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3rd Joint Eurographics - IEEE TCVG Symposium on Visualization, VisSym 2001

作者： Bartrolí, A. Vilanova Wegenkittl, R. König, A. Gröller, E. Sorantin, E. Institute of Computer Graphics and Algorithms Vienna University of Technology Tiani Medgraph Section of Digital Information and Image Processing Department of Radiology University Hospital Graz Austria

ISBN: (纸本)3211836748

We present a new method to visualize virtual endoscopic views. We propose to flatten the organ by the direct projection of the surface onto a set of cylinders. Two sampling strategies are presented and the introduced distortions are studied. A non-photorealistic technique is presented to enhance the perception of the images. Finally, an approximate but real-time endoscopic fly-through is possible by using the data obtained by the projection technique. © 2001 Eurographics Association. All rights reserved.

关键词： image enhancement

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Linear programming concept visualization

Linear programming concept visualization

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International Conference on Information Visualisation (IV)

作者： J.P. Charalambos E. Izquierdo Image Processing and Computer Graphics Research Laboratory Department of Computer Sciences National University Colombia Department of Electronic Engineering Queen Mary University of London London UK

A visualization scheme as a tool to find the solution of any 3D-linear programming problem is introduced. The presented approach is highly suitable to draw and visualize interactively the feasible region of a given 3D-linear programming problem. It can be used for a better understanding of the solution process when different methods devoted to solve the underlying problem are applied, e.g., the simplex method. The proposed technique comprises sensitive analysis during the solution process and interactive visualization of the feasible region. The analysis leading to the introduced schema also shows that the design of an appropriate and simple vertex representation is crucial to manage any order of degeneracy. To deal with this paradigm and to some extent to formalize it, the concept of adjacency invariance is introduced. Several experiments have been conducted to test and assess the performance of the introduced concepts and techniques.

关键词： Linear programming Visualization Testing computer graphics image processing Appropriate technology Stress Algorithm design and analysis

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Reconstructing surfaces using anisotropic basis functions

Reconstructing surfaces using anisotropic basis functions

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International Conference on computer Vision (ICCV)

作者： Huong Quynh Dinh G. Turk G. Slabaugh Graphics Visualization and Usability CenterCollege of Computing Georgia Institute of Technology USA School of Electrical and Computer Engineering Center for Signal and Image Processing Georgia Institute of Technology USA

ISBN: (纸本)0769511430

Point sets obtained from computer vision techniques are often noisy and non-uniform. We present a new method of surface reconstruction that can handle such data sets using anisotropic basis functions. Our reconstruction algorithm draws upon the work in variational implicit surfaces for constructing smooth and seamless 3D surfaces. Implicit functions are often formulated as a sum of weighted basis functions that are radially symmetric. Using radially symmetric basis functions inherently assumes, however that the surface to be reconstructed is, everywhere, locally symmetric. Such an assumption is true only at planar regions, and hence, reconstruction using isotropic basis is insufficient to recover objects that exhibit sharp features. We preserve sharp features using anisotropic basis that allow the surface to vary locally. The reconstructed surface is sharper along edges and at corner points. We determine the direction of anisotropy at a point by performing principal component analysis of the data points in a small neighborhood. The resulting field of principle directions across the surface is smoothed through tensor filtering. We have applied the anisotropic basis functions to reconstruct surfaces from noisy synthetic 3D data and from real range data obtained from space carving.

关键词： Surface reconstruction Anisotropic magnetoresistance image reconstruction Surface fitting Optical noise Shape Polynomials computer vision Surface emitting lasers Space technology

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Use of FEC coding for real-time transport on ATM networks

Use of FEC coding for real-time transport on ATM networks

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IEEE Workshop on High Performance Switching and Routing

作者： R. Kurceren J.W. Modestino Electrical Computer and Systems Engineering Department and Center for Image Processing Research Rensselaer Polytechnic Institute Troy NY USA

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.

关键词： Forward error correction image coding Transport protocols Channel coding Asynchronous transfer mode Systems engineering and theory Bandwidth Throughput Resource management computer networks

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Embedded image coding using zeroblocks of subband/wavelet coefficients and context modeling

Embedded image coding using zeroblocks of subband/wavelet co...

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Data Compression Conference (DCC)

作者： Shih-Ta Hsiang Center for Image Processing Research and Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

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.

关键词： image coding Wavelet coefficients Context modeling Partitioning algorithms Transform coding image processing Embedded computing Power engineering computing Power engineering and energy Systems engineering and theory

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Transport of scalable video over CDMA wireless networks: a joint source coding and power control approach

Transport of scalable video over CDMA wireless networks: a j...

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IEEE International Conference on image processing

作者： Yee Sin Chan J.W. Modestino Center for Image Processing Research Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

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.

关键词： Multiaccess communication Wireless networks Source coding Power control Video compression Systems engineering and theory Streaming media Silicon compounds image processing Power engineering computing

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Multi-layered video transmission over wireless channels using an adaptive modulation and coding scheme

Multi-layered video transmission over wireless channels usin...

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IEEE International Conference on image processing

作者： Y. Pei J.W. Modestino Center for Image Processing Research Electrical Computer and Systems Engineering Department Rensselaer Polytechnic Institute Troy NY USA

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.

关键词： Modulation coding image coding Signal resolution Video coding Quality of service Constellation diagram Systems engineering and theory Error correction codes Channel coding Degradation

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Adaptive hierarchical stereo matching using object segmentation and window warping

Adaptive hierarchical stereo matching using object segmentat...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Jae-Chul Kim Byoung-Ho Kang Maeng-Sub Cho Color Imaging Research Team Image Processing Department Computer and Software Technology Laboratory Electronics and Telecommunications Research Institute Taejon South Korea

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.

关键词： Object segmentation Optical distortion Uncertainty Cameras Solid modeling Color image processing Laboratories Software algorithms Testing

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Real-time out-of-core visualization of particle traces

Real-time out-of-core visualization of particle traces

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IEEE Symposium on Parallel and Large-Data Visualization and graphics (PVG)

作者： R. Bruckschen F. Kuester B. Hamann K.I. Joy Visualization and Graphics Research Group Center for Image Processing and Integrated Computing Department of Computer Science University of California Davis CA USA Visualization and Interactive Systems Group Department of Electrical and Computer Engineering University of California Irvine CA USA

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.

关键词： Data visualization Computational modeling Computational fluid dynamics Motion pictures Hardware computer graphics Interactive systems image processing computer science image analysis

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computer graphics in Germany

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computer graphics (ACM) 2001年第3期35卷 14-21页

作者： Saupe, Dietmar Alexa, Marc Chesnais, Alain Encarnação, Jose Institut für Informatik Universität Leipzig GRIS Technische Universität Darmstadt University of Leipzig Research Group on Computer Graphics and Image Processing Alias Wavefront 17 bis rue Joseph de Maistre 75018 Paris France Fraunhofer-Institut fuer Graphische Datenverarbeitung Wilhelminenstrasse 7 D-64283 Darmstadt Germany 3D Graphics Computing Department of Computer Science Technische Universität Darmstadt

The various institution and developments in the field of computer graphics in Germany is discussed. The German research Foundation( DFG), as recognition of research in computer graphics, 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 computer graphics are situated in Darmstadt.

关键词： computer graphics

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