Issue 3

Permanent URI for this collection

https://diglib7.eg.org/handle/10.2312/96
EG 2000 Conference Proceedings

BibTeX (Issue 3)
                
@article{
10.1111:1467-8659.00392,

journal = {Computer Graphics Forum},
title = {{
Generating Animatable 3D Virtual Humans from Photographs}},

author = {
Lee, WonSook
 and 
Gu, Jin
 and 
Magnenat-Thalmann, Nadia
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00392}

}
                
@article{
10.1111:1467-8659.00401,

journal = {Computer Graphics Forum},
title = {{
Scene-Graph-As-Bus: Collaboration between Heterogeneous Stand-alone 3-D Graphical Applications}},

author = {
Zeleznik, Bob
 and 
Holden, Loring
 and 
Capps, Michael
 and 
Abrams, Howard
 and 
Miller, Tim
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00401}

}
                
@article{
10.1111:1467-8659.00402,

journal = {Computer Graphics Forum},
title = {{
A Novel Approach Makes Higher Order Wavelets Really Efficient for Radiosity}},

author = {
Cuny, Francois
 and 
Alonso, Laurent
 and 
Holzschuch, Nicolas
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00402}

}
                
@article{
10.1111:1467-8659.00403,

journal = {Computer Graphics Forum},
title = {{
Physically-Based Patination for Underground Objects}},

author = {
Chang, Yao-Xun
 and 
Shih, Zen-Chung
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00403}

}
                
@article{
10.1111:1467-8659.00404,

journal = {Computer Graphics Forum},
title = {{
Real Time, Accurate, Multi-Featured Rendering of Bump Mapped Surfaces}},

author = {
Tarini, M.
 and 
Cignoni, P.
 and 
Rocchini, C.
 and 
Scopigno, R.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00404}

}
                
@article{
10.1111:1467-8659.00405,

journal = {Computer Graphics Forum},
title = {{
Interpolatory ?3-Subdivision}},

author = {
Labsik, U.
 and 
Greiner, G.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00405}

}
                
@article{
10.1111:1467-8659.00407,

journal = {Computer Graphics Forum},
title = {{
Subdivision Surface Tesselation on the Fly using a versatile Mesh Data Structure}},

author = {
Muller, Kerstin
 and 
Havemann, Sven
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00407}

}
                
@article{
10.1111:1467-8659.00408,

journal = {Computer Graphics Forum},
title = {{
Augmented Reality with Back-Projection Systems using Transflective Surfaces}},

author = {
Bimber, Oliver
 and 
Encarnacao, L. Miguel
 and 
Schmalstieg, Dieter
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00408}

}
                
@article{
10.1111:1467-8659.00406,

journal = {Computer Graphics Forum},
title = {{
External Memory View-Dependent Simplification}},

author = {
El-Sana, Jihad
 and 
Chiang, Yi-Jen
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00406}

}
                
@article{
10.1111:1467-8659.00409,

journal = {Computer Graphics Forum},
title = {{
Haptic Cues for Image Disambiguation}},

author = {
Faconti, G.
 and 
Massink, M.
 and 
Bordegoni, M.
 and 
De Angelis, F.
 and 
Booth, S.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00409}

}
                
@article{
10.1111:1467-8659.00410,

journal = {Computer Graphics Forum},
title = {{
Priority-Driven Acoustic Modeling for Virtual Environments}},

author = {
Min, Patrick
 and 
Funkhouser, Thomas
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00410}

}
                
@article{
10.1111:1467-8659.00411,

journal = {Computer Graphics Forum},
title = {{
Robust Motion Watermarking based on Multiresolution Analysis}},

author = {
Kim, Tae-hoon
 and 
Lee, Jehee
 and 
Shin, Sung yong
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00411}

}
                
@article{
10.1111:1467-8659.00393,

journal = {Computer Graphics Forum},
title = {{
Using an Intermediate Skeleton and Inverse Kinematics for Motion Retargeting}},

author = {
Monzani, Jean-Sebastien
 and 
Baerlocher, Paolo
 and 
Boulic, Ronan
 and 
Thalmann, Daniel
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00393}

}
                
@article{
10.1111:1467-8659.00412,

journal = {Computer Graphics Forum},
title = {{
Towards Blind Detection of Robust Watermarks in Polygonal Models}},

author = {
Benedens, Oliver
 and 
Busch, Christoph
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00412}

}
                
@article{
10.1111:1467-8659.00413,

journal = {Computer Graphics Forum},
title = {{
Context-based Space Filling Curves}},

author = {
Dafner, Revital
 and 
Cohen-Or, Daniel
 and 
Matias, Yossi
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00413}

}
                
@article{
10.1111:1467-8659.00415,

journal = {Computer Graphics Forum},
title = {{
The Impulse Graph: A New Dynamic Structure For Global Collisions}},

author = {
Baciu, George
 and 
Keung Wong, Sai
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00415}

}
                
@article{
10.1111:1467-8659.00414,

journal = {Computer Graphics Forum},
title = {{
Realistic Collision Avoidance of Upper Limbs Based on Neuroscience Models}},

author = {
Nebel, Jean-Christophe
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00414}

}
                
@article{
10.1111:1467-8659.00418,

journal = {Computer Graphics Forum},
title = {{
Direct Manipulation and Interactive Sculpting of PDE Surfaces}},

author = {
Du, Haixia
 and 
Qin, Hong
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00418}

}
                
@article{
10.1111:1467-8659.00416,

journal = {Computer Graphics Forum},
title = {{
Graceful Degradation of Collision Handling in Physically Based Animation}},

author = {
Dingliana, John
 and 
O'Sullivan, Carol
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00416}

}
                
@article{
10.1111:1467-8659.00417,

journal = {Computer Graphics Forum},
title = {{
Multiresolution Shape Deformations for Meshes with Dynamic Vertex Connectivity}},

author = {
Kobbelt, Leif P.
 and 
Bareuther, Thilo
 and 
Seidel, Hans-Peter
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00417}

}
                
@article{
10.1111:1467-8659.00420,

journal = {Computer Graphics Forum},
title = {{
Color Distribution - A New Approach to Texture Compression}},

author = {
Ivanov, Denis V.
 and 
Kuzmin, Yevgeniy P.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00420}

}
                
@article{
10.1111:1467-8659.00419,

journal = {Computer Graphics Forum},
title = {{
A Multiresolution Model for Soft Objects Supporting Interactive Cuts and Lacerations}},

author = {
Ganovelli, Fabio
 and 
Cignoni, Paolo
 and 
Montani, Claudio
 and 
Scopigno, Roberto
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00419}

}
                
@article{
10.1111:1467-8659.00394,

journal = {Computer Graphics Forum},
title = {{
Modeling the Motion of Dense Smoke in the Wind Field}},

author = {
Rudolf, Marcin J.
 and 
Raczkowski, Jacek
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00394}

}
                
@article{
10.1111:1467-8659.00421,

journal = {Computer Graphics Forum},
title = {{
An Adaptive Spectral Rendering with a Perceptual Control}},

author = {
Claude Iehl, Jean
 and 
Peroche, Bernard
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00421}

