27-Issue 2

Permanent URI for this collection

https://diglib7.eg.org/handle/10.2312/135
EG Proceedings

BibTeX (27-Issue 2)
                
@article{
10.1111:j.1467-8659.2008.01170.x,

journal = {Computer Graphics Forum},
title = {{
Frontmatter}},

author = {},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01170.x}

}
                
@article{
10.1111:j.1467-8659.2008.01114.x,

journal = {Computer Graphics Forum},
title = {{
Reduced Depth and Visual Hulls of Complex 3D Scenes}},

author = {
Bogomjakov, Alexander
 and 
Gotsman, Craig
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01114.x}

}
                
@article{
10.1111:j.1467-8659.2008.01112.x,

journal = {Computer Graphics Forum},
title = {{
Surface Reconstruction From Non-parallel Curve Networks}},

author = {
Liu, L.
 and 
Bajaj, C.
 and 
Deasy, J. O.
 and 
Low, D. A.
 and 
Ju, T.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01112.x}

}
                
@article{
10.1111:j.1467-8659.2008.01113.x,

journal = {Computer Graphics Forum},
title = {{
High-Resolution Volumetric Computation of Offset Surfaces with Feature Preservation}},

author = {
Pavic, Darko
 and 
Kobbelt, Leif
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01113.x}

}
                
@article{
10.1111:j.1467-8659.2008.01115.x,

journal = {Computer Graphics Forum},
title = {{
Render2MPEG: A Perception-based Framework Towards Integrating Rendering and Video Compression}},

author = {
Herzog, Robert
 and 
Kinuwaki, Shinichi
 and 
Myszkowski, Karol
 and 
Seidel, Hans-Peter
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01115.x}

}
                
@article{
10.1111:j.1467-8659.2008.01117.x,

journal = {Computer Graphics Forum},
title = {{
Effect of Character Animacy and Preparatory Motion on Perceptual Magnitude of Errors in Ballistic Motion}},

author = {
Reitsma, P. S. A.
 and 
Andrews, J.
 and 
Pollard, N. S.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01117.x}

}
                
@article{
10.1111:j.1467-8659.2008.01116.x,

journal = {Computer Graphics Forum},
title = {{
Apparent Greyscale: A Simple and Fast Conversion to Perceptually Accurate Images and Video}},

author = {
Smith, Kaleigh
 and 
Landes, Pierre-Edouard
 and 
Thollot, Joelle
 and 
Myszkowski, Karol
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01116.x}

}
                
@article{
10.1111:j.1467-8659.2008.01118.x,

journal = {Computer Graphics Forum},
title = {{
Lighting and Occlusion in a Wave-Based Framework}},

author = {
Ziegler, Remo
 and 
Croci, Simone
 and 
Gross, Markus
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01118.x}

}
                
@article{
10.1111:j.1467-8659.2008.01119.x,

journal = {Computer Graphics Forum},
title = {{
CHC++: Coherent Hierarchical Culling Revisited}},

author = {
Mattausch, Oliver
 and 
Bittner, Jiri
 and 
Wimmer, Michael
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01119.x}

}
                
@article{
10.1111:j.1467-8659.2008.01120.x,

journal = {Computer Graphics Forum},
title = {{
GPU Accelerated Direct Volume Rendering on an Interactive Light Field Display}},

author = {
Agus, Marco
 and 
Gobbetti, Enrico
 and 
Guitian, Jose Antonio Iglesias
 and 
Marton, Fabio
 and 
Pintore, Giovanni
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01120.x}

}
                
@article{
10.1111:j.1467-8659.2008.01121.x,

journal = {Computer Graphics Forum},
title = {{
Curvature-Domain Shape Processing}},

author = {
Eigensatz, Michael
 and 
Sumner, Robert W.
 and 
Pauly, Mark
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01121.x}

}
                
@article{
10.1111:j.1467-8659.2008.01122.x,

journal = {Computer Graphics Forum},
title = {{
Spectral Geometry Processing with Manifold Harmonics}},

author = {
Vallet, B.
 and 
Levy, B.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01122.x}

