Showing papers by "David P. Casasent published in 1983"
TL;DR: Optical matrix processors using acoustooptic transducers are described with emphasis on new systolic array architectures using frequency multiplexing in addition to space and timeMultiplexing, with new technique for handling bipolar data on such architectures.
Abstract: Optical matrix processors using acoustooptic transducers are described with emphasis on new systolic array architectures using frequency multiplexing in addition to space and time multiplexing. A Kalman filtering application is considered as our case study from which the operations required on such a system can be defined. This also serves as a new and powerful application for iterative optical processors. The importance of pipelining the data flow and the ordering of the operations performed in a specific application of such a system are also noted. Several examples of how to effectively achieve this are included. A new technique for handling bipolar data on such architectures is also described.
54 citations
TL;DR: An optical processor that realizes a generalized chord transformation is described and the wedge-ring detector samples of an autocorrelation are shown to be the histograms of the chord distributions.
Abstract: An optical processor that realizes a generalized chord transformation is described. The wedge-ring detector samples of an autocorrelation are shown to be the histograms of the chord distributions. This dimensionality reduced set of features is used as the feature vector inputs for a Fisher linear classifier to determine the class of the input object independent of geometrical distortions. Initial discussions on the use of different classifiers, the polarity of the classifier’s output, and selection of the image training set are also advanced.
27 citations
TL;DR: It is shown that matrix–vector operations and iterative algorithms can be performed totally in residue notation and an architecture using a frequency-multiplexed optical systolic array feedback processor is suggested.
Abstract: The use of residue arithmetic to increase the accuracy and reduce the dynamic range requirements of optical matrix-vector processors is evaluated. It is determined that matrix-vector operations and iterative algorithms can be performed totally in residue notation. A new parallel residue quantizer circuit is developed which significantly improves the performance of the systolic array feedback processor. Results are presented of a computer simulation of this system used to solve a set of three simultaneous equations.
22 citations
TL;DR: Two coherent optical systems are described that can realize local nonlinear preprocessing operators such as the Sobel edge-enhancement function in parallel on a 2-D input image using novel coherent systems using complex arithmetic with magnitude evaluation of the output pattern.
Abstract: Two coherent optical systems are described that can realize local nonlinear preprocessing operators such as the Sobel edge-enhancement function in parallel on a 2-D input image. By local, we refer to the size of the image region rather than a nonstationary process. Realization of such operators using a multiple-exposure matched spatial filter and a computer-generated hologram is discussed. Experimental results using these techniques for 3 × 3 and 5 × 5 Sobel operators, respectively, are presented. Our techniques can be extended to larger window sizes and other edge-enhancement operators. These new operators are achieved by novel coherent systems using complex arithmetic with magnitude evaluation of the output pattern.
21 citations
TL;DR: New direct and implicit algorithms for optical matrix-vector and systolic array processors are considered and the Householder QR matrix-decomposition algorithm is considered as a specific example of a direct solution.
Abstract: New direct and implicit algorithms for optical matrix-vector and systolic array processors are considered. Direct rather than indirect algorithms to solve linear systems and implicit rather than explicit solutions to solve second-order partial differential equations are discussed. In many cases, such approaches more properly utilize the advantageous features of optical systolic array processors. The matrix-decomposition operation (rather than solution of the simplified matrix-vector equation that results) is recognized as the computationally burdensome aspect of such problems that should be computed on an optical system. The Householder QR matrix-decomposition algorithm is considered as a specific example of a direct solution. Extensions to eigenvalue computation and formation of matrices of special structure are also noted.
9 citations
TL;DR: A frequency-multiplexed optical systolic array processor for matrix-decomposition is described and the data flow and ordering of operations for LU decomposition or gaussian elimination and LL T or Cholesky decomposition on this system are detailed using an algorithm that utilizes the parallel processing ability of the optical sydynamic array processor.
6 citations
13 Dec 1983
TL;DR: A correlation architecture using a matched spatial filter of a synthetic discriminant function is employed to achieve the required performance and initial performance obtained in the face of noise is discussed.
Abstract: The problem of recognizing multiple objects in a highly cluttered background in the face of geometrical object distortions is addressed in this paper. A correlation architecture using a matched spatial filter of a synthetic discriminant function is employed to achieve the required performance. Synthesis of the synthetic discriminant function is discussed as is the initial performance obtained in the face of noise. Initial remarks are advanced on various methods to select the training set of images to use in this algorithm.