}
                
@article{
10.1111:1467-8659.00422,

journal = {Computer Graphics Forum},
title = {{
Tone Reproduction for Interactive Walkthroughs}},

author = {
Scheel, A.
 and 
Stamminger, M.
 and 
Seidel, H.-P.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00422}

}
                
@article{
10.1111:1467-8659.00423,

journal = {Computer Graphics Forum},
title = {{
Integration of Multidimensional Interaction Devices in Real-Time Computer Graphics Applications}},

author = {
Frohlich, Torsten
 and 
Roth, Marcus
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00423}

}
                
@article{
10.1111:1467-8659.00424,

journal = {Computer Graphics Forum},
title = {{
Web-Based Remote Renderingwith IBRAC (Image-Based Rendering Acceleration and Compression)}},

author = {
Yoon, I.
 and 
Neumann, U.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00424}

}
                
@article{
10.1111:1467-8659.00426,

journal = {Computer Graphics Forum},
title = {{
Interactive High-Quality Maximum Intensity Projection}},

author = {
Mroz, Lukas
 and 
Hauser, Helwig
 and 
Groller, Eduard
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00426}

}
                
@article{
10.1111:1467-8659.00428,

journal = {Computer Graphics Forum},
title = {{
Fast Volume Rendering and Data Classification Using Multiresolution in Min-Max Octrees}},

author = {
Dong, Feng
 and 
Krokos, Meleagros
 and 
Clapworthy, Gordon
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00428}

}
                
@article{
10.1111:1467-8659.00427,

journal = {Computer Graphics Forum},
title = {{
Gradient Estimation in Volume Data using 4D Linear Regression}},

author = {
Neumann, Laszlo
 and 
Csebfalvi, Balazs
 and 
Konig, Andreas
 and 
Groller, Eduard
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00427}

}
                
@article{
10.1111:1467-8659.00425,

journal = {Computer Graphics Forum},
title = {{
Virtual Dunhuang Mural Restoration System in Collaborative Network Environment}},

author = {
Li, Xiangyang
 and 
Lu, Dongming
 and 
Pan, Yunhe
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00425}

}
                
@article{
10.1111:1467-8659.00430,

journal = {Computer Graphics Forum},
title = {{
Collaborative Virtual Simulation Environment for Radiotherapy Treatment Planning}},

author = {
Cai, Wenli
 and 
Walter, Stefan
 and 
Karangelis, Grigorios
 and 
Sakas, Georgios
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00430}

}
                
@article{
10.1111:1467-8659.00429,

journal = {Computer Graphics Forum},
title = {{
Reshaping the Coliseum in Rome: An Integrated Data Capture and Modeling Method at Heritage Sites}},

author = {
Gaiani, Marco
 and 
Balzani, Marcello
 and 
Uccelli, Federico
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00429}

}
                
@article{
10.1111:1467-8659.00395,

journal = {Computer Graphics Forum},
title = {{
Unsteady Flow Visualization by Animating Evenly-Spaced Streamlines}},

author = {
Jobard, Bruno
 and 
Lefer, Wilfrid
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00395}

}
                
@article{
10.1111:1467-8659.00431,

journal = {Computer Graphics Forum},
title = {{
A Video-Based 3D-Reconstruction of Soccer Games}},

author = {
Bebie, T.
 and 
Bieri, H.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00431}

}
                
@article{
10.1111:1467-8659.00432,

journal = {Computer Graphics Forum},
title = {{
Video-based Approach to Human Animation}},

author = {
Lao, Zhiqiang
 and 
Li, Ling
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00432}

}
                
@article{
10.1111:1467-8659.00433,

journal = {Computer Graphics Forum},
title = {{
Representing Animations by Principal Components}},

author = {
Alexa, Marc
 and 
Muller, Wolfgang
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00433}

}
                
@article{
10.1111:1467-8659.00434,

journal = {Computer Graphics Forum},
title = {{
A Vector-based Representation for Image Warping}},

author = {
Froumentin, Max
 and 
Labrosse, Frederic
 and 
Willis, Philip
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00434}

}
                
@article{
10.1111:1467-8659.00435,

journal = {Computer Graphics Forum},
title = {{
Real Time Local Approximation of Deformations using Rotations}},

author = {
Maillot, Jerome
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00435}

}
                
@article{
10.1111:1467-8659.00436,

journal = {Computer Graphics Forum},
title = {{
Motion Balance Filtering}},

author = {
Tak, Seyoon
 and 
Song, Oh-young
 and 
Ko, Hyeong-Seok
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00436}

}
                
@article{
10.1111:1467-8659.00437,

journal = {Computer Graphics Forum},
title = {{
Generating Consistent Motion Transition via Decoupled Framespace Interpolation}},

author = {
Ashraf, G.
 and 
Wong, K. C.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00437}

}
                
@article{
10.1111:1467-8659.00396,

journal = {Computer Graphics Forum},
title = {{
Floating Points: A Method for Computing Stipple Drawings}},

author = {
Deussen, Oliver
 and 
Hiller, Stefan
 and 
Van Overveld, Cornelius
 and 
Strothotte, Thomas
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00396}

}
                
@article{
10.1111:1467-8659.00439,

journal = {Computer Graphics Forum},
title = {{
Surface Reconstruction based on Lower Dimensional Localized Delaunay Triangulation}},

author = {
Gopi, M.
 and 
Krishnan, S.
 and 
Silva, C.T.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00439}

}
                
@article{
10.1111:1467-8659.00440,

journal = {Computer Graphics Forum},
title = {{
An Interactive Approach to Point Cloud Triangulation}},

author = {
Kobbelt, Leif P.
 and 
Botsch, Mario
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00440}

}
                
@article{
10.1111:1467-8659.00438,

journal = {Computer Graphics Forum},
title = {{
Automatic Surface Reconstruction from Point Sets in Space}},

author = {
Attene, Marco
 and 
Spagnuolo, Michela
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00438}

}
                
@article{
10.1111:1467-8659.00442,

journal = {Computer Graphics Forum},
title = {{
Integrating Occlusion Culling and Levels of Detail through Hardly-Visible Sets}},

author = {
Andujar, Carlos
 and 
Saona-Vazquez, Carlos
 and 
Navazo, Isabel
 and 
Brunet, Pere
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00442}

}
                
@article{
10.1111:1467-8659.00443,

journal = {Computer Graphics Forum},
title = {{
Directional Discretized Occluders for Accelerated Occlusion Culling}},

author = {
Bernardini, Fausto
 and 
Klosowski, James T.
 and 
El-Sana, Jihad
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00443}

}
                
@article{
10.1111:1467-8659.t01-1-00444,

journal = {Computer Graphics Forum},
title = {{
Colour Section}},

author = {},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.t01-1-00444}

}
                
@article{
10.1111:1467-8659.00441,

journal = {Computer Graphics Forum},
title = {{
Efficient Algorithms for Computing Conservative Portal Visibility Information}},

author = {
Jimenez, W. F. H.
 and 
Esperanca, C.
 and 
Oliveira, A. A. F.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00441}

