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parallel and distributed methods for image processing IV

作者： Alto, Hilary Rangayyan, Rangaraj M. Gavrilov, Dmitri Univ of Calgary Calgary Canada

A multi-tolerance region-growing algorithm for automatically detecting and circumscribing calcifications in digitized mammographic images was developed. Independent studies comparing various segmentation methods showed that the multi-tolerance technique works well. However, the method is computationally expensive due to the checking of the validity of the grown region at every tolerance level until the optimal region is obtained for each calcification. Furthermore, a single mammogram may contain as many as a few hundred calcifications. In order to reduce the processing time, the calcification detection algorithm was implemented on a cluster of processors using the message passing interface. In the parallel implementation, the master processor partitions the image via histogram thresholding, and sends seed pixels to the slaves to execute the multi-tolerance region-growing procedure. The slave processors grow regions, calculating a few shape parameters at each tolerance level. The parameters are used to compute distance measures which are compared until the minimum change in distance is achieved. Shape factors are then computed to describe the roughness of each region's final boundary and returned to the master processor. Initial trials have shown a speedup factor of three to eight when comparing the use of 13 slave processors to the use of one slave processor.

关键词： Medical imaging

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distributed memory prestack Kirchhoff time migration: parallelization and scalability

Distributed memory prestack Kirchhoff time migration: Parall...

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2000 Society of Exploration Geophysicists Annual Meeting, SEG 2000

作者： Hellman, Kevin J. IBM United States

Kirchhoff 3D prestack migration is a seismic data processing application which produces a subsurface image of the earth by integrating large amounts of recorded seismic data. It is an industry staple (particularly the "time migration" variant), and is very computationally intensive, requiring the use of supercomputers to produce results in a timeframe of weeks or months. One type of supercomputer is based on a clustering of many smaller computers, each with their own memory and some sort of network connection to each other. These machines - distributed memory parallel computers - provide a cost-effective solution for commercial Kirchhoff migration, provided the algorithms can be efficiently parallelized. parallel scalability is crucial, so that adding more processors will reduce the time to completion accordingly. There are many ways to implement a parallel Kirchhoff prestack time migration. Three basic strategies are discussed, and their parallel scalability analyzed. The impact of operator antialiasing on parallel performance is considered for two common methods of antialiasing protection. A timing model of the parallel computation is developed, and used to predict runtimes for a production sized migration problem on a given number of processors. Based on these predictions, the best approach for parallelization is a master/slave model with dynamic distribution of the data traces to the nodes. The bulk of processor memory is used to hold individual copies of the image volume, and antialiasing is accomplished with multiple banks of bandpass filtered data. © SEG 2000. All rights reserved.

关键词： Supercomputers

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parallel computation of radio listening rates

Parallel computation of radio listening rates

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parallel and distributed methods for image processing IV

作者： Mazzariol, M. Gennart, B. Hersch, R.D. Gomez, Manuel Balsiger, Peter Pellandini, F. Leder, Markus Wuthrich, Daniel Feitknecht, Juerg Ecole Polytechnique Federale de Lausanne Lausanne Switzerland

Obtaining the listening rates of radio stations in function of time is an important instrument for determining the impact of publicity. Since many radio stations are financed by publicity, the exact determination of radio listening rates is vital to their existence and to their further development. Existing methods of determining radio listening rates are based on face to face interviews or telephonic interviews made with a sample population. These traditional methods however require the cooperation and compliance of the participants. In order to significantly improve the determination of radio listening rates, special watches were created which incorporate a custom integrated circuit sampling the ambient sound during a few seconds every minute. Each watch accumulates these compressed sound samples during one full week. Watches are then sent to an evaluation center, where the sound samples are matched with the sound samples recorded from candidate radio stations. The present paper describes the processing steps necessary for computing the radio listening rates, and shows how this application was parallelized on a cluster of PCs using the CAP Computer-aided parallelization framework. Since the application must run in a production environment, the paper describes also the support provided for graceful degradation in case of transient or permanent failure of one of the system's components. The parallel sound matching server offers a linear speedup up to a large number of processing nodes thanks to the fact that disk access operations across the network are done in pipeline with computations.

关键词： parallel processing systems

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parallel DSP implementation of wavelet transform in image compression

Parallel DSP implementation of wavelet transform in image co...

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IEEE International Symposium on Circuits and Systems (ISCAS)

作者： K. Haapala P. Kolinummi T. Hamalainen J. Saarinen Digital and Computer Systems Laboratory Tampere University of Technology Tampere Finland

A parallel implementation of the 2D discrete wavelet transform on a distributed memory multiprocessor system called PARNEU is presented. The mapping has been chosen with consideration to load balancing and communication methods in order to achieve the best possible scalability and performance in transforming one single image. Detailed performance figures are included. Experimental results show that significant parallel speedup is reached with this mapping.

关键词： Digital signal processing Wavelet transforms image coding Discrete wavelet transforms Discrete transforms Concurrent computing Shape Video coding Computer architecture Field programmable gate arrays

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High performance medical image processing in client/server-environments

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COMPUTER methods AND PROGRAMS IN BIOMEDICINE 1999年第3期58卷 207-217页

作者： Mayer, A Meinzer, HP H0100 Deutsch Krebsforschungszentrum Dept Med & Biol Informat D-69120 Heidelberg Germany

As 3D scanning devices like computer tomography (CT) or magnetic resonance imaging (MRI) become more widespread, there is also an increasing need for powerful computers that can handle the enormous amounts of data with acceptable response limes. We describe an approach to parallelize some of the more frequently used image processing operators on distributed memory architectures. It is desirable to make such specialized machines accessible on a network, in order to save costs by sharing resources. We present a client/server approach that is specifically tailored to the interactive work with volume data. Our image processing server implements a volume visualization method that allows the user to assess the segmentation of anatomical structures. We can enhance the presentation by combining the volume visualizations on a viewing station with additional graphical elements, which can be manipulated in real-time. The methods presented were verified on two applications for different domains. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.