}
                
@article{
10.1111:j.1467-8659.2008.01123.x,

journal = {Computer Graphics Forum},
title = {{
Fast Force Field Approximation and its Application to Skeletonization of Discrete 3D Objects}},

author = {
Brunner, D.
 and 
Brunnett, G.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01123.x}

}
                
@article{
10.1111:j.1467-8659.2008.01124.x,

journal = {Computer Graphics Forum},
title = {{
Video Relighting Using Infrared Illumination}},

author = {
Wang, Oliver
 and 
Davis, James
 and 
Chuang, Erika
 and 
Rickard, Ian
 and 
De Mesa, Krystle
 and 
Dave, Chirag
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01124.x}

}
                
@article{
10.1111:j.1467-8659.2008.01126.x,

journal = {Computer Graphics Forum},
title = {{
Stereo Light Probe}},

author = {
Corsini, Massimiliano
 and 
Callieri, Marco
 and 
Cignoni, Paolo
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01126.x}

}
                
@article{
10.1111:j.1467-8659.2008.01125.x,

journal = {Computer Graphics Forum},
title = {{
Augmented Panoramic Video}},

author = {
Hermans, C.
 and 
Vanaken, C.
 and 
Mertens, T.
 and 
Van Reeth, F.
 and 
Bekaert, P.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01125.x}

}
                
@article{
10.1111:j.1467-8659.2008.01127.x,

journal = {Computer Graphics Forum},
title = {{
Sketching and Composing Widgets for 3D Manipulation}},

author = {
Schmidt, Ryan
 and 
Singh, Karan
 and 
Balakrishnan, Ravin
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01127.x}

}
                
@article{
10.1111:j.1467-8659.2008.01128.x,

journal = {Computer Graphics Forum},
title = {{
Real-Time Rendering and Editing of Vector-based Terrains}},

author = {
Bruneton, Eric
 and 
Neyret, Fabrice
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01128.x}

}
                
@article{
10.1111:j.1467-8659.2008.01129.x,

journal = {Computer Graphics Forum},
title = {{
Sketch-Based Procedural Surface Modeling and Compositing Using Surface Trees}},

author = {
Schmidt, Ryan
 and 
Singh, Karan
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01129.x}

}
                
@article{
10.1111:j.1467-8659.2008.01130.x,

journal = {Computer Graphics Forum},
title = {{
Hardware-Accelerated, High-Quality Rendering Based on Trivariate Splines Approximating Volume Data}},

author = {
Kalbe, Thomas
 and 
Zeilfelder, Frank
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01130.x}

}
                
@article{
10.1111:j.1467-8659.2008.01131.x,

journal = {Computer Graphics Forum},
title = {{
Zippy: A Framework for Computation and Visualization on a GPU Cluster}},

author = {
Fan, Zhe
 and 
Qiu, Feng
 and 
Kaufman, Arie E.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01131.x}

}
                
@article{
10.1111:j.1467-8659.2008.01132.x,

journal = {Computer Graphics Forum},
title = {{
GPU-based Fast Ray Casting for a Large Number of Metaballs}},

author = {
Kanamori, Yoshihiro
 and 
Szego, Zoltan
 and 
Nishita, Tomoyuki
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01132.x}

}
                
@article{
10.1111:j.1467-8659.2008.01134.x,

journal = {Computer Graphics Forum},
title = {{
Simulation of Human Motion Data using Short-Horizon Model-Predictive Control}},

author = {
Da Silva, M.
 and 
Abe, Y.
 and 
Popovic, J.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01134.x}

}
                
@article{
10.1111:j.1467-8659.2008.01133.x,

journal = {Computer Graphics Forum},
title = {{
Ray Casting Algebraic Surfaces using the Frustum Form}},

author = {
Reimers, Martin
 and 
Seland, Johan
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01133.x}

}
                
@article{
10.1111:j.1467-8659.2008.01135.x,

journal = {Computer Graphics Forum},
title = {{
Expressive Facial Gestures From Motion Capture Data}},

author = {
Ju, Eunjung
 and 
Lee, Jehee
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01135.x}

