Driven by the rapidly increasing demand for audio-visual applications, digital video compression technology has become a mature field, offering several available products based on both hardware and software implementa...
详细信息
Driven by the rapidly increasing demand for audio-visual applications, digital video compression technology has become a mature field, offering several available products based on both hardware and software implementations. Taking advantage of spatial, temporal, and statistical redundancies in video data, a video compression system aims to maximize the compression ratio while maintaining a high picture quality. Despite the tremendous progress in this area, video compression remains a challenging research problem due to its computational requirements and also because of the need for higher picture quality at lower data rates. Designing efficient coding algorithms continues to be a prolific area of research. For circumvent the computational requirement, researchers has resorted to parallel processing with a variety of approaches using dedicated parallel vLSI architectures as well as software on general-purpose available multiprocessor systems. Despite the availability of fast single processors, parallel processing helps to explore advancedalgorithms and to build more sophisticated systems. This paper presents an overview of the recent research in video compression using parallel processing. The paper provides a discussion of the basic compression techniques, existing video coding standards and various parallelization approaches. Since video compression is multi-step in nature using various algorithms, parallel processing can be exploited at an individual algorithm or at a complete system level. The paper covers a broad spectrum of such approaches, outlining the. basic philosophy of each approach and providing examples. We contrast these approaches when possible, highlight their pros and cons, and suggest future research directions. While the emphasis of this paper is on software-based methods, a significant discussion of hardware and vLSI is also included. (C) 2002 Published by Elsevier Science B.v.
The concern here is of retrieving damped harmonics and polynomial phase signals in the presence of additive noise. The damping function is not limited to the exponential model, and in certain cases, the additive noise...
详细信息
ISBN:
(纸本)0819416207
The concern here is of retrieving damped harmonics and polynomial phase signals in the presence of additive noise. The damping function is not limited to the exponential model, and in certain cases, the additive noise does not have to be white. Three classes of algorithms are presented, namely DFT based, Kumaresan-Tufts type extensions, and subspace variants including the MUSIC algorithm. Preference should be based on the available data length and frequency separations. In addition, retrieval of self coupled damped harmonics, which may be present when nonlinearities exist in physical systems, is investigated. Simulation examples illustrate main points of the paper.
Sonar array systems in the highly cluttered undersea environment require new and enhanced signal-processingalgorithms and sophisticated architectures to meet the stringent real-time and reliability mission requiremen...
Sonar array systems in the highly cluttered undersea environment require new and enhanced signal-processingalgorithms and sophisticated architectures to meet the stringent real-time and reliability mission requirements. These demands present significant challenges in terms of computational complexity and dependability; and necessitate the development and use of high-performance computing techniques and advancedsignal-processingalgorithms. Our study introduces novel parallel and fault-tolerant techniques for adaptive matched-field processing (MFP) which we investigated on distributed array systems along with high-performance networking and distributed computing architectures. We developed the parallel algorithms for adaptive MFP to satisfy the computational and memory requirements not readily supported by cutting-edge, high-performance, single-processor systems. We proposed robust MFP algorithms to compensate for the performance degradation presented by sensor failures in sonar array systems. We also developed fault-tolerant parallel algorithms characterized by low overhead and fast recovery time to enhance dependability. We implemented the proposed parallel algorithms and fault-tolerant mechanisms on scalable clusters of computers. We compared their performance considering several critical factors such as parallel and fault-tolerant techniques, communication schemes, and processor architectures. Results show that these parallel and fault-tolerant algorithms can provide a feasible solution for real-time, scalable, and highly reliable beamforming implementations on distributed array systems.
We present an algorithm-based fault tolerant scheme for QR decomposition, that extends the well-known Gentleman-Kung-McWhirter triangular systolic array architecture. Assuming that the array is subject to transient fa...
详细信息
ISBN:
(纸本)0819416207
We present an algorithm-based fault tolerant scheme for QR decomposition, that extends the well-known Gentleman-Kung-McWhirter triangular systolic array architecture. Assuming that the array is subject to transient faults, widely separated in time and each affecting a single processor, we give an algorithm that corrects the full triangular array with computational overhead equivalent, on average, to the interpolation of a single extra vector into the data stream.
The Rapid Prototyping of Application Specific signal Processors (RASSP) program has as its goal the dramatic improvement of the process by which signal processors are specified, designed, documented, manufactured, and...
详细信息
ISBN:
(纸本)0819416207
The Rapid Prototyping of Application Specific signal Processors (RASSP) program has as its goal the dramatic improvement of the process by which signal processors are specified, designed, documented, manufactured, and supported. A key part of the RASSP process is the method of architecture selection. An architecture overview is presented, together with a discussion of architecture classification, architecture evaluation factors, and signalprocessing flow. Two important architecture support aspects are briefly discussed: open systems architecture and integrated diagnostics. Recommendations for preferred approaches and rules of thumb for architecture selection are given. Finally, the RASSP architecture selection process is outlined, including a discussion of a standard hardware/software module interface.