}
                
@article{
10.1111:1467-8659.00398,

journal = {Computer Graphics Forum},
title = {{
LCTS: Ray Shooting using Longest Common Traversal Sequences}},

author = {
Havran, V.
 and 
Bittner, J.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00398}

}
                
@article{
10.1111:1467-8659.00397,

journal = {Computer Graphics Forum},
title = {{
Automatic Generation of Virtual Woodblocks and Multicolor Woodblock Printing}},

author = {
Mizuno, S.
 and 
Kasaura, T.
 and 
Okouchi, T.
 and 
Yamamoto, S.
 and 
Okada, M.
 and 
Toriwaki, J.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00397}

}
                
@article{
10.1111:1467-8659.00399,

journal = {Computer Graphics Forum},
title = {{
Modelling virtual cities dedicated to behavioural animation}},

author = {
Thomas, Gwenola
 and 
Donikian, Stephane
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00399}

}
                
@article{
10.1111:1467-8659.00400,

journal = {Computer Graphics Forum},
title = {{
Binding Virtual Environments to Toolkit Capabilities}},

author = {
Smith, Shamus P.
 and 
Duke, David J.
},
year = {
2000},

publisher = {
Blackwell Publishers Ltd and the Eurographics Association},


ISSN = {1467-8659},

DOI = {
10.1111/1467-8659.00400}

}

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Recent Submissions

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    Generating Animatable 3D Virtual Humans from Photographs
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Lee, WonSook; Gu, Jin; Magnenat-Thalmann, Nadia
    We present an easy, practical and efficient full body cloning methodology. This system utilizes photos taken from the front, side and back of a person in any given imaging environment without requiring a special background or a controlled illuminating condition. A seamless generic body specified in the VRML H-Anim 1.1 format is used to generate an individualized virtual human. The system is composed of two major components: face-cloning and body-cloning. The face-cloning component uses feature points on front and side images and then applies DFFD for shape modification. Next a fully automatic seamless texture mapping is generated for 360? coloring on a 3D polygonal model. The body-cloning component has two steps: (i feature points specification, which enables automatic silhouette detection in an arbitrary background (ii two-stage body modification by using feature points and body silhouette respectively. The final integrated human model has photo-realistic animatable face, hands, feet and body. The result can be visualized in any VRML compliant browser.
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    Scene-Graph-As-Bus: Collaboration between Heterogeneous Stand-alone 3-D Graphical Applications
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Zeleznik, Bob; Holden, Loring; Capps, Michael; Abrams, Howard; Miller, Tim
    We describe the Scene-Graph-As-Bus technique (SGAB), the first step in a staircase of solutions for sharing software components for virtual environments. The goals of SGAB are to allow, with minimal effort, independently-designed applications to share component functionality; and for multiple users to share applications designed for single users.This paper reports on the SGAB design for transparently conjoining different applications by unifying the state information contained in their scene graphs. SGAB monitors and maps changes in the local scene graph of one application to a neutral scene graph representation (NSG), distributes the NSG changes over the network to remote peer applications, and then maps the NSG changes to the local scene graph of the remote application. The fundamental contribution of SGAB is that both the local and remote applications can be completely unaware of each other; that is, both applications can interoperate without code or binary modification despite each having no knowledge of networking or interoperability.
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    A Novel Approach Makes Higher Order Wavelets Really Efficient for Radiosity
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Cuny, Francois; Alonso, Laurent; Holzschuch, Nicolas
    Since wavelets were introduced in the radiosity algorithm 5, surprisingly little research has been devoted to higher order wavelets and their use in radiosity algorithms. A previous study 13 has shown that wavelet radiosity, and especially higher order wavelet radiosity was not bringing significant improvements over hierarchical radiosity and was having a very important extra memory cost, thus prohibiting any effective computation. In this paper, we present a new implementation of wavelets in the radiosity algorithm, that is substantially different from previous implementations in several key areas (refinement oracle, link storage, resolution algorithm). We show that, with this implementation, higher order wavelets are actually bringing an improvement over standard hierarchical radiosity and lower order wavelets.
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    Physically-Based Patination for Underground Objects
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Chang, Yao-Xun; Shih, Zen-Chung
    Although current photorealistic rendering techniques can produce very impressive images, the rendered objects are often too clean and shiny. Thus, the resulting images look unnatural. This paper proposes a physically-based model to simulate the appearance of patinas on ancient Chinese bronzes. Buried in the soil for thousands of years, many patinas are found on the surface of ancient bronzes as a result of the aging process and the physical and chemical conditions of the soil environment. The development of patinas is modulated herein by L-systems according to tendencies based on the environmental factors and object geometry. The tendencies are employed to represent the accumulative effect of all factors on patination. The proposed model can be extended to simulate a variety of metallic patinas including the ancient Chinese bronzes discovered at San-hsing-tui, Sichuan, China.
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    Real Time, Accurate, Multi-Featured Rendering of Bump Mapped Surfaces
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Tarini, M.; Cignoni, P.; Rocchini, C.; Scopigno, R.
    We present a new technique to render in real time objects which have part of their high frequency geometric detail encoded in bump maps. It is based on the quantization of normal-maps, and achieves excellent result both in rendering time and rendering quality, with respect to other alternative methods. The method proposed also allows to add many interesting visual effects, even for object with large bumb maps, including non-s rendering, chrome effects, shading under multiple lights, rendering of different materials within a single object, specular reflections and others. Moreover, the implementation of the method is not complex and can be eased by software reuse.
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    Interpolatory ?3-Subdivision
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Labsik, U.; Greiner, G.
    We present a new interpolatory subdivision scheme for triangle meshes. Instead of splitting each edge and performing a 1-to-4 split for every triangle we compute a new vertex for every triangle and retriangulate the old and the new vertices. Using this refinement operator the number of triangles only triples in each step. New vertices are computed with a Butterfly like scheme. In order to obtain overall smooth surfaces special rules are necessary in the neighborhood of extraordinary vertices. The scheme is suitable for adaptive refinement by using an easy forward strategy. No temporary triangles are produced here which allows simpler data structures and makes the scheme easy to implement.
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    Subdivision Surface Tesselation on the Fly using a versatile Mesh Data Structure
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Muller, Kerstin; Havemann, Sven
    Subdivision surfaces have become a standard technique for freeform shape modeling. They are intuitive to use and permit designers to flexibly add detail. But with larger control meshes, efficient adaptive rendering techniques are indispensable for interactive visualization and shape modeling. In this paper, we present a realization of tesselation-on-the-fly for Loop subdivision surfaces as part of a framework for interactive visualization.
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    Augmented Reality with Back-Projection Systems using Transflective Surfaces
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Bimber, Oliver; Encarnacao, L. Miguel; Schmalstieg, Dieter
    In this paper, we introduce the concept of Extended VR (extending viewing space and interaction space of back-projection VR systems), by describing the use of a hand-held semi-transparent mirror to support augmented reality tasks with back-projection systems. This setup overcomes the problem of occlusion of virtual objects by real ones linked with such display systems. The presented approach allows an intuitive and effective application of immersive or semi-immersive virtual reality tasks and interaction techniques to an augmented surrounding space. Thereby, we use the tracked mirror as an interactive image-plane that merges the reflected graphics, which are displayed on the projection plane, with the transmitted image of the real environment. In our implementation, we also address traditional augmented reality problems, such as real-object registration and virtual-object occlusion. The presentation is complemented by a hypothesis of conceivable further setups that apply transflective surfaces to support an Extended VR environment.