5 citations
23 May 1983
TL;DR: The synthetic discriminant function concept together with its modifications of maximum common information filters and decorrelation transformations are reviewed and a unified procedure for determining the coefficients for linear combination filters for recognition of objects in different orientations and from different aspect views is advanced.
Abstract: The synthetic discriminant function concept together with its modifications of maximum common information filters and decorrelation transformations are reviewed. We then advance a unified procedure for determining the coefficients for such linear combination filters for recognition of objects in different orientations and from different aspect views. Our formulation utilizes only deterministic techniques and a correlation matrix observation space. This formulation is most attractive for the realization of shift-invariant filters for use in correlator architectures. We then advance the highlights of our initial results on the performance of this new type of generalized shift-invariant filter.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
5 citations
23 May 1983
TL;DR: This paper advances a new optical finite-order cosine-processor that can compute the moments and discusses how the outputs from this system can easily be corrected for various optical system errors and the design of a reduced size breadboard optical system.
Abstract: A moment-based pattern recognition system is most appropriate for providing information on the presence, classification and orientation of an object in the field-of-view of a sensor Such features are ideal for robotic pattern recognition and parts handling This paper reviews our hybrid optical/digital system to achieve the above objectives and includes initial demonstration results We then advance a new optical finite-order cosine-processor that can compute the moments and we discuss how the outputs from this system can easily be corrected for various optical system errors and the design of a reduced size breadboard optical system
5 citations
01 Jan 1983
TL;DR: Many of the linear algebra operations and algorithms possible on optical matrix-vector processors are reviewed in this article, with emphasis given to the use of direct solutions and their realization on systolic optical processors.
Abstract: Many of the linear algebra operations and algorithms possible on optical matrix-vector processors are reviewed. Emphasis is given to the use of direct solutions and their realization on systolic optical processors. As an example, implicit and explicit solutions to partial differential equations are considered. The matrix-decomposition required is found to be the major operation recommended for optical realization (since digital systems can easily solve the simplified matrix-vector problem that results). The pipelining and flow of data and operations are noted to be key issues in the realization of any algorithm on an optical systolic array processor. A realization of the direct solution by Householder OR decomposition is provided as a specific case study.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
4 citations
TL;DR: This paper describes two new hybrid time and space integrating acoustooptic correlators and their use in spread spectrum applications and a statistical analysis of coherent and partially coherent output time integration is included.
Abstract: In this paper we describe two new hybrid time and space integrating acoustooptic correlators and their use in spread spectrum applications. These systems employ 1-D or 2-D masks and are of use for many spread spectrum coding schemes and very long codes. Synchronization and demodulation of very long codes are achieved in these systems with an infinite range delay search and with nearly the full processing gain of the code. A statistical analysis of coherent and partially coherent output time integration is included (this appears to be most appropriate for any hybrid processor) together with initial simulation results.
28 Nov 1983
TL;DR: The first error source model for an optical systolic array processor is advanced and a direct solution to linear algebraic equations is found to be less sensitive to various optical system error sources than is an indirect solution.
Abstract: Direct and indirect solutions to linear algebraic equations (LAEs) are considered with attention to the use of optical acousto-optic (AO) systolic array processors. Specific attention is given to error sources in one AO systolic processor. A case study of an LAE solution is conducted. The first error source model for an optical systolic array processor is advanced. Using this and digital computer modeling, a direct solution is found to be less sensitive to various optical system error sources than is an indirect solution. Acoustic attenuation is found to be the dominant error source in the AO systolic array processor considered. Related error source remarks on different bipolar data representation schemes and on optical versus digital solutions to a triangular system of equations are also advanced.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
TL;DR: It is noted that the simplified system of equations presented by Casasent and Ghosh (1983) can also be solved optically, and one realization of this is described, with attention given to data flow and speed for the case of a lower triangular system of equation.
Abstract: It is noted that the simplified system of equations presented by Casasent and Ghosh (1983) can also be solved optically. One realization of this is described, with attention given to data flow and speed for the case of a lower triangular system of equations. The solution of an upper triangular system of equations can be handled in analogous fashion. The problem requires a matrix-vector processor. Only one carrier frequency input to the acoustooptic cell and only one output detector are used. To multiply a matrix by a vector in this system, the time-multiplexed vector elements are fed into the acoustooptic cell.
