758页

作者： PIEPER, RJ POON, TC Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg Virginia 24061 USA

An acousto-optic cell can be characterized in terms of the spatial impulse response or a transfer function that relates the angular plane-wave spectrum of the output light field to that of the input light field. A general methodology for calculating the acousto-optic impulse response and transfer function is developed. This methodology is then specifically applied to the case of acousto-optic cells with and without Hamming apodization of the sound field. Results are obtained and compared with analytical expressions for the conventional Bragg cell for a typical value of the Klein–Cook Q parameter and sound intensity. Finally, implications of the results relating to beam shaping in the scattered light field are discussed.

关键词： Acoustooptic modulators Beam shaping Diffraction efficiency Laser beam shaping Light beams Light fields

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optical TRANSFER-FUNCTIONS FOR DEFOCUSED 2-PUPIL SYSTEMS INVOLVING ANNULAR GEOMETRIES

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JOURNAL OF MODERN OPTICS 1990年第12期37卷 2055-2072页

作者： PIEPER, RJ POON, TC Optical Image Processing Laboratory The Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA 24061 United States

An exact solution for the cross-correlation between two different circular apertures under defocused conditions in a two-pupil system is derived. The result is directly applicable to finding the optical transfer function (OTF) for standard examples including annular apertures. Some novel examples leading to OTFs showing bandpass and band-reject properties are also investigated.

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Feature extraction using an optical scanning system

Feature extraction using an optical scanning system

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Southeastern Symposium on System Theory

作者： B.D. Duncan R.J. Pieper T. Poon Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

Real-time image processing has been achieved by using an optical scanning system in conjunction with electronic hardware. A report of experimental results on edge extraction and image thresholding for transmissive objects is presented. Advantages and limitations of the techniques are identified. The results indicate that real-time edge extraction and image thresholding can be satisfactorily achieved.< >

关键词： Feature extraction Photodetectors optical filters image processing Lenses Low pass filters Oscilloscopes Machine vision Real time systems Focusing

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image reconstruction capabilities of binary phase-only filters

Image reconstruction capabilities of binary phase-only filte...

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Southeastern Symposium on System Theory

作者： K. Raj R.J. Pieper T.-C. Poon Optical Image Processing Laboratory Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

A qualitative study is made of the image reconstruction capabilities of binary phase-only filters (BPOFs) and the binary Hartley phase-only filters (BHPOFs). It is found that the BPOF and BHPOF reconstruct edge-enhanced versions of the original object functions and that the image reconstruction of the BHPOF is better than that of the BPOF. However, for some applications such as optical interconnections, edge enhanced reconstruction is not desirable. Filled image reconstruction is achieved by using a Gaussian apodized mask on the BPOF and BHPOF. Also, a real-time hybrid optical system for such filled image reconstruction is presented.< >

关键词： image reconstruction optical filters optical modulation optical interconnections optical noise Pattern recognition Fourier transforms Frequency image processing Laboratories

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