This brief describes an algorithmic development of the optimal low-rank approximation (LRA) of multidimensional (M-D) signals with M greater than or equal to 3. The algorithms developed can he regarded as a dimensiona...
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This brief describes an algorithmic development of the optimal low-rank approximation (LRA) of multidimensional (M-D) signals with M greater than or equal to 3. The algorithms developed can he regarded as a dimensional generalization of the singular value decomposition (SvD) which is of fundamental importance for analyzing signals that can be represented in a matrix form. In particular, iterative algorithms for optimal and suboptimal LRA of three-dimensional (3-D) arrays are presented in detail. Application of the 3-D LRA to the compression of image sequences is discussed.
Ultrasound is one of the leading medical imaging modalities because it is safe, noninvasive, portable, easy to use, relatively inexpensive and displays images in real-time. Due to its real-time nature, an ultrasound m...
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Ultrasound is one of the leading medical imaging modalities because it is safe, noninvasive, portable, easy to use, relatively inexpensive and displays images in real-time. Due to its real-time nature, an ultrasound machine must be able to process its incoming data quickly. High computational and throughput requirements in modern ultrasound machines have restricted their internal design to algorithm-specific hardware with limited programmability. Adding new ultrasound imaging applications or improving a machine's internal algorithms can require costly hardware redesigns and replacements of boards or of the entire machine. In an effort to address these problems, we have reviewed each of the essential functions in modern ultrasound machines and analyzed their computational requirements in programmable systems. These functions include dynamic downconversion, tissue signal processing, color flow processing, scan conversion, and tissue/flow decision. Our estimate of the total computing requirement to current ultrasound machines is 54.71 billion operations per second (BOPS) when transcendental functions are implemented in software and 31.26 BOPS when transcendental functions are implemented in lookup tables taking 160.26 Mbytes of memory. To investigate the feasibility of programmable generalized ultrasound systems, we have designed a flexible and parallel programmable ultrasound processing subsystem, called the Programmable Ultrasound image Processor (PUIP). As the need for programmable ultrasound machines increases in the future due to various advantages (e.g., lower system cost, faster clinical use and lower research/development expenses), it will be crucial to develop not only a high-performance, scalable, reconfigurable parallel computer architecture meeting the computing requirement, but also efficient ultrasound algorithms that can be optimally mapped into the parallel architecture. (C) 1998 Published by Elsevier Science B.v. All rights reserved.
In this paper, a general philosophy about feature windows based applications and a windows-based application are presented for analysis, algorithm development, testing and validation studies for Signal, image and Data...
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ISBN:
(纸本)0819428949
In this paper, a general philosophy about feature windows based applications and a windows-based application are presented for analysis, algorithm development, testing and validation studies for Signal, image and Data processing (SIDP) for Space-Based Surveillance (SBS) Applications. This dedicated facility is called AUG_SIDP. It performs several specialized tasks such as blur estimation, restoration, CFAR detection, clutter modeling, registration, pixel and data level fusion, target tracking and classification. It is still in the development and testing phase.
Parallel implementations of algorithms for medical imageprocessing mostly focus on the use of multiprocessor parallelism. Modern processor architectures however, provide several additional forms of parallelism at the...
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Parallel implementations of algorithms for medical imageprocessing mostly focus on the use of multiprocessor parallelism. Modern processor architectures however, provide several additional forms of parallelism at the processor level: subword parallelism, speculative execution, superscalar pipelining, very long instruction word, etc. In this article, we show that well-known parallelization techniques for multiprocessor systems can be used to exploit subword parallelism. Loop unrolling, loop fusion and if-hoisting prove to be valuable to achieve this goal. To illustrate this, we transformed the inner loops of a positron emission tomography image reconstruction algorithm. We achieved a speed-up of 45% on Sun's UltraSPARC processor. (C) 1998 Elsevier Science B.v. All rights reserved.
We present a novel content-adaptive multiresolution SAR image formation processing algorithm that incorporates dynamic, on-line detection algorithms into the image formation process. The idea is to vary image resoluti...
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ISBN:
(纸本)0819428191
We present a novel content-adaptive multiresolution SAR image formation processing algorithm that incorporates dynamic, on-line detection algorithms into the image formation process. The idea is to vary image resolution locally depending on scene content, focusing the SAR imagery to fine resolution only in regions where the scene reflectivity varies rapidly, while forming the rest of the image at coarser resolution or with reduced fidelity. Our "decision-directed" SAR image formation algorithm may have applications in systems where on-board processing or datalink constraints limits the area coverage rates or resolution. We present examples of this multiresolution SAR processing on SAR imagery and show that compression rates on the order of 70:1 or more (i.e., 0.45 bits/pixel starting from 32bits/complex sample, 16 bits/I, 16 bits/Q), can be obtained while still preserving coherent target signatures and with minor degradation in perceptual image quality.
New Class 3 imageprocessingalgorithms are presented. They are direct extensions of previously published one-dimensional algorithms. Class 3 algorithms require almost no apriori information knowledge about the signal...