}
                
@article{
10.1111:j.1467-8659.2008.01136.x,

journal = {Computer Graphics Forum},
title = {{
Automatic Conversion of Mesh Animations into Skeleton-based Animations}},

author = {
De Aguiar, Edilson
 and 
Theobalt, Christian
 and 
Thrun, Sebastian
 and 
Seidel, Hans-Peter
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01136.x}

}
                
@article{
10.1111:j.1467-8659.2008.01137.x,

journal = {Computer Graphics Forum},
title = {{
Articulated Object Reconstruction and Markerless Motion Capture from Depth Video}},

author = {
Pekelny, Yuri
 and 
Gotsman, Craig
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01137.x}

}
                
@article{
10.1111:j.1467-8659.2008.01138.x,

journal = {Computer Graphics Forum},
title = {{
Floating Textures}},

author = {
Eisemann, M.
 and 
De Decker, B.
 and 
Magnor, M.
 and 
Bekaert, P.
 and 
De Aguiar, E.
 and 
Ahmed, N.
 and 
Theobalt, C.
 and 
Sellent, A.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01138.x}

}
                
@article{
10.1111:j.1467-8659.2008.01139.x,

journal = {Computer Graphics Forum},
title = {{
Texture Synthesis From Photographs}},

author = {
Eisenacher, C.
 and 
Lefebvre, S.
 and 
Stamminger, M.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01139.x}

}
                
@article{
10.1111:j.1467-8659.2008.01140.x,

journal = {Computer Graphics Forum},
title = {{
An Example-based Procedural System for Element Arrangement}},

author = {
Ijiri, Takashi
 and 
Mech, Radomir
 and 
Igarashi, Takeo
 and 
Miller, Gavin
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01140.x}

}
                
@article{
10.1111:j.1467-8659.2008.01141.x,

journal = {Computer Graphics Forum},
title = {{
Manifold-valued Thin-Plate Splines with Applications in Computer Graphics}},

author = {
Steinke, Florian
 and 
Hein, Matthias
 and 
Peters, Jan
 and 
Schoelkopf, Bernhard
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01141.x}

}
                
@article{
10.1111:j.1467-8659.2008.01142.x,

journal = {Computer Graphics Forum},
title = {{
Conformal Flattening by Curvature Prescription and Metric Scaling}},

author = {
Ben-Chen, Mirela
 and 
Gotsman, Craig
 and 
Bunin, Guy
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01142.x}

}
                
@article{
10.1111:j.1467-8659.2008.01143.x,

journal = {Computer Graphics Forum},
title = {{
Higher Order Barycentric Coordinates}},

author = {
Langer, Torsten
 and 
Seidel, Hans-Peter
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01143.x}

}
                
@article{
10.1111:j.1467-8659.2008.01144.x,

journal = {Computer Graphics Forum},
title = {{
A Semi-Lagrangian CIP Fluid Solver without Dimensional Splitting}},

author = {
Kim, Doyub
 and 
Song, Oh-young
 and 
Ko, Hyeong-Seok
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01144.x}

}
                
@article{
10.1111:j.1467-8659.2008.01146.x,

journal = {Computer Graphics Forum},
title = {{
Fluid in Video: Augmenting Real Video with Simulated Fluids}},

author = {
Kwatra, Vivek
 and 
Mordohai, Philippos
 and 
Narain, Rahul
 and 
Penta, Sashi Kumar
 and 
Carlsonk, Mark
 and 
Pollefeys, Marc
 and 
Lin, Ming C.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01146.x}

}
                
@article{
10.1111:j.1467-8659.2008.01145.x,

journal = {Computer Graphics Forum},
title = {{
A Fast Simulation Method Using Overlapping Grids for Interactions between Smoke and Rigid Objects}},

author = {
Dobashi, Yoshinori
 and 
Matsuda, Yasuhiro
 and 
Yamamoto, Tsuyoshi
 and 
Nishita, Tomoyuki
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01145.x}

