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Human Vision, Visual processing, and Digital Display 1989

作者： Mitra, Sanjit K. Zarrinnaal, Iraj Wang, Yao Signal and Image Processing Laboratory Department of Electrical and Computer Engineering University of California Santa BarbaraCA93106 United States

Digital processing of black and white images has received most attention during the last 25 years, and has led to various algorithms for the enhancement, smoothing, and zooming of images. Due to the decreasing cost and increasing availability of color image acquisition and display equipment along with the computing systems of higher performance, it is expected that the digital processing of color images will rapidly grow in demand. In this paper we review our experiences with the processing of color images. In particular, algorithms for the contrast enhancement, smoothing and zooming of color images are investigated. The effects of applying these methods in color coordinates other than RGB are examined and considerations with respect to performance, time efficiency and compatibility with some popular algorithms developed for monochrome images are discussed. © 1989 SPIE. All rights reserved.

关键词： Color

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Image segmentation using human visual system properties with applications in image compression

Image segmentation using human visual system properties with...

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Human Vision, Visual processing, and Digital Display 1989

作者： Peterson, Heidi A. Rajala, Sarah A. Delp, Edward J. Computer Vision and Image Processing Laboratory School of Electrical Engineering Purdue University West LafayetteIN47907 United States Department of Electrical and Computer Engineering North Carolina State University RaleighNC27695 United States

Many image compression techniques involve segmentation of a gray level image. With such techniques, information is extracted that describes the regions in the segmented image, and this information is then used to form a coded version of the image. In this paper we present a region-growing-based segmentation technique that incorporates human visual system properties, and describe the use of this technique in image compression. We also discuss the effect of requantizing a segmented image. Requantization of a segmented image is useful because it can lead to a reduction in the number of bits required to code the description of the regions in the segmented image. This results in a lower data rate. We show that the number of gray levels in a segmented image can be reduced by a factor of at least twelve, without noticeable degradation in the quality of the segmented image. This result is attributable to human visual system properties having to do with contrast sensitivity, and to the fact that requantization of a segmented image does not usually reduce significantly the number of distinct segments in the image. In addition, in this paper we explore the relationship between the number of segments in an image, and the extent of requantization possible before noticeable degradation occurs in the image. Finally, we discuss the impact of the above results on image compression algorithms, and present some experimental results. © 1989 SPIE. All rights reserved.

关键词： Image compression

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Synthesis of Feedback Control for Forbidden State Problems in Discrete Manufacturing Systems

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IFAC Proceedings Volumes 1989年第14期22卷 11-16页

作者： L.E. Holloway B.H. Krogh Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA 15213 USA

This paper concerns the supervisory coordination and control of concurrent activities in an automated manufacturing facility. In contrast to commonly used simulation models which integrate the control policy with the system model, the subsystem state transition logic is represented by a class of controlled Petri nets (CPNs) with external inputs to be determined by the control synthesis algorithm. We formulate the forbidden state control problem in the CPN context and present a computationally efficient algorithm for generating maximally permissive controls which guarantee the system will avoid the forbidden states while permitting a maximal amount of flexibility in the system operation. The problem formulation and control synthesis algorithm is illustrated for an example of AGV coordination, and several classes of manufacturing control problems which can be addressed within this framework are identified.

关键词： computer control control system synthesis discrete systems manufacturing processes supervisory control synthesis methods

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A nonlinear spectrum compression algorithm for the hearing impaired

A nonlinear spectrum compression algorithm for the hearing i...

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Annual Northeast Bioengineering Conference

作者： L.D. Paarmann M.D. Guiher Signal Processing Laboratory Department of Electrical and Computer Engineering Drexel University Philadelphia PA USA

A technique is proposed for increasing the speech intelligibility of persons with profound sensorineural hearing loss. The processing is based on a modification of the chirp-z transform that allows for nonlinear sampling along an arbitrary contour of the z-plane. Although the theory allows the nonlinear sampling to be arbitrary, an example showing that it is appropriate for nonlinear spectrum compression to aid the hearing-impaired is given. Samples are linearly spaced along the unit circle for a specified low-frequency segment; beyond the break-point the samples are nonlinearly spaced, perhaps spiraling inward to enhance spectral peaks, with the spacing width increasing with increasing frequency following an exponential function. A standard inverse DFT of these frequency samples returns the spectrum-compressed sequence. processing of continuous speech requires windowing and processing of data in a manner similar to the short-time Fourier transform (STFT). The authors present the theoretical basis for, and development of, the algorithm.< >

关键词： Compression algorithms Auditory system Sampling methods Speech processing Frequency Signal processing algorithms Deafness Chirp Laboratories Signal sampling

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Partial shape recognition: a landmark-based approach

Partial shape recognition: a landmark-based approach

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IEEE International Conference on Systems, Man and Cybernetics

作者： N. Ansari E.J. Delp Center for Communications and Signal Processing Electrical and Computer Engineering Department New Jersey Institute of Technology Newark NJ USA Computer Vision and Image Processing Laboratory School of Electrical Engineering Purdue University IN USA

A technique to guide landmark matching known as hopping dynamic programming is described. The location of the model in the scene is estimated with a least-squares fit. A heuristic measure is then computed to decide if the model is in the scene. The shape features of an object are the landmarks associated with the object. The landmarks of an object are defined as the points of interest of the object that have important shape attributes. Examples of landmarks are corners, holes, protrusions, and high-curvature points.< >

关键词： Shape measurement Layout computer vision Pattern recognition Signal processing Image processing Laboratories Performance evaluation Least squares approximation Feature extraction

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Adaptive line enhancement using multirate techniques

Adaptive line enhancement using multirate techniques

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International Conference on Acoustics, Speech, and Signal processing (ICASSP)