关键词： client/server environments image processing volume visualization hybrid visualization parallel processing

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Design of fast algorithms for projections through matrix decomposition

Design of fast algorithms for projections through matrix dec...

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Conference on parallel and distributed methods for image processing III

作者： Li, HZ Shi, HC Univ Missouri Dept Comp Sci & Comp Engn Columbia MO 65212 USA

ISBN: (纸本)0819433039

Projection is a frequently used process in image processing and visualization. In volume graphics, projection is used to render the essential content of a 3D volume onto a 2D image plane. For Radon transform, projection is used to transform the image space into a parameter space. In this paper, we propose a matrix decomposition method called identity-plus-row decomposition for designing fast algorithms for projections. By applying this method, we solve the data redistributed problem due to the irregular data access patterns present in those applications on SIMD mesh-connected computers, developing fast algorithms for volume rendering and Radon transform an SIMD mesh-connected computers.

关键词： image processing matrix decomposition parallel algorithm mesh connected computers

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Programming tool for real-time image processing on a distributed system

Programming tool for real-time image processing on a distrib...

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Proceedings of the 1999 parallel and distributed methods for image processing III

作者： Arita, Daisaku Hamada, Yoshio Taniguchi, Rin-ichiro Kyushu Univ Japan

A real-time distributed image processing system requires data transfer, synchronization and error recovery. However, it is difficult for a programmer to describe these mechanisms. To solve this problem, we are developing a programming tool for real-time image processing on a distributed system. Using the programming tool, a programmer indicates only data flow between computers and image processing algorithms on each computer. In this paper, we outline specifications of the programming tool and show sample programs on the programming tool.

关键词： Computer aided software engineering

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parallel implementation of the Karhunen-Loeve procedure for image recognition

Parallel implementation of the Karhunen-Loeve procedure for ...

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Proceedings of the 1999 parallel and distributed methods for image processing III

作者： Liu, Haisong Wu, Minxian Jin, Guofan He, Qingsheng Yan, Yingbai Tsinghua Univ Beijing China

The Karhunen-Loeve(K-L) transform is very useful in image representation and classification. However, the parallel implementation of it through some optical methods have rarely been investigated. In this paper, we constructed a photorefractive crystal based optical processor and implemented the time-consuming projection and operations of the K-L transform in parallel so that the speed of the image processing can be greatly improved. In our approach, a set of eigenimages extracted from a large number of training images by K-L transform are stored in the crystal by using the two-wave mixing technique. When any view image inputs the processor, spatially separated beams with different light intensities are obtained in parallel. The intensity of each beam just represents the projection result between the input image and each eigenimage. The high speed can sufficiently demonstrate the advantage of the optical computing based parallel architecture for image processing.

关键词： image processing

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Automatic derivation of programs for image processing from natural language descriptions

Automatic derivation of programs for image processing from n...

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Conference on parallel and distributed methods for image processing III

作者： Ren, F Zaima, Y Hiroshima City Univ Fac Informat & Sci Hiroshima Japan

ISBN: (纸本)0819433039

In this paper we describe AIDPG, an interactive prototype system, which derives computer programs from their natural language descriptions. AIDPG shows how to analyze natural language, resolve ambiguities using knowledge, and generates programs. AIDPG consists of a natural language input model (NLI-Model), a natural language analysis model (NLA-Model), a program generation model (PGG-Model) and a human machine interface control model (HMC-Model). The PGG model has three sub-models, program structure manage sub-model, a data structure and type manage sub-model, and program base manage sub-model. We used an arithmetic problem, which, described in Japanese, was passed to AIDPG and got run-possible C programs. Although AIDPG is basic currently we got a significant result.

关键词： automatic derivation of programs natural language descriptions knowledge ambiguity

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A method to solve the scalability problem in managing massively parallel processing on the Internet 7

A method to solve the scalability problem in managing massiv...

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7th Euromicro Workshop on parallel and distributed processing (PDP 99)

作者： Yero, EJH Henriques, MAA UNICAMP DCA FEEC BR-13083970 Campinas SP Brazil

ISBN: (纸本)0769500595

A set of computers connected by the Internet can be seen as a MIMD virtual parallel computer with distributed memory. We call such a computer a Massively parallel Virtual Computer (MPVC). The implementation of an MPVC will be feasible in rite next few years, as new technologies bring to Internet communication speeds undreamed of nowadays. Problems such as Monte Carlo simulations and image processing and generation are good candidates to take advantage of MPVCs, since they can use practically: all rite computing power they can get. Massively parallel processing on the I,Internet introduces the problem of scalability that is, how to administrate efficiently a large number of computers and an even larger number of tasks running in them. Previous approaches either do not scale well or let the programmer solve the problem by himself This paper explains the Dynamic Virtual Hypercubes, a structure created to logically organize an MPVC. Dynamic Virtual Hypercubes provide a scalable and efficient way to handle a large number of computers and tasks, since they can adapt to changes it? workload and number of available machines.

关键词： Monte Carlo methods

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