}
                
@article{
10.1111:j.1467-8659.2008.01147.x,

journal = {Computer Graphics Forum},
title = {{
An Adaptive Contact Model for the Robust Simulation of Knots}},

author = {
Spillmann, Jonas
 and 
Teschner, Matthias
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01147.x}

}
                
@article{
10.1111:j.1467-8659.2008.01148.x,

journal = {Computer Graphics Forum},
title = {{
Single-pass Scalable Subsurface Rendering with Lightcuts}},

author = {
Arbree, Adam
 and 
Walter, Bruce
 and 
Bala, Kavita
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01148.x}

}
                
@article{
10.1111:j.1467-8659.2008.01149.x,

journal = {Computer Graphics Forum},
title = {{
Real-Time Translucent Rendering Using GPU-based Texture Space Importance Sampling}},

author = {
Chang, Chih-Wen
 and 
Lin, Wen-Chieh
 and 
Ho, Tan-Chi
 and 
Huang, Tsung-Shian
 and 
Chuang, Jung-Hong
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01149.x}

}
                
@article{
10.1111:j.1467-8659.2008.01150.x,

journal = {Computer Graphics Forum},
title = {{
Photo-realistic Rendering of Metallic Car Paint from Image-Based Measurements}},

author = {
Rump, Martin
 and 
Mueller, Gero
 and 
Sarlette, Ralf
 and 
Koch, Dirk
 and 
Klein, Reinhard
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01150.x}

}
                
@article{
10.1111:j.1467-8659.2008.01151.x,

journal = {Computer Graphics Forum},
title = {{
Efficient and Dynamic Simplification of Line Drawings}},

author = {
Shesh, Amit
 and 
Chen, Baoquan
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01151.x}

}
                
@article{
10.1111:j.1467-8659.2008.01152.x,

journal = {Computer Graphics Forum},
title = {{
Visualizing Underwater Ocean Optics}},

author = {
Gutierrez, Diego
 and 
Seron, Francisco J.
 and 
Munoz, Adolfo
 and 
Anson, Oscar
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01152.x}

}
                
@article{
10.1111:j.1467-8659.2008.01153.x,

journal = {Computer Graphics Forum},
title = {{
The Beam Radiance Estimate for Volumetric Photon Mapping}},

author = {
Jarosz, Wojciech
 and 
Zwicker, Matthias
 and 
Jensen, Henrik Wann
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01153.x}

}
                
@article{
10.1111:j.1467-8659.2008.01155.x,

journal = {Computer Graphics Forum},
title = {{
The Shadow Meets the Mask: Pyramid-Based Shadow Removal}},

author = {
Shor, Yael
 and 
Lischinski, Dani
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01155.x}

}
                
@article{
10.1111:j.1467-8659.2008.01154.x,

journal = {Computer Graphics Forum},
title = {{
Interactive Volume Rendering with Dynamic Ambient Occlusion and Color Bleeding}},

author = {
Ropinski, Timo
 and 
Meyer-Spradow, Jennis
 and 
Diepenbrock, Stefan
 and 
Mensmann, Joerg
 and 
Hinrichs, Klaus
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01154.x}

}
                
@article{
10.1111:j.1467-8659.2008.01156.x,

journal = {Computer Graphics Forum},
title = {{
Detail-In-Context Visualization for Satellite Imagery}},

author = {
Boettger, Joachim
 and 
Preiser, Martin
 and 
Balzer, Michael
 and 
Deussen, Oliver
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01156.x}

}
                
@article{
10.1111:j.1467-8659.2008.01157.x,

journal = {Computer Graphics Forum},
title = {{
Viewfinder Alignment}},

author = {
Adams, Andrew
 and 
Gelfand, Natasha
 and 
Pulli, Kari
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01157.x}

}
                
@article{
10.1111:j.1467-8659.2008.01158.x,

journal = {Computer Graphics Forum},
title = {{
Image-based Aging Using Evolutionary Computing}},

author = {
Hubball, Daniel
 and 
Chen, Min
 and 
Grant, Phil W.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01158.x}