作者： V.S. Somayazulu S.K. Mitra J.J. Shynk Signal & Image Processing Laboratory Department of Electrical & Computer Engineering University of California Santa Barbara CA USA

A novel structure for multirate adaptive filtering with lower computational complexity and improved performance of the adaptive algorithm is introduced. It uses auxiliary subbands and a modified filter bank with decimated subbands. It avoids the aliasing distortions encountered in critically decimated overlapping filter banks as well as the spectral gaps in nonoverlapping filter banks. The authors show that this structure has a lower computational complexity than previously reported structures. computer simulations are included showing the improvement in performance that can be achieved with the new structure operating as an adaptive line enhancer (ALE) compared with the conventional ALE.< >

关键词： Adaptive filters Finite impulse response filter Filter bank Computational complexity Convergence Line enhancers Narrowband Adaptive algorithm Echo cancellers Teleconferencing

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On fairness and conflicts in Petri nets

On fairness and conflicts in Petri nets

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Midwest Symposium on Circuits and Systems (MWSCAS)

作者： R.S. Sreenivas B.H. Krogh Laboratory for Automated Systems and Information Processing Department of Electrical Engineering and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

The notions of fairness and conflicts in live, bounded, and strongly connected Petri nets (PNs) are formally related. The PN model of a resource-sharing concurrent system (RSCS) is conflict free when the firing of an enabled transition does not disable another transition in the net. Conflicts in the PN represent unresolved resource allocation conditions. The PN is fair when the firing of any transition more than a given number of times is a sufficient condition for all the transitions in the net to have fired. When the PN is fair, no process in the system can be starved; that is resources are allocated so that all tokens progress through the net. Although these concepts are not equivalent, it is shown that they are strongly related to each other when the PN model is live, bounded, and strongly connected. A computational method for finding conflicts is presented, and the concepts are illustrated with an example of buffer allocation in a sorting algorithm.< >

关键词： Petri nets Resource management Sufficient conditions Laboratories Information processing Concurrent computing Sorting Large-scale systems Algorithm design and analysis Logic

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An approach for coordinating mobility and manipulation

An approach for coordinating mobility and manipulation

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IEEE International Conference on Systems engineering

作者： Carriker Khosla Krogh Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

The authors discuss the problem of planning a task for a robotic system that consists of a manipulator mounted on a mobile base. The task planning problem is formulated as a nonlinear optimization problem. The cost of point-to-point motion in three-dimensional Cartesian space is decomposed into two components representing the qualitative difference between motion due to the mobile base and motion due to the manipulator system. Task specifications at each end of the motion impose constraints on the endpoint configurations. The resulting regions of feasible positions and configurations are unconnected and nonconvex. Thus, standard algorithms for nonlinear optimization lead to nonextremal solutions. A heuristic method is presented for searching a tree of starting points for a standard numerical algorithm to find a global minimum for the cost function. The problem formulation is illustrated for a three-degrees-of-freedom (DOF) manipulator on a simple two-DOF mobile base, and tradeoffs between base motion and manipulator motion are evaluated with respect to cost function weighting coefficients.< >

关键词： Mobile robots Numerical analysis Optimization methods Robots Mechanical variables control

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Efficient Synthesis of Control Logic for a Class of Discrete Event Systems

Efficient Synthesis of Control Logic for a Class of Discrete...

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American Control Conference (ACC)

作者： Lawrence E. Holloway Bruce H. Krogh Laboratory for Automated Systems and Information Processing Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA USA

Real-world applications of the emerging theory of controlled discrete event systems (DESs) will not be realized until the obstacle of computational complexity is overcome. This paper presents a step in that direction by developing a computationally efficient solution for a class of forbidden state problems. We consider DESs which can be modeled as cyclic controlled marked graphs (CMGs), a class of controlled Petri nets (CPNs). The distributed representation of the DES state in terms of the CMG marking permits an efficient specification of the forbidden states in terms of individual place markings. More importantly, we show that the graphical representation of the state transition logic in a CMG can be used to synthesize state feedback logic which is maximally permissive while guaranteeing the forbidden states will not occur. The practical application of the theoretical results is illustrated for an example of automated guided vehicle (AGV) coordination in a flexible manufacturing facility.

关键词： Control system synthesis Logic Discrete event systems Automatic control Petri nets State feedback Laboratories Information processing Application software Computational complexity

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Parameter extraction of microwave transistors using tree annealing

Parameter extraction of microwave transistors using tree ann...

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IEEE/Cornell Conference on Advanced Concepts in High Speed Semiconductor Devices and Circuits

作者： M.B. Steer G.L. Bilbro R.J. Trew S.G. Skaggs High Frequency Electronics Laboratory and the Center for Communications and Signal Processing Department of Electrical and Computer Engineering North Carolina State University Raleigh NC USA

The authors have developed an alternative formulation of simulated annealing using a tree-based Metropolis procedure called tree annealing. Tree annealing is suited to continuous optimization problems and, in particular, to transistor parameter extraction. The tree annealing optimization algorithm was used to extract the parameters of the HBT (heterojunction bipolar transistor) of U.K. Mishra et al. (IEDM Tech. Dig., p.180-3, Dec. 1988) using a physically based equivalent circuit and deembedded scattering parameter measurements from 45 MHz to 26.5 GHz. Good results were obtained from the parameter extraction technique, and the ability of MFA not to be locked in local minima enabled a physically based equivalent circuit model to be used. Tree annealing is essentially a smart random search technique and so requires many more functional evaluations than do gradient-based minimization algorithms. However, no startling guess is required, and the bounds on parameter values can be widely separated with little effect on optimization time.< >

关键词： Parameter extraction Microwave transistors Simulated annealing Equivalent circuits Combinatorial mathematics Robustness Frequency Laboratories Microwave communication Signal processing

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