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New Class 3 imageprocessingalgorithms are presented. They are direct extensions of previously published one-dimensional algorithms. Class 3 algorithms require almost no apriori information knowledge about the signal and noise that are being processed. Their performance depends upon the kind of smoothing used and on the images being processed by the filter. The previously published Class 3 filter algorithms require that the filter input be stationary, and that the noise spectrum have zero mean and be uncorrelated to the signa. For the new Class 3 imageprocessingalgorithms, the only additional assumption for the noise is that its spectrum be white. Simulations using Lena demonstrate such better performance using the new Class 3 algorithms over the standard Class S algorithms.
An investigation is made concerning implementations of competitive learning algorithms in analog vLSI circuits and systems. Analog and low power digital circuits for competitive learning are currently important for th...
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An investigation is made concerning implementations of competitive learning algorithms in analog vLSI circuits and systems. Analog and low power digital circuits for competitive learning are currently important for their applications in computationally-efficient speech and image compression by vector quantization, as required for example in portable multi-media terminals. A summary of competitive learning models is presented to indicate the type of vLSI computations required, and the effects of weight quantization are discussed. Analog circuit representations of computational primitives for learning and evaluation of distortion metrics are discussed. The present state of vLSI implementations of hard and soft competitive learning algorithms are described, as well as those for topological feature maps. Tolerance of learning algorithms to observed analog circuit properties is reported. New results are also presented from simulations of frequency-sensitive and soft competitive learning concerning sensitivity of these algorithms to precision in vLSI learning computations. Applications of these learning algorithms to unsupervised feature extraction and to vector quantization of speech and images are also described.
The task of autonomous navigation comprises several subtasks, each of which has very specific requirements for the perception system. In this paper, we analyze several of these subtasks from the perspective of compute...
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ISBN:
(纸本)0780344235
The task of autonomous navigation comprises several subtasks, each of which has very specific requirements for the perception system. In this paper, we analyze several of these subtasks from the perspective of computer vision, including (i) obstacle detection, (ii) terrain reconstruction, (iii) convoying, (iv) collision detection, and (v) road recognition. We delineate the issues associated with each subtask and outline algorithms to address each issue. Finally, we address the issue of implementation. We present the vFE-200 as a very powerful imageprocessing platform specifically designed for the implementation of autonomous mobility vision algorithms. We describe the architecture of the system, and how several key features make it ideally suited for hosting several government-sponsored autonomous mobility platforms such as MDARS-E, AUTONAv and Demo III.
image segmentation requires processing of a huge volume of data. It is therefore necessary, for their implementation in industrial computer controlled systems, to search for straightforward algorithms. Presently, lite...
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image segmentation requires processing of a huge volume of data. It is therefore necessary, for their implementation in industrial computer controlled systems, to search for straightforward algorithms. Presently, literature offers a lot of gray-tone image segmentation techniques, but few of them attend to color image segmentation. This paper presents a co-operative strategy within a multi-resolution color image segmentation, which attempt to extract the meaningful information (regions and boundaries), then fuse these two approaches in order to achieve an accurate, robust and suitable segmentation. A blob filling coloration algorithm allows to design, from the segmented image, a synthesis image which appears as a simplified but faithfull copy with a chosen resolution of the original image. This process is induced by approach of the human psychovisual system of perception, render to the sharp edges, strong contrasts and large areas of color. It gives good results when applied on natural scenes, like a bunch of flowers, or on artificial scenes, like a set of building blocks. As possible, we use the coding vocabulary of R.M. Haralick.((1)) (C) 1997 Pattern Recognition Society. Published by Elsevier Science Ltd.
An emerging feature of multimedia and tele-presence systems is stereo imagery. Stereo images provide an enhanced sense of presence, and have been found to be operationally useful in tasks requiring remote manipulation...
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An emerging feature of multimedia and tele-presence systems is stereo imagery. Stereo images provide an enhanced sense of presence, and have been found to be operationally useful in tasks requiring remote manipulation or judgment of spatial relationships. A conventional stereo system with a single left-right pair needs twice the raw data as a monoscopic imaging system. A multi-view stereo system may require hundreds of times as much. As a result there has been increasing attention given to image compression methods specialized to stereo pairs. Most of this work has focused on disparity-compensated residual coding where one view is used to predict another, and the difference is coded. Much of this work has concentrated on improving the disparity compensation process and codes the residual image similarly to a monoscopic image. As this paper will show, the disparity-compensated residual image differs in important ways from a conventional monoscopic image. The residual image has different correlation characteristics, and is composed primarily of strong vertical-direction edge components surrounded by large areas of near zero intensity. This paper demonstrates these properties, both theoretically and experimentally, and outlines how they might be exploited in designing compression algorithms. Other papers demonstrate that greater than 2 dB improvement is possible when exploiting such characteristics for stereo image compression. (C) 1998 Published by Elsevier Science B.v. All rights reserved.
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