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    External Memory View-Dependent Simplification
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) El-Sana, Jihad; Chiang, Yi-Jen
    In this paper, we propose a novel external-memory algorithm to support view-dependent simplification for datasets much larger than main memory. In the preprocessing phase, we use a new spanned sub-meshes simplification technique to build view-dependence trees I/O-efficiently, which preserves the correct edge collapsing order and thus assures the run-time image quality. We further process the resulting view-dependence trees to build the meta-node trees, which can facilitate the run-time level-of-detail rendering and is kept in disk. During run-time navigation, we keep in main memory only the portions of the meta-node trees that are necessary to render the current level of details, plus some prefetched portions that are likely to be needed in the near future. The prefetching prediction takes advantage of the nature of the run-time traversal of the meta-node trees, and is both simple and accurate. We also employ the implicit dependencies for preventing incorrect foldovers, as well as main-memory buffer management and parallel processes scheme to separate the disk accesses from the navigation operations, all in an integrated manner. The experiments show that our approach scales well with respect to the main memory size available, with encouraging preprocessing and run-time rendering speeds and without sacrificing the image quality.
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    Haptic Cues for Image Disambiguation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Faconti, G.; Massink, M.; Bordegoni, M.; De Angelis, F.; Booth, S.
    Haptic interfaces represent a revolution in human computer interface technology since they make it possible for users to touch and manipulate virtual objects. In this work we describe a cross-model interaction experiment to study the effect of adding haptic cues to visual cues when vision is not enough to disambiguate the images. We relate the results to those obtained in experimental psychology as well as to more recent studies on the subject.
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    Priority-Driven Acoustic Modeling for Virtual Environments
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Min, Patrick; Funkhouser, Thomas
    Geometric acoustic modeling systems spatialize sounds according to reverberation paths from a sound source to a receiver to give an auditory impression of a virtual 3D environment. These systems are useful for concert hall design, teleconferencing, training and simulation, and interactive virtual environments. In many cases, such as in an interactive walkthrough program, the reverberation paths must be updated within strict timing constraints - e.g., as the sound receiver moves under interactive control by a user. In this paper, we describe a geometric acoustic modeling algorithm that uses a priority queue to trace polyhedral beams representing reverberation paths in best-first order up to some termination criteria (e.g., expired time-slice). The advantage of this algorithm is that it is more likely to find the highest priority reverberation paths within a fixed time-slice, avoiding many geometric computations for lower-priority beams. Yet, there is overhead in computing priorities and managing the priority queue. The focus of this paper is to study the trade-offs of the priority-driven beam tracing algorithm with different priority functions. During experiments computing reverberation paths between a source and a receiver in a 3D building environment, we find that priority functions incorporating more accurate estimates of source-to-receiver path length are more likely to find early reverberation paths useful for spatialization, especially in situations where the source and receiver cannot reach each other through trivial reverberation paths. However, when receivers are added to the environment such that it becomes more densely and evenly populated, this advantage diminishes.
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    Robust Motion Watermarking based on Multiresolution Analysis
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Kim, Tae-hoon; Lee, Jehee; Shin, Sung yong
    Digital watermarking is one of commonly used solutions for copyright protection. A watermark should be imperceptible and robust to various attacks. In this paper, we address watermarking for motion data. Our watermarking scheme is based on two well-known ideas, so called multiresolution representation and spread spectrum. We embed a watermark into a motion signal by perturbing large detail coefficients of its multiresolution representation, and extract the watermark by analyzing perturbation of coefficients from a suspected signal. For more effective watermark extraction, we align suspected motion data to the original using dynamic time warping. Our scheme has merits of spread spectrum such as the resilience to common signal processing as well as the robustness to time warping.
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    Using an Intermediate Skeleton and Inverse Kinematics for Motion Retargeting
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Monzani, Jean-Sebastien; Baerlocher, Paolo; Boulic, Ronan; Thalmann, Daniel
    In this paper, we present a new method for solving the Motion Retargeting Problem, by using an intermediate skeleton. This allows us to convert movements between hierarchically and geometrically different characters. An Inverse Kinematics engine is then used to enforce Cartesian constraints while staying as close as possible to the captured motion.
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    Towards Blind Detection of Robust Watermarks in Polygonal Models
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Benedens, Oliver; Busch, Christoph
    We describe a Digital Watermarking system dedicated for embedding watermarks into 3D polygonal models. The system consists of three watermarking algorithms, one named Vertex Flood Algorithm (VFA) suitable for embedding fragile public readable watermarks with high capacity and offering a way of model authentication, one realizing affine invariant watermarks, named Affine Invariant Embedding (AIE) and a third one, named Normal Bin Encoding (NBE) algorithm, realizing watermarks with robustness against more complex operations, most noticeably polygon reduction. The watermarks generated by these algorithms are stackable. We shortly discuss the implementation of the system, which is realized as a 3D Studio MAX plugin.
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    Context-based Space Filling Curves
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Dafner, Revital; Cohen-Or, Daniel; Matias, Yossi
    A context-based scanning technique for images is presented. An image is scanned along a context-based space filling curve that is computed so as to exploit inherent coherence in the image. The resulting one-dimensional representation of the image has improved autocorrelation compared with universal scans such as the Peano-Hilbert space filling curve. An efficient algorithm for computing context-based space filling curves is presented. We also discuss the potential of improved autocorrelation of context-based space filling curves for image and video lossless compression.
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    The Impulse Graph: A New Dynamic Structure For Global Collisions
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Baciu, George; Keung Wong, Sai
    In interactive virtual environments and dynamic simulations, collisions between complex objects and articulated bodies may occur simultaneously at multiple points or regions of interference. Many solutions to the collision response problem are formulated based on the local pair-wise contact dynamics. In this article, we present a new solution to the global interactions and dynamic response between multiple structures in a three-dimensional environment. This is based on a new dynamic impulse graph that tracks the reaction forces through the entire system and gives a global view of all the interactions in a multibody system.
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    Realistic Collision Avoidance of Upper Limbs Based on Neuroscience Models
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Nebel, Jean-Christophe
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    Direct Manipulation and Interactive Sculpting of PDE Surfaces
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Du, Haixia; Qin, Hong
    This paper presents an integrated approach and a unified algorithm that combine the benefits of PDE surfaces and powerful physics-based modeling techniques within one single modeling framework, in order to realize the full potential of PDE surfaces. We have developed a novel system that allows direct manipulation and interactive sculpting of PDE surfaces at arbitrary location, hence supporting various interactive techniques beyond the conventional boundary control. Our prototype software affords users to interactively modify point, normal, curvature, and arbitrary region of PDE surfaces in a predictable way. We employ several simple, yet effective numerical techniques including the finite-difference discretization of the PDE surface, the multigrid-like subdivision on the PDE surface, the mass-spring approximation of the elastic PDE surface, etc. to achieve real-time performance. In addition, our dynamic PDE surfaces can also be approximated using standard bivariate B-spline finite elements, which can subsequently be sculpted and deformed directly in real-time subject to intrinsic PDE constraints. Our experiments demonstrate many attractive advantages of our dynamic PDE formulation such as intuitive control, real-time feedback, and usability to the general public.