15 Apr 1983
TL;DR: Initial remarks, results, examples and solutions for each of the design, error analysis, component accuracy required, computational capacity, data flow and pipelining, plus the algorithm and application all seriously impact the use of optical systolic array processors.
Abstract: The design, error analysis, component accuracy required, computational capacity, data flow and pipelining, plus the algorithm and application all seriously impact the use of optical systolic array processors. This paper provides initial remarks, results, examples and solutions for each of these issues.© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
01 Jan 1983
TL;DR: A new application (Kalman filtering) for such architectures is investigated: all required operations are detailed, their realization by optical and special-purpose analog electronics are specified; and the processing time of the system is quantified.
Abstract: Optical systolic array processors represent a powerful and general-purpose set of optical architectures with high computational rates. A new application (Kalman filtering) for such architectures is investigated: all required operations are detailed, their realization by optical and special-purpose analog electronics are specified; and the processing time of the system is quantified. The specific Kalman filter application chosen is an air-to-air missile guidance controller. The goal was to realize a fully-adaptive Kalman filter to allow a new measurement every 1msec. This work also addresses the vital issue of flow and pipelining of data and operations in a systolic array processor. Our work is sufficiently general to be applicable to an optical or digital systolic array processor realization.Optical systolic array processors represent a powerful and general-purpose set of optical architectures with high computational rates. A new application (Kalman filtering) for such architectures is investigated: all required operations are detailed, their realization by optical and special-purpose analog electronics are specified; and the processing time of the system is quantified. The specific Kalman filter application chosen is an air-to-air missile guidance controller. The goal was to realize a fully-adaptive Kalman filter to allow a new measurement every 1msec. This work also addresses the vital issue of flow and pipelining of data and operations in a systolic array processor. Our work is sufficiently general to be applicable to an optical or digital systolic array processor realization.
15 Apr 1983
TL;DR: The authors' unified synthetic discriminant function (SDF) filter synthesis technique using the correlation matrix of the image training set is reviewed and Excellent performance (over 90% correct classification) was achieved.
Abstract: Our unified synthetic discriminant function (SDF) filter synthesis technique using the correlation matrix of the image training set is reviewed Four different synthetic discriminant functions for intra-class recognition, inter-class discrimination and both intra and inter-class pattern recognition are considered All techniques proposed are appropriate for object identification, location and classification in the presence of 3-D geometrical distortions in the input object Initial results obtained on a set of four different classes of infrared ship imagery are presented Excellent performance (over 90% correct classification) was achieved© (1983) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only
11 Aug 1983
TL;DR: The basic acousto-optic signal processing architectures (spectrum analyzer, space-inte-grating, time-integrating and triple product processor) systems and algorithms such as the chirp-Z transform are reviewed and four new matrix-vector iterative feedback systems are described.
Abstract: The basic acousto-optic signal processing architectures (spectrum analyzer, space-integrating, time-integrating, and triple product processor) systems and algorithms such as the chirp-Z transform are reviewed. New acousto-optic data processing systems and applications that utilze these basic architectures and new ones are described. These include a matched spatial filter acousto-optic processor, two new hybrid time and space-integrating systems, a triple product processor, and four new matrix-vector iterative feedback systems.
28 Nov 1983
TL;DR: This paper focuses on feature extraction pattern recognition techniques (specifically a chord distribution and a moment feature space) and notes the various linear algebra operations required in distortion-invariant pattern recognition.
Abstract: Many linear algebra operations, matrix inversions, etc. are required in pattern recogni tion as well as in signal processing. In this paper, we concentrate on feature extraction pattern recognition techniques (specifically a chord distribution and a moment feature space). For these two case studies, we note the various linear algebra operations required in distortion- invariant pattern recognition. Systolic processors can easily perform all required linear algebra functions. 1. INTRODUCTION Linear algebra operations are required in many signal processing applications and these have been extensively discussed elsewhere in this volume. In this paper, I note that similar operations are also required in many pattern recognition and object identification applica tions. In this paper, specific attention is given to feature extraction or feature space based pattern recognition problems and to viable applications such as achieving object rec ognition in the face of geometrical distortions in the input image. The two feature extrac tion case studies considered are the use of a chord distribution and a moment feature space. Each of these results in considerably different linear algebra operations required on the object features to achieve the desired object identification. Sections 2 and 3 address the chord distribution feature space and Section 4 addresses the moment feature space case study.