}
                
@article{
10.1111:j.1467-8659.2008.01159.x,

journal = {Computer Graphics Forum},
title = {{
Image-based Material Weathering}},

author = {
Xuey, Su
 and 
Wang, Jiaping
 and 
Tong, Xin
 and 
Dai, Qionghai
 and 
Guo, Baining
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01159.x}

}
                
@article{
10.1111:j.1467-8659.2008.01163.x,

journal = {Computer Graphics Forum},
title = {{
Dynamic Sampling and Rendering of Algebraic Point Set Surfaces}},

author = {
Guennebaud, Gael
 and 
Germann, Marcel
 and 
Gross, Markus
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01163.x}

}
                
@article{
10.1111:j.1467-8659.2008.01161.x,

journal = {Computer Graphics Forum},
title = {{
Distortion-Free Steganography for Polygonal Meshes}},

author = {
Bogomjakov, Alexander
 and 
Gotsman, Craig
 and 
Isenburg, Martin
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01161.x}

}
                
@article{
10.1111:j.1467-8659.2008.01160.x,

journal = {Computer Graphics Forum},
title = {{
Image-based Shaving}},

author = {
Nguyen, Minh Hoai
 and 
Lalonde, Jean-Francois
 and 
Efros, Alexei A.
 and 
De la Torre, Fernando
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01160.x}

}
                
@article{
10.1111:j.1467-8659.2008.01162.x,

journal = {Computer Graphics Forum},
title = {{
Sparse points matching by combining 3D mesh saliency with statistical descriptors}},

author = {
Castellani, U.
 and 
Cristani, M.
 and 
Fantoni, S.
 and 
Murino, V.
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01162.x}

}
                
@article{
10.1111:j.1467-8659.2008.01164.x,

journal = {Computer Graphics Forum},
title = {{
Accurate Shadows by Depth Complexity Sampling}},

author = {
Forest, Vincent
 and 
Barthe, Loic
 and 
Paulin, Mathias
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01164.x}

}
                
@article{
10.1111:j.1467-8659.2008.01165.x,

journal = {Computer Graphics Forum},
title = {{
Deep Opacity Maps}},

author = {
Yuksel, Cem
 and 
Keyser, John
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01165.x}

}
                
@article{
10.1111:j.1467-8659.2008.01166.x,

journal = {Computer Graphics Forum},
title = {{
Practical Product Importance Sampling for Direct Illumination}},

author = {
Clarberg, Petrik
 and 
Akenine-Moeller, Tomas
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01166.x}

}
                
@article{
10.1111:j.1467-8659.2008.01167.x,

journal = {Computer Graphics Forum},
title = {{
Characterization for High Dynamic Range Imaging}},

author = {
Kim, Min H.
 and 
Kautz, Jan
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01167.x}

}
                
@article{
10.1111:j.1467-8659.2008.01168.x,

journal = {Computer Graphics Forum},
title = {{
Modeling a Generic Tone-mapping Operator}},

author = {
Mantiuk, Rafal
 and 
Seidel, Hans-Peter
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01168.x}

}
                
@article{
10.1111:j.1467-8659.2008.01169.x,

journal = {Computer Graphics Forum},
title = {{
Agile Spectrum Imaging: Programmable Wavelength Modulation for Cameras and Projectors}},

author = {
Mohan, Ankit
 and 
Raskar, Ramesh
 and 
Tumblin, Jack
},
year = {
2008},