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    Graceful Degradation of Collision Handling in Physically Based Animation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Dingliana, John; O'Sullivan, Carol
    Interactive simulation is made possible in many applications by simplifying or culling the finer details that would make real-time performance impossible. This paper examines detail simplification in the specific problem of collision handling for rigid body animation. We present an automated method for calculating consistent collision response at different levels of detail. The mechanism works closely with a system which uses a pre-computed hierarchical volume model for collision detection.
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    Multiresolution Shape Deformations for Meshes with Dynamic Vertex Connectivity
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Kobbelt, Leif P.; Bareuther, Thilo; Seidel, Hans-Peter
    Multiresolution shape representation is a very effective way to decompose surface geometry into several levels of detail. Geometric modeling with such representations enables flexible modifications of the global shape while preserving the detail information. Many schemes for modeling with multiresolution decompositions based on splines, polygonal meshes and subdivision surfaces have been proposed recently. In this paper we modify the classical concept of multiresolution representation by no longer requiring a global hierarchical structure that links the different levels of detail. Instead we represent the detail information implicitly by the geometric difference between independent meshes. The detail function is evaluated by shooting rays in normal direction from one surface to the other without assuming a consistent tesselation. In the context of multiresolution shape deformation, we propose a dynamic mesh representation which adapts the connectivity during the modification in order to maintain a prescribed mesh quality. Combining the two techniques leads to an efficient mechanism which enables extreme deformations of the global shape while preventing the mesh from degenerating. During the deformation, the detail is reconstructed in a natural and robust way. The key to the intuitive detail preservation is a transformation map which associates points on the original and the modified geometry with minimum distortion. We show several examples which demonstrate the effectiveness and robustness of our approach including the editing of multiresolution models and models with texture.
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    Color Distribution - A New Approach to Texture Compression
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Ivanov, Denis V.; Kuzmin, Yevgeniy P.
    Texture compression is recently one of the most important topics of 3D scene rendering techniques, because it allows rendering more complicated high-resolution scenes. However, because of some special requirements for these type of techniques, the commonly used block decomposition approach may introduce visual degradation of image details due to lack of colors. We present here a new approach to texture compression, which allows sharing of one color by several blocks providing a larger number of unique colors in each particular block and the best compression ratio. We also present an iterative algorithm for obtaining distributed colors on a texture, and discuss some advantages of our approach. The paper concludes with comparison of our technique with S3TC and other block decomposition methods.
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    A Multiresolution Model for Soft Objects Supporting Interactive Cuts and Lacerations
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Ganovelli, Fabio; Cignoni, Paolo; Montani, Claudio; Scopigno, Roberto
    Performing a really interactive and physically-based simulation of complex soft objects is still an open problem in computer animation/simulation. Given the application domain of virtual surgery training, a complete model should be quite realistic, interactive and should enable the user to modify the topology of the objects. Recent papers propose the adoption of multiresolution techniques to optimize time performance by representing at high resolution only the object parts considered more important or critical. The speed up obtainable at simulation time are counterbalanced by the need of a preprocessing phase strongly dependent on the topology of the object, with the drawback that performing dynamic topology modification becomes a prohibitive issue. In this paper we present an approach that couples multiresolution and topological modifications, based on the adoption of a particle systems approach to the physical simulation. Our approach is based on a tetrahedral decomposition of the space, chosen both for its suitability to support a particle system and for the ready availability of many techniques recently proposed for the simplification and multiresolution management of 3D simplicial decompositions. The multiresolution simulation system is designed to ensure the required speedup and to support dynamic changes of the topology, e.g. due to cuts or lacerations of the represented tissue.
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    Modeling the Motion of Dense Smoke in the Wind Field
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Rudolf, Marcin J.; Raczkowski, Jacek
    This paper presents a volumetric animation technique for modeling the turbulent motion of very dense and turbulent smoke such as one coming from a steam engine. A new method of the wind field generation is proposed. Gas motion is determined by the integration of two independent vector layers. The first one is a combination of flow primitives and the second is created by stochastically generated turbulence. Special attention is taken of the proper construction of the turbulent layer. For the visualization purposes a simple volume raytracer is applied. Many light sources are taken into account to achieve photorealistic effects. Finally some interesting animations are overviewed. Computation times for a PC Pentium 200 and an SGI O2 workstation are compared to demonstrate the high efficiency of the method.
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    An Adaptive Spectral Rendering with a Perceptual Control
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Claude Iehl, Jean; Peroche, Bernard
    In this paper, we present a spectral rendering method based on a ray tracing algorithm and guided by a perceptual control of the error made. An adaptive representation of spectral data for light sources and materials is used and induces, for each pixel, the evaluation of an algebraic expression. For each visible wavelength, the computations of complex spread in refractive and dispersive materials, based on several photon maps, are locally restricted by an adaptive evaluation of the expression. This method allows to simulate high quality physically-based pictures and, in particular, some specific phenomena like dispersion in transparent objects, scattered caustics,. . .
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    Tone Reproduction for Interactive Walkthroughs
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Scheel, A.; Stamminger, M.; Seidel, H.-P.
    When a rendering algorithm has created a pixel array of radiance values the task of producing an image is not yet completed. In fact, to visualize the result the radiance values still have to be mapped to luminances, which can be reproduced by the used display. This step is performed with the help of tone reproduction operators. These tools have mainly been applied to still images, but of course they are just as necessary for walkthrough applications, in which several images are created per second. In this paper we illuminate the physiological aspects of tone reproduction for interactive applications. It is shown how tone reproduction can also be introduced into interactive radiosity viewers, where the tone reproduction continuously adjusts to the current view of the user. The overall performance is decreased only moderately, still allowing walkthroughs of large scenes.
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    Integration of Multidimensional Interaction Devices in Real-Time Computer Graphics Applications
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Frohlich, Torsten; Roth, Marcus
    Modern CAD/CAM and Virtual Reality applications cannot be imagined without the new class of interaction devices allowing the user direct interaction with computer generated scenes. Integrating such devices into existing or newly developed software is a complex task for a number of reasons. The set of devices is very heterogeneous in functionality and data formats. Most devices are difficult to handle by inexperienced users or need careful handling and calibration. After reviewing a number of existing systems, a novel approach to this problem is presented. A device interface that allows the flexible, hardware independent configuration and error robust operation, even reconfiguration and exchanges of interaction devices during operation, will be introduced. The system structure is discussed and novel communication protocols reducing latency are invented.
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    Web-Based Remote Renderingwith IBRAC (Image-Based Rendering Acceleration and Compression)
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Yoon, I.; Neumann, U.
