作者:
R. KurcerenJ.W. ModestinoElectrical
Computer and Systems Engineering Department and Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA
The use of forward error-control (FEC) coding has emerged as a promising approach for real-time transport over ATM networks for cell-loss recovery. The use of an FEC-based transport protocol over networks with bandwid...
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ISBN:
(纸本)0780367111
The use of forward error-control (FEC) coding has emerged as a promising approach for real-time transport over ATM networks for cell-loss recovery. The use of an FEC-based transport protocol over networks with bandwidth constraints, however, is not obvious since FEC coding introduces an overhead which can possibly cause additional cell losses which, furthermore, tend to occur in bursts. In this work, an overall performance evaluation of FEC coding is provided by incorporating the effects of channel coding on the cell-loss characteristics of the network. It is shown that FEC coding with proper selection of channel coding rate can significantly improve the throughput at a multiplexer even under correlated cell-loss situations. We also develop and illustrate an information-theoretic approach for incorporating the effects of FEC coding into well-established queueing theory calculations. This is achieved by solving separately the channel-coding problem for the modeled transmission channel and the queueing problem for the network. The performance of some specific coding designs are shown to approach the information-theoretic predictions with increasing complexity and/or delay.
In this paper, we present a new embedded wavelet image coding system using quadtree splitting and context modeling. It features low computational complexity and high compression efficiency, thanks to joint utilization...
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ISBN:
(纸本)0769510310
In this paper, we present a new embedded wavelet image coding system using quadtree splitting and context modeling. It features low computational complexity and high compression efficiency, thanks to joint utilization of two powerful embedded coding techniques-set partitioning and context modeling. With effective exploitation of strong statistical dependencies among the quadtree nodes built up from subband coefficients, the proposed algorithm substantially improves the coding efficiency of the existing set-partition coders for both lossy and lossless image compression. For example, our experimental results show that the new algorithm respectively outperforms zerotree-based SPIHT and quadtree-based SPECK by 0.7 dB and 1.0 dB at 0.5 bpp on an average.
We investigate the transport of scalable digital video over future third-generation (3G) wireless CDMA cellular systems By considering the resource requirements as the aggregate of the products of source coding rates ...
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We investigate the transport of scalable digital video over future third-generation (3G) wireless CDMA cellular systems By considering the resource requirements as the aggregate of the products of source coding rates and the energy per information bit to noise ratio, we propose a joint source coding and power control (JSCPC) scheme which simultaneously maximizes the quality of the delivered video while minimizing the total resource consumption. We demonstrate the efficacy of this approach using the ITU-T H.263+ video source coder, although the approach is generally applicable to other source coding schemes as well.
In this paper we describe a multi-layered video transport scheme for wireless channels capable of adapting to channel conditions in order to maximize end-to-end quality of service (QoS). This scheme combines a scalabl...
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In this paper we describe a multi-layered video transport scheme for wireless channels capable of adapting to channel conditions in order to maximize end-to-end quality of service (QoS). This scheme combines a scalable H.263+ video source coder with unequal error protection (UEP) across layers. The UEP is achieved by employing different channel codes together with a multiresolution modulation approach to transport the different priority layers. Adaptivity to channel conditions is provided through use of joint source-channel coding (JSCC) which attempts to jointly optimize the source and channel coding rates together with the modulation parameters to obtain the maximum achievable end-to-end QoS for the prevailing channel conditions. Results indicate that this adaptive JSCC scheme employing scalable video encoding together with a multiresolution modulation/coding approach leads to significant improvements in delivered video quality for specified channel conditions. In particular, the approach results in considerably improved graceful degradation properties for decreasing channel SNR.
In this paper, we propose an adaptive stereo matching algorithm to encompass stereo matching problems in projective distortion region. Since the projective distortion region can not be estimated in terms of fixed-size...
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In this paper, we propose an adaptive stereo matching algorithm to encompass stereo matching problems in projective distortion region. Since the projective distortion region can not be estimated in terms of fixed-size block matching algorithm, we tried to use adaptive window warping method in hierarchical matching process to compensate the perspective distortions. In addition, probability theory was adopted to encompass uncertainty of disparity of points over the window in this study. The proposed stereo matching algorithm has been tested on both disparity map and 3D model view. The experimental results show that remarkable improvement is obtained in the projective distortion region.
Visualization of particle traces provides intuitive and efficient means for the exploration and analysis of complex vector fields. The paper presents a method suitable for the real-time visualization of arbitrarily la...
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ISBN:
(纸本)0780372239
Visualization of particle traces provides intuitive and efficient means for the exploration and analysis of complex vector fields. The paper presents a method suitable for the real-time visualization of arbitrarily large time-varying vector fields in virtual environments. We describe an out-of-core scheme in which two distinct pre-processing and rendering components enable real-time data streaming and visualization. The presented approach yields low-latency application start-up times and small memory footprints. The described system was used to implement a "volumetric fog lance," which can emit up to 60000 particles into a flow field while maintaining an interactive frame rate of 60 frames per second. All algorithms were specifically designed to support commodity hardware. The proof-of-concept system is running on a low-cost Linux workstation equipped with a 120 GB E-IDE RAID (redundant array of inexpensive disk) system.
The various institution and developments in the field of computergraphics in Germany is discussed. The German research Foundation( DFG), as recognition of research in computergraphics, sponsors a special interdiscip...
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The various institution and developments in the field of computergraphics in Germany is discussed. The German research Foundation( DFG), as recognition of research in computergraphics, sponsors a special interdisciplinary graduates study program on 3D image analysis and synthesis at the University of Erlangen-Nuremburg. The German Association for Informatics, founded in 1983, brings together about 40 representatives from Universities, colleges and industry that co-ordinate activities form five subgroups specializing in foundations and systems, imaging and visualization, graphical user interfaces, simulation and animation, and geometric modeling. Several companies and forums working in the area of computergraphics are situated in Darmstadt.
Change detection on rasterized data is extremely dependent on accurate radiometric and geometric rectification. The development of processing tools able to minimise these requirements has been recognised since the lat...
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With fast computation and excellent compression efficiency, two embedded coding techniques, zero-tree/-block coding and context modeling of the subband/wavelet coefficients, have been widely utilized for image coding ...
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With fast computation and excellent compression efficiency, two embedded coding techniques, zero-tree/-block coding and context modeling of the subband/wavelet coefficients, have been widely utilized for image coding applications. In this research, we present a new embedded wavelet image coding algorithm with an attempt to combine advantages of these two successful coding schemes. The experimental results show that the proposed algorithm outperforms the respected zero-tree/-block coders, SPIHT and SPECK, in compression efficiency. It is also comparable to the state-of-art JPEG 2000 test coder in PSNR performance while retaining the attractive low-complexity feature of the zeroblock coders.
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