Compressed video bitstreams require protection from channel errors in a wireless channel. The three-dimensional (3-D) SPIHT coder has proved its efficiency and its real-time capability in compression of video. A forwa...
详细信息
ISBN:
(纸本)0819441880
Compressed video bitstreams require protection from channel errors in a wireless channel. The three-dimensional (3-D) SPIHT coder has proved its efficiency and its real-time capability in compression of video. A forward-error-correcting (FEC) channel (RCPC) code combined with a single ARQ (automatic-repeat-request) proved to be an effective means for protecting the bitstream. In this paper, the need for ARQ is eliminated by making the 3-D SPIHT bitstream more robust and resistant to channel errors. Packetization of the bitstream and the reorganization of these packets to achieve scalability in bit rate and/or resolution in addition to robustness is demonstrated and combined with channel coding to not only protect the integrity of the packets, but also allow detection of packet decoding failures, so that only the cleanly recovered packets are reconstructed. In extensive comparative tests, the reconstructed video is shown to be superior to that of MPEG-2, with the margin of superiority growing substantially as the channel becomes noisier.
For an assessment of the power quality in power distribution systems, classical Fourier series-based power quality indices are normally employed. The classical Fourier series-based power quality indices assume the per...
详细信息
For an assessment of the power quality in power distribution systems, classical Fourier series-based power quality indices are normally employed. The classical Fourier series-based power quality indices assume the periodicity of the disturbance so that the applications are limited to the harmonics. Hence, it is necessary for us to redefine power quality indices for the "transient" disturbances. In this paper, development of time-frequency based power quality indices are discussed for an assessment of transient power quality. The time and frequency localized information of the transient disturbance signals will be utilized for a new definition of the transient power quality indices. As an example of time-frequency based power quality indices, new definition of transient telephone interference factor has been carefully derived and verified in comparison with traditional telephone interference factor has been carefully derived and verified in comparison with traditional telephone interference factor. Time-frequency based power quality indices allow one to quantify the effects of transient disturbances by time and frequency localized information.
A massively parallel signal and image processing architecture is considered. The architecture is comprised of 2D arrays of cells that simulate the response of retina neurons. The results of simulations are compared to...
详细信息
ISBN:
(纸本)0819416207
A massively parallel signal and image processing architecture is considered. The architecture is comprised of 2D arrays of cells that simulate the response of retina neurons. The results of simulations are compared to previously published experimental results and the system is applied to detection of spatio-temporal features in sequences of images representative of pulse- doppler radar images. By arranging the output layer so that the cells respond to various key input features an array of feature extraction cells can be obtained. The system is characterized by developing an image space to feature space mapping.
Establishing measures for local stationarity is an open problem in the field of time-frequency analysis. One promising theoretical measure, known as the spread, provides a means for quantifying potential correlation b...
详细信息
Establishing measures for local stationarity is an open problem in the field of time-frequency analysis. One promising theoretical measure, known as the spread, provides a means for quantifying potential correlation between signal elements. In this paper we investigate the issue of generalizing techniques developed by the authors to better estimate the spread of a signal. Existing techniques estimate the spread as the rectangular region of support of the associated expected ambiguity function oriented parallel to the axes. By applying Radon Transform techniques we can produce a parameterized model which describes the orientation of the region of support providing tighter estimates of the signal spread. Examples are provided that illustrate the enhancement of the new method.
New efficient structures using the one-hot residue number system (OHRNS) are presented. Normally the RNS uses a binary representation for the residues, though recently there has been renewed interest in the OHRNS, whi...
详细信息
ISBN:
(纸本)0819445584
New efficient structures using the one-hot residue number system (OHRNS) are presented. Normally the RNS uses a binary representation for the residues, though recently there has been renewed interest in the OHRNS, which uses a simple, but novel representation for the residues. The basic component of the OHRNS is the barrel shifter, making the OHRNS suitable for very high speed applications. The first of the new structures presented reduces the power dissipation in OHRNS adder trees. A modification to the normal barrel shifter is proposed, which reduces the power dissipated by as much as 30%. This improvement is obtained through the use of the modified barrel shifter and the appropriate connection of active-low and active-high stages. This overall power reduction offers the possibility of using the OHRNS in place of a typical full adder based tree in high speed DSP applications. A new storage register for one-hot representations is detailed, which overcomes the problem of having to use a large number of registers. A new architecture is presented for fast OHRNS sign detection. Sign detection is complex and slow to perform in the RNS. A mixed radix conversion (MRC) is typically used for sign detection in the OHRNS. The new sign detection architecture is based on a new property of the Chinese Remainder Theorem (CRT) and is significantly faster than the MRC approach for large moduli sets. Simulation results using SPICE are detailed for the new structures.
暂无评论