    Recent advances in Internet and computer graphics stimulate intensive use and development of 3D graphics on the World Wide Web. To increase efficiency of systems using 3D graphics on the web, the presented method utilizes previously rendered and transmitted images to accelerate the rendering and compression of new synthetic scene images. The algorithm employs ray casting and epipolar constraints to exploit spatial and temporal coherence between the current and previously rendered images. The reprojection of color and visibility data accelerates the computation of new images. The rendering method intrinsically computes a residual image, based on a user specified error tolerance that balances image quality against computation time and bandwidth. Encoding and decoding uses the same algorithm, so the transmitted residual image consists only of significant data without addresses or offsets. We measure rendering speed-ups of four to seven without visible degradation. Compression ratios per frame are a factor of two to ten better than MPEG2 in our test cases. There is no transmission of 3D scene data to delay the first image. The efficiency of the server and client generally increases with scene complexity or data size since the rendering time is predominantly a function of image size. This approach is attractive for remote rendering applications such as web-based scientific visualization where a client system may be a relatively low-performance machine and limited network bandwidth makes transmission of large 3D data impractical.
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    Interactive High-Quality Maximum Intensity Projection
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Mroz, Lukas; Hauser, Helwig; Groller, Eduard
    Maximum Intensity Projection (MIP) is a volume rendering technique which is used to visualize high-intensity structures within volumetric data. At each pixel the highest data value, which is encountered along a corresponding viewing ray is depicted. MIP is, for example, commonly used to extract vascular structures from medical data sets (angiography). Due to lack of depth information in MIP images, animation or interactive variation of viewing parameters is frequently used for investigation. Up to now no MIP algorithms exist which are of both interactive speed and high quality. In this paper we present a high-quality MIP algorithm (trilinear interpolation within cells), which is up to 50 times faster than brute-force MIP and at least 20 times faster than comparable optimized techniques. This speed-up is accomplished by using an alternative storage scheme for volume cells (sorted by value) and by removing cells which do not contribute to any MIP projection (regardless of the viewing direction) in a preprocessing step. Also, a fast maximum estimation within cells is used to further speed up the algorithm.
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    Fast Volume Rendering and Data Classification Using Multiresolution in Min-Max Octrees
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Dong, Feng; Krokos, Meleagros; Clapworthy, Gordon
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    Gradient Estimation in Volume Data using 4D Linear Regression
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Neumann, Laszlo; Csebfalvi, Balazs; Konig, Andreas; Groller, Eduard
    In this paper a new gradient estimation method is presented which is based on linear regression. Previous contextual shading techniques try to fit an approximate function to a set of surface points in the neighborhood of a given voxel. Therefore a system of linear equations has to be solved using the computationally expensive Gaussian elimination. In contrast, our method approximates the density function itself in a local neighborhood with a 3D regression hyperplane. This approach also leads to a system of linear equations but we will show that it can be solved with an efficient convolution. Our method provides at each voxel location the normal vector and the translation of the regression hyperplane which are considered as a gradient and a filtered density value respectively. Therefore this technique can be used for surface smoothing and gradient estimation at the same time.
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    Virtual Dunhuang Mural Restoration System in Collaborative Network Environment
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Li, Xiangyang; Lu, Dongming; Pan, Yunhe
    This paper introduces a virtual Dunhuang mural restoration system in collaborative network environment. It describes the style of Dunhuang mural, analyzes the reasons of mural spoilage, and presents the necessity to develop a collaborative mural restoration GroupWare. It describes the components and the workflow of mural restoration in detail, solves some key technologies in the system. In the end, it introduces the system architecture, and presents the system interface and some restored results.
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    Collaborative Virtual Simulation Environment for Radiotherapy Treatment Planning
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Cai, Wenli; Walter, Stefan; Karangelis, Grigorios; Sakas, Georgios
    The simulation of Radiotherapy Treatment Planning (RTP) is a normal procedure in oncology clinics carried out on a Simulator machine. The Virtual Simulation of RTP replaces the real Simulator machine with a virtual one by using the CT data sets of a patient instead of the real patient. In this paper, we present a collaborative virtual simulation environment of RTP, named EU-VIRTUOSO, which is based on volume rendering and telecommunication techniques. The RTP procedure is visualised on a virtual patient, which is created by using the CT data of the patient. Different volume rendering and volume interaction techniques, such as DRR, MIP, gradient surface, and iso-surface, supply physicians with high quality rendering images to simulate the real working environment of the Simulator machine. In the collaborative environment, physicians distributed at different locations can work together via network to plan the treatment or to validate the treatment plan on-line by a collaborative application sharing approach. Both concepts virtualised planning and collaborative planning improve the efficiency and accuracy of a radiotherapy treatment while reducing the effort for an individual patient.
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    Reshaping the Coliseum in Rome: An Integrated Data Capture and Modeling Method at Heritage Sites
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Gaiani, Marco; Balzani, Marcello; Uccelli, Federico
    The paper describes the process of building Internet-transmittable, 3-D digital virtual models of ancient heritage monuments from on-site data, focusing especially on 3-D dimensional data acquisition techniques and color processing methods. Section 1 considers project goals and the attendant problems; Section 2 provides a brief summary of state-of-the-art experience and the technologies adopted by the Authors; Section 3 illustrates the key features of the 3-D color data acquisition methods used as well as the shape and color processing pipeline; Section 4 describes the specific study conducted on single elements and faades of the Coliseum in Rome, while Section 6 outlines future work.
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    Unsteady Flow Visualization by Animating Evenly-Spaced Streamlines
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Jobard, Bruno; Lefer, Wilfrid
    In recent years the work on vector field visualization has been concentrated on LIC-based methods. In this paper we propose an alternative solution for the visualization of unsteady flow fields. Our approach is based on the computation of temporal series of correlated images. While other methods are based on pathlines and try to correlate successive images at the pixel level, our approach consists in correlating instantaneous visualizations of the vector field at the streamline level. For each frame a feed forward algorithm computes a set of evenly-spaced streamlines as a function of the streamlines generated for the previous frame. This is achieved by establishing a correspondence between streamlines at successive time steps. A cyclical texture is mapped onto every streamline and textures of corresponding streamlines at different time steps are correlated together so that, during the animation, they move along the streamlines, giving the illusion that the flow is moving in the direction defined by the streamline. Our method gives full control on the image density so that we are able to produce smooth animations of arbitrary density, covering the field of representations from sparse, that is classical streamline-based images, to dense, that is texture-like images.
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    A Video-Based 3D-Reconstruction of Soccer Games
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Bebie, T.; Bieri, H.
