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International Conference on Pattern Recognition

作者： G. Langs P. Radeva D. Rotger F. Carreras Insitute for Computer Graphics and Vision Graz University of Technology Graz Austria Pattern Recognition and Image Processing Group Vienna University of Technology Vienna Austria Computer Vision Center Universitat Autònoma de Barcelona Bellaterra Spain Hospital St. Pau Barcelona Spain

In this paper, we address the problem of multimodal registration of coronary vessels by developing a 3D parametrical model of vessel trees from computer tomography data and registering it to angiography images during intervention. Thus, the interventionist takes profit from 3D data otherwise only available before the intervention. This facilitates orientation in ambiguous radiographs, interactive visualization of all vessel structures to estimate their mutual position and navigation within the vessel system and ultimately reduces the radiation the patient and the physicians are exposed to. The model is build by exploring the branching vessel tree starting from a single position and successively expanding through the vessels guided by a local deformable surface. The result is a tree of cylindrical segments each adapted to the vessel walls that is registered to angiography images in a fast and robust way. Validation on 8 patients confirms the robustness of our method.

关键词： X-ray imaging Computed tomography Robustness Angiography image segmentation image reconstruction Distortion measurement Tree graphs Data visualization Radio navigation

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Protocol for streaming compressed 3-D animations over lossy channels

Protocol for streaming compressed 3-D animations over lossy ...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： G. Al-Regib Y. Altunbasak J. Rossignac R. Mersereau Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA Graphics Visualization and Usability Center Georgia Institute of Technology Atlanta GA USA Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA USA

We propose a protocol for efficient streaming of 3-D animations over lossy channels. In order to improve the expected quality on the client's side, we first transmit a crude model of the 3-D mesh, of its texture, and of its immediate evolution. We endow this data with significant error-protection against transmission error. Then we transmit a series of upgrades that refine the accuracy of the model and/or of the animation. These are encoded with lower levels of error protection that is proportional to their impact on the quality of the upgraded animation. We propose the following types of upgrade chunks: selection of a subset of vertices, adjustments of the accuracy of the positions of the selected vertices, connectivity refinements, motion adjustments of the selected subset of vertices, adjustments of the accuracy of the texture coordinates of the selected vertices, and upgrade of the quality of the texture. Finally, given the allocated bit-budget, we determine the optimal number of both source and channel coding bits assigned for each chunk to maximize the animation quality on the client's side. The optimization takes into account both the bandwidth and the error characteristics of the channel.

关键词： Protocols Animation Internet Streaming media Bandwidth Layout image coding Visualization Electronic mail Protection

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An unequal error protection method for progressively compressed 3-D meshes

An unequal error protection method for progressively compres...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Ghassan Al-Regib Yucel Altunbasak Jarek Rossignac Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA USA Graphics. Visualization and Usability Center Georgia Institute of Technology Atlanta GA USA

In this paper, we present a packet-loss resilient 3-D graphics transmission system that is scalable with respect to both channel bandwidth and channel error characteristics. The algorithm trades off source coding efficiency for increased bit-stream error resilience to optimize the decoded mesh quality on the client side. It uses the Compressed Progressive Mesh (CPM) algorithm to generate a hierarchical bit-stream representing different levels of details (LODs). We assign optimal forward error correction (FEC) code rates to protect different parts of the bit-stream differently. These optimal FEC code rates are determined theoretically via a distortion function that accounts for: the channel packet loss rate, the nature of the encoded 3-D mesh and the error protection bit-budget. We present experimental results, which show that with our unequal error protection (UEP) optimal approach, the decoded mesh quality degrades more gracefully (compared to either no error protection (NEP) or equal error protection (EEP) methods) as the packet loss rate increases.

关键词： Decoding Indexes Extraterrestrial measurements Context Particle measurements Atmospheric measurements Robustness

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A joint source and channel coding approach for progressively compressed 3-D mesh transmission

A joint source and channel coding approach for progressively...

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IEEE International Conference on image Processing

作者： G. Al-Regib Y. Altunbasak J. Rossignac Center for Signal & Image Process. Georgia Inst. of Technol. Atlanta GA USA Center for Signal and Image Processing Georgia Institute of Technology Atlanta GA USA Graphics Visualization and Usability Center Georgia Institute of Technology Atlanta GA USA

In this paper, we present an unequal error protection method for packet-loss resilient transmission of progressively compressed 3D meshes. The proposed method is based on a source and channel coding approach where we set up a theoretical framework for the overall system by which the channel packet loss behavior and the channel bandwidth can be directly related to the decoded mesh quality at the receiver. In particular, we develop a statistical distortion measure and optimize it to compute the best combination of (i) the number of triangles to transmit, (ii) the total number of channel coding bits, and (iii) the distribution of these error-protection bits among the transmitted layers in order to maximize the expected decoded mesh quality at the receiver. The proposed method differs from the earlier approaches in two major aspects: (i) determination of the number of channel coding bits (C) and (ii) the approach of reducing the source rate in order to accommodate for channel coding bits. When the proposed method is used to transmit a typical 3D mesh over a channel with a 10% packet loss rate, the distortion (measured using the Hausdorff distance between the original and the decoded overly sampled meshes) is reduced by 50% compared to the case when no error protection is applied.