    In this paper we present SoccerMan, a reconstruction system designed to generate animated, virtual 3D views from two synchronous video sequences of a short part of a given soccer game. After the reconstruction process, which needs also some manual interaction, the virtual 3D scene can be examined and 'replayed' from any viewpoint. Players are modeled as so-called animated texture objects, i.e. 2D player shapes are extracted from video and texture-mapped onto rectangles in 3D space. Animated texture objects have shown very appropriate as a 3D representation of soccer players in motion, as the visual nature of the original human motion is preserved. The trajectories of the players and the ball in 3D space are reconstructed accurately. In order to create a 3D reconstruction of a given soccer scene, the following steps have to be executed: 1) Camera parameters of all frames of both sequences are computed (camera calibration). 2) The playground texture is extracted from the video sequences. 3) Trajectories of the ball and the players' heads are computed after manually specifying their image positions in a few key frames. 4) Player textures are extracted automatically from video. 5) The shapes of colliding or occluding players are separated automatically. 6) For visualization, player shapes are texture-mapped onto appropriately placed rectangles in virtual space. SoccerMan is a novel experimental sports analysis system with fairly ambitious objectives. Its design decisions, in particular to start from two synchronous video sequences and to model players by texture objects, have already proven promising.
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    Video-based Approach to Human Animation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Lao, Zhiqiang; Li, Ling
    A method based on computer vision technologies is presented to determine the 3-D spatial locations of joints or feature points of a human body from human motion video. The proposed method first applies the geometric projection theory to obtain a set of feasible postures in some key frames according to predefined 2D video features and 3D-model features correspondence. Next it makes use of the available skeleton controlled human model to get a feasible posture for each key frame. The method is applied to a series of video images to animate artificial 3D human models.
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    Representing Animations by Principal Components
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Alexa, Marc; Muller, Wolfgang
    In this paper, we present a representation for three-dimensional geometric animation sequences. Different from standard key-frame techniques, this approach is based on the determination of principal animation components and decouples the animation from the underlying geometry. The new representation supports progressive animation compression with spatial, as well as temporal, level-of-detail and high compression ratios. The distinction of animation and geometry allows for mapping animations onto other objects.
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    A Vector-based Representation for Image Warping
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Froumentin, Max; Labrosse, Frederic; Willis, Philip
    A method for image analysis, representation and re-synthesis is introduced. Unlike other schemes it is not pixel based but rather represents a picture as vector data, from which an altered version of the original image can be rendered. Representing an image as vector data allows performing operations such as zooming, retouching or colourising, avoiding common problems associated with pixel image manipulation. This paper brings together methods from the areas of computer vision, image compositing and image based rendering to prove that this type of image representation is a step towards accurate and efficient image manipulation.
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    Real Time Local Approximation of Deformations using Rotations
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Maillot, Jerome
    Additional realism can be achieved in computer generated images using smooth and increasingly complex deformations. Though significant effort has been spent on improving these deformations, no general method has been proposed yet to deal with rigid pieces connected to soft objects. This paper proposes a general framework to solve this problem. We will present several types of applications, such as flowing small objects in a deformation field, animating rigid features connected to some deformed object, or smoothly attached limbs to a deforming body. All the calculations presented here can be applied to any type of deformation, provided that the deformation at each point only depends on the point itself. Even though we can directly compute the result for some analytical deformation fields, we will show that a good sampling of the deformation in the area of interest is generally enough. One intermediate result consists of a practical method to find the best rotation that approximates a linear transformation. The proposed method is a superset of the Gram-Schmidt orthonormalization process, and is much easier to compute than global methods based on Taylor series.
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    Motion Balance Filtering
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Tak, Seyoon; Song, Oh-young; Ko, Hyeong-Seok
    This paper presents a new technique called motion balance filtering, which corrects an unbalanced motion to a balanced one while preserving the original motion characteristics as much as possible. Differently from previous approaches that deal only with the balance of static posture, we solve the problem of balancing a dynamic motion. We achieve dynamic balance by analyzing and controlling the trajectory of the zero moment point (ZMP). Our algorithm consists of three steps. First, it analyzes the ZMP trajectory to find out the duration in which dynamic balance is violated. Dynamic imbalance is identified by the ZMP trajectory segments lying out of the supporting area. Next, the algorithm modifies the ZMP trajectory by projecting it into the supporting area. Finally, it generates the balanced motion that satisfies the new ZMP constraint. This process is formulated as a constrained optimization problem so that the new motion resembles the original motion as much as possible. Experiments prove that our motion balance filtering algorithm is a useful method to add physical realism to a kinematically edited motion.
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    Generating Consistent Motion Transition via Decoupled Framespace Interpolation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Ashraf, G.; Wong, K. C.
    The framespace interpolation algorithm abstracts motion sequences as 1D signals, and interpolates between them to create higher dimension signals, with weights drawn from a user specified curve in a bounded region. We reformulate the algorithm to achieve motion-state based transition via dynamic warping of framespaces and automatic transition timing via framespace frequency interpolation. Basis motions displaying diverse coordination configurations between upper and lower body-halves, cannot be consistently corresponded at a macro level. We address this problem here, through decoupled blending of these halves to achieve true consistency, and eliminate accumulated phase differences via cosine phase warp functions. This generalization enables interpolation of motions with diverse coordinations between the upper and lower bodies.
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    Floating Points: A Method for Computing Stipple Drawings
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Deussen, Oliver; Hiller, Stefan; Van Overveld, Cornelius; Strothotte, Thomas
    We present a method for computer generated pen-and-ink illustrations by the simulation of stippling. In a stipple drawing, dots are used to represent tone and also material of surfaces. We create such drawings by generating an initial dot set which is then processed by a relaxation method based on Voronoi diagrams. The point patterns generated are approximations of Poisson disc distributions and can also be used for integrating functions or the positioning of objects. We provide an editor similar to paint systems for interactively creating stipple drawings. This makes it possible to create such drawings within a matter of hours, instead of days or even weeks when the drawing is done manually.
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    Surface Reconstruction based on Lower Dimensional Localized Delaunay Triangulation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Gopi, M.; Krishnan, S.; Silva, C.T.
    We present a fast, memory efficient algorithm that generates a manifold triangular mesh S passing through a set of unorganized points P R 3. Nothing is assumed about the geometry, topology or presence of boundaries in the data set except that P is sampled from a real manifold surface. The speed of our algorithm is derived from a projection-based approach we use to determine the incident faces on a point. We define our sampling criteria to sample the surface and guarantee a topologically correct mesh after surface reconstruction for such a sampled surface. We also present a new algorithm to find the normal at a vertex, when the surface is sampled according our given criteria. We also present results of our surface reconstruction using our algorithm on unorganized point clouds of various models.
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    An Interactive Approach to Point Cloud Triangulation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Kobbelt, Leif P.; Botsch, Mario
    We present an interactive system for the generation of high quality triangle meshes that allows us to handle hybrid geometry (point clouds, polygons,. . .) as input data. In order to be able to robustly process huge data sets, we exploit graphics hardware features like the raster manager and the z-buffer for specific sub-tasks in the overall procedure. By this we significantly accelerate the stitching of mesh patches and obtain an algorithm for sub-sampling the data points in linear time. The target resolution and the triangle alignment in sub-regions of the resulting mesh can be controlled by adjusting the screen resolution and viewing transformation. An intuitive user interface provides a flexible tool for application dependent optimization of the mesh.
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    Automatic Surface Reconstruction from Point Sets in Space
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Attene, Marco; Spagnuolo, Michela
    In this paper an algorithm is proposed that takes as input a generic set of unorganized points, sampled on a real object, and returns a closed interpolating surface. Specifically, this method generates a closed 2-manifold surface made of triangular faces, without limitations on the shape or genus of the original solid. The reconstruction method is based on generation of the Delaunay tetrahedralization of the point set, followed by a sculpturing process constrained to particular criteria. The main applications of this tool are in medical analysis and in reverse engineering areas. It is possible, for example, to reconstruct anatomical parts starting from surveys based on TACs or magnetic resonance.
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    Integrating Occlusion Culling and Levels of Detail through Hardly-Visible Sets
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Andujar, Carlos; Saona-Vazquez, Carlos; Navazo, Isabel; Brunet, Pere
    Occlusion culling and level-of-detail rendering have become two powerful tools for accelerating the handling of very large models in real-time visualization applications. We present a framework that combines both techniques to improve rendering times. Classical occlusion culling algorithms compute potentially visible sets (PVS), which are supersets of the sets of visible polygons. The novelty of our approach is to estimate the degree of visibility of each object of the PVS using synthesized coarse occluders. This allows to arrange the objects of each PVS into several Hardly-Visible Sets (HVS) with similar occlusion degree. According to image accuracy and frame rate requirements, HVS provide a way to avoid sending to the graphics pipeline those objects whose pixel contribution is low due to partial occlusion. The image error can be bounded by the user at navigation time. On the other hand, as HVS offer a tighter estimation of the pixel contribution for each scene object, it can be used for a more convenient selection of the level-of-detail at which objects are rendered. In this paper, we describe the new framework technique, provide details of its implementation using a visibility octree as the chosen occlusion culling data structure and show some experimental results on the image quality.
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    Directional Discretized Occluders for Accelerated Occlusion Culling
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Bernardini, Fausto; Klosowski, James T.; El-Sana, Jihad
    We present a technique for accelerating the rendering of high depth-complexity scenes. In a preprocessing stage, we approximate the input model with a hierarchical data structure and compute simple view-dependent polygonal occluders to replace the complex input geometry in subsequent visibility queries. When the user is inspecting and visualizing the input model, the computed occluders are used to avoid rendering geometry which cannot be seen. Our method has several advantages which allow it to perform conservative visibility queries efficiently and it does not require any special graphics hardware. The preprocessing step of our approach can also be used within the framework of other visibility culling methods which need to pre-select or pre-render occluders. In this paper, we describe our technique and its implementation in detail, and provide experimental evidence of its performance. In addition, we briefly discuss possible extensions of our algorithm.
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    Colour Section
    (Blackwell Publishers Ltd and the Eurographics Association, 2000)
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    Efficient Algorithms for Computing Conservative Portal Visibility Information
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Jimenez, W. F. H.; Esperanca, C.; Oliveira, A. A. F.
    The number of polygons in realistic architectural models is many more than can be rendered at interactive frame rates. Typically, however, due to occlusion by opaque surfaces (e.g., walls), only small fractions of such models are visible from most viewpoints. This fact is used in many popular methods for preprocessing visibility information which assume a scene model subdivided into convex cells connected through convex portals. These methods need to establish which cells or parts thereof are visible to a generalized observer located within each cell. The geometry of this information is termed a 'visibility volume' and its computation is usually quite complex. Conservative approximations of viewing volumes, however, are simpler and less expensive to compute. In this paper we present techniques and algorithms which permit the computation of conservative viewing volumes incrementally. In particular, we describe an algorithm for computing the viewing volumes for a given cell through a sequence of 'm' portals containing a total of 'n' edges in Omn time.
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    LCTS: Ray Shooting using Longest Common Traversal Sequences
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Havran, V.; Bittner, J.
    We describe two new techniques of ray shooting acceleration that exploit the traversal coherence of a spatial hierarchy. The first technique determines a sequence of adjacent leaf-cells of the hierarchy that is pierced by all rays contained within a certain convex shaft. This sequence is used to accelerate ray shooting for all remaining rays within the shaft. The second technique establishes a cut of the hierarchy that contains nodes where the hierarchy traversal can no longer be predetermined for all rays contained within a given shaft. This cut is used to initiate the traversal for all remaining rays contained in the shaft. The description of the methods is followed by results evaluated by their practical implementation.
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    Automatic Generation of Virtual Woodblocks and Multicolor Woodblock Printing
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Mizuno, S.; Kasaura, T.; Okouchi, T.; Yamamoto, S.; Okada, M.; Toriwaki, J.
    In this paper, we study a method to synthesize a multicolor virtual woodblock print by using several virtual woodblocks. It consists of two sections: carving and printing, to synthesize a virtual print. In the carving section, virtual woodblocks are generated by a user with supporting of an automatically carving method based on feature extraction of a gray value image. And woodblocks are also generated automatically by using a full-color image as a draft. In the printing section, a "paper sheet", a "printing brush" and "ink" are prepared in addition to the "woodblock" in the virtual space and the user synthesizes a woodblock print interactively. As the printing factors, a color of ink, a moisture value and a grain change the finish of the print. Using several virtual woodblocks and printing to a paper sheet in succession, a printing image of each woodblock is combined based on the printing factors and a multicolor virtual prints is synthesized.
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    Modelling virtual cities dedicated to behavioural animation
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Thomas, Gwenola; Donikian, Stephane
    In order to populate virtual cities, it is necessary to specify the behaviour of dynamic entities such as pedestrians or car drivers. Since a complete mental model based on vision and image processing cannot be constructed in real time using purely geometrical information, higher levels of information are needed in a model of the virtual environment. For example, the autonomous actors of a virtual world would exploit the knowledge of the environment topology to navigate through it. In this article, we present a model of virtual urban environments using structures and information suitable for behavioural animations. Thanks to this knowledge, autonomous virtual actors can behave like pedestrians or car drivers in a complex city environment. A city modeler has been designed, using this model of urban environment, and enables complex urban environments for behavioural animation to be automatically produced.
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    Binding Virtual Environments to Toolkit Capabilities
    (Blackwell Publishers Ltd and the Eurographics Association, 2000) Smith, Shamus P.; Duke, David J.
    There are many toolkits and development environments that aid the process of constructing virtual environment applications. Many of these development environments encourage customising a virtual environment's design while rapid prototyping within the confines of a toolkit's capabilities. Thus the choice of the technology and its associated support has been made independent of the end-use requirements of the final system. This can bias a virtual environment's design by implementation based constraints. We propose that an alternative approach is the consideration of virtual environment requirements in the context of an inspectable design model, to identify the requirements that a toolkit will need to support. In the context of an example, we present a selection of design requirements that we consider important for virtual environment design in general. We explore how these requirements might be mapped to different capabilities using Virtual Reality Modelling Language (VRML) as a concrete example of a platform technology.