关键词： Channel coding Decoding Distortion measurement Error correction codes Bandwidth Particle measurements Distributed computing Propagation losses Rate distortion theory Loss measurement

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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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Sinuscone @@-athetaphi algorithm for human arm animation 4

Sinuscone @@-athetaphi algorithm for human arm animation

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4th IEEE International Conference on Information Visualisation, IV 2000

作者： Jing, Huang Prakash, Edmond C. Center for Graphics and Image Technology Nanyang Technological University Singapore639798 Singapore School of Computer Engineering Nanyang Technological University Singapore639798 Singapore

ISBN: (纸本)0769507433

Arm animation algorithms are o fen categorized by their constraint expansion strategy. One option is the geometric bounding polygon-cone strategy, a simple containment search strategy that traverses the search space in the order in which successor bounding polygon edges are generated. An alternative is the Thetaphi-cone strategy, which was designed to make it possible ro use domain-speci$c heuristic information. By exploring promising parts of the cone space Jirst, Thetaphi-conealgorithms generally are more eficient than polygon-cone algorithms. © 2000 IEEE.

关键词： Animation

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SinusCone /spl Theta//spl Phi/-a ThetaPhi algorithm for human arm animation

SinusCone /spl Theta//spl Phi/-a ThetaPhi algorithm for huma...

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International Conference on Information Visualisation (IV)

作者： Huang Jing E.C. Prakash Center for Graphics and Image Technology Nanyang Technological University Singapore School of Computer Engineering Nanyang Technological University Singapore

Arm animation algorithms are often categorized by their constraint expansion strategy. One option is the geometric bounding polygon-cone strategy, a simple containment search strategy that traverses the search space in the order in which successor bounding polygon edges are generated. An alternative is the ThetaPhi-cone strategy, which was designed to make it possible to use domain-specific heuristic information. By exploring promising parts of the cone space first, ThetaPhi-cone algorithms generally are more efficient than polygon-cone algorithms.

关键词： Humans Animation Shoulder Space technology Databases graphics Motion control Shape Interpolation Biological system modeling

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Distance learning into the 21st century

Distance learning into the 21st century

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1999 ASEE Annual Conference and Exposition: Engineering Education to Serve the World

作者： Hayes, Monson H. Harvel, Lonnie Sch. of Elec. and Comp. Engineering Georgia Institute of Technology Atlanta GA 30332 Sch. of Elec. and Comp. Engineering Comp. Enhanced Educational Services Ctr. Sign./Image Proc. and Graphics Visualization and Usability Center Georgia Tech.

The Georgia Institute of technology is in a unique position of having a campus located across the Atlantic in the heart of the Lorraine region of France. Offering masters degree programs in electrical and mechanical engineering, Georgia Tech Lorraine (GTL) must deliver more courses than can be staffed by resident faculty. Consequently, GTL must offer courses by videotaping courses that are taught by faculty at the Georgia Tech campus in Atlanta. Delivering courses by videotape, however, is relatively expensive, introduces a two week delay between the two sections of the courses, and is not the most convenient method of course delivery for the student. The internet, however, offers some unique opportunities for the remote delivery of courses. Over the last eighteen months, we have been delivering graduate courses between France and the U.S. using streaming media. In this paper, we describe the approaches that we have used, enumerate the investment in time and resources necessary to deliver these courses, and give some predictions for what we envision internet delivery of courses will be like in the 21st century.

关键词： Distance education

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ATTACKING UNSOLVED PROBLEMS IN VISUALIZATION OF SCIENTIFIC-DATA - A PANEL PRESENTATION

ATTACKING UNSOLVED PROBLEMS IN VISUALIZATION OF SCIENTIFIC-D...

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CONF ON EXTRACTING MEANING FROM COMPLEX DATA : PROCESSING, DISPLAY, INTERACTION

作者： ANDERSON, HS ANDREWS, LT BUTURLA, EM DUNCAN, GC HESSELINK, L Ohio Supercomputer Graphics Project Ohio Supercomputer Center 1224 Kinnear Rd. Columbus 43212 OH United States Medical College of Ohio Image Analysis Research Center C.S. 10008 Toledo 43699 OH United States IBM Technology Simulation Burlington 05452 VT United States Department of Physics and Astronomy Bowling Green State University Bowling Green 43403 OH United States Department of Aero/Astronautics and Electrical Engineering Stanford University Stanford 94305 CA United States

ISBN: (纸本)0819403067

There are some "Grand Challenges" of data visualization which scientists in every application domain confront at one time or another. For example, how to access large volumes of data, how to isolate the "important" pieces of information, how to map scientific data to primitives suitable for graphical algorithms, how to achieve the speed of useful interaction, why won't off-the-shelf software do what I need it to do, how to make hardcopy, etc., are just some of the common problems. This panel session addresses issues like these/from the point of view of the scientist who uses visualization as a research tool. Each panelist was invited to submit a short "position paper", which is reproduced here. © 1990 Proceedings of SPIE - The International Society for Optical Engineering. All rights reserved.

关键词： Visualization

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Data Acquisition and Modeling in Clinical Electrooculography

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IFAC Proceedings Volumes 1984年第2期17卷 3065-3070页

作者： W. Poelzleitner A.U. Meyer G.M. Stephens Electrical Engineering Department New Jersey Institute of Technology 323 High Street Newark NJ 07102 USA Now with Research Center for Digital Image Processing and Graphics Wastiangasse 6 8010 Graz Austria Department of Ophthalmology University of Medicine and Dentistry and Eye Institute of New Jersey 15 South 9 Street Newark NJ 07107 USA

Electrooculography (EOG) is used in clinical ophthalmology to measure the time response of the corneoretinal potential (CRP) to changes in light intensity. A system for automatic data acquisition and model estimation has been developed. The data acquisition is performed on a microprocessor based instrument, which supervises the EOG test, measures the potential and, after completion of the test, transfers the results to a mainframe computer. Nonlinear curve fitting is used for the estimation of the model parameters. Several models are considered.

关键词： Biomedical electrooculography electrophysiology identification medical data acquisition medical data reduction and analysis medical information processing physiological models

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