publisher = {
The Eurographics Association and Blackwell Publishing Ltd},


ISSN = {1467-8659},

DOI = {
10.1111/j.1467-8659.2008.01169.x}

}

Browse

Recent Submissions

Now showing 1 - 59 of 59
  • Thumbnail Image
    Item
    Frontmatter
    (The Eurographics Association and Blackwell Publishing Ltd, 2008)
  • Thumbnail Image
    Item
    Reduced Depth and Visual Hulls of Complex 3D Scenes
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Bogomjakov, Alexander; Gotsman, Craig
    Depth and visual hulls are useful for quick reconstruction and rendering of a 3D object based on a number of reference views. However, for many scenes, especially multi-object, these hulls may contain significant artifacts known as phantom geometry. In depth hulls the phantom geometry appears behind the scene objects in regions occluded from all the reference views. In visual hulls the phantom geometry may also appear in front of the objects because there is not enough information to unambiguously imply the object positions.In this work we identify which parts of the depth and visual hull might constitute phantom geometry. We define the notion of reduced depth hull and reduced visual hull as the parts of the corresponding hull that are phantom-free. We analyze the role of the depth information in identification of the phantom geometry. Based on this, we provide an algorithm for rendering the reduced depth hull at interactive frame-rates and suggest an approach for rendering the reduced visual hull. The rendering algorithms take advantage of modern GPU programming techniques.Our techniques bypass explicit reconstruction of the hulls, rendering the reduced depth or visual hull directly from the reference views.
  • Thumbnail Image
    Item
    Surface Reconstruction From Non-parallel Curve Networks
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Liu, L.; Bajaj, C.; Deasy, J. O.; Low, D. A.; Ju, T.
    Building surfaces from cross-section curves has wide applications including bio-medical modeling. Previous work in this area has mostly focused on connecting simple closed curves on parallel cross-sections. Here we consider the more general problem where input data may lie on non-parallel cross-sections and consist of curve networks that represent the segmentation of the underlying object by different material or tissue types (e.g., skin, muscle, bone, etc.) on each cross-section. The desired output is a surface network that models both the exterior surface and the internal partitioning of the object. We introduce an algorithm that is capable of handling curve networks of arbitrary shape and topology on cross-section planes with arbitrary orientations. Our algorithm is simple to implement and is guaranteed to produce a closed surface network that interpolates the curve network on each cross-section. Our method is demonstrated on both synthetic and bio-medical examples.
  • Thumbnail Image
    Item
    High-Resolution Volumetric Computation of Offset Surfaces with Feature Preservation
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Pavic, Darko; Kobbelt, Leif
    We present a new algorithm for the efficient and reliable generation of offset surfaces for polygonal meshes. The algorithm is robust with respect to degenerate configurations and computes (self-)intersection free offsets that do not miss small and thin components. The results are correct within a prescribed ?-tolerance. This is achieved by using a volumetric approach where the offset surface is defined as the union of a set of spheres, cylinders, and prisms instead of surface-based approaches that generally construct an offset surface by shifting the input mesh in normal direction. Since we are using the unsigned distance field, we can handle any type of topological inconsistencies including non-manifold configurations and degenerate triangles. A simple but effective mesh operation allows us to detect and include sharp features (shocks) into the output mesh and to preserve them during post-processing (decimation and smoothing). We discretize the distance function by an efficient multi-level scheme on an adaptive octree data structure. The problem of limited voxel resolutions inherent to every volumetric approach is avoided by breaking the bounding volume into smaller tiles and processing them independently. This allows for almost arbitrarily high voxel resolutions on a commodity PC while keeping the output mesh complexity low. The quality and performance of our algorithm is demonstrated for a number of challenging examples.
  • Thumbnail Image
    Item
    Render2MPEG: A Perception-based Framework Towards Integrating Rendering and Video Compression
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Herzog, Robert; Kinuwaki, Shinichi; Myszkowski, Karol; Seidel, Hans-Peter
    Currently 3D animation rendering and video compression are completely independent processes even if rendered frames are streamed on-the-fly within a client-server platform. In such scenario, which may involve time-varying transmission bandwidths and different display characteristics at the client side, dynamic adjustment of the rendering quality to such requirements can lead to a better use of server resources. In this work, we present a framework where the renderer and MPEG codec are coupled through a straightforward interface that provides precise motion vectors from the rendering side to the codec and perceptual error thresholds for each pixel in the opposite direction. The perceptual error thresholds take into account bandwidth-dependent quantization errors resulting from the lossy com-pression as well as image content-dependent luminance and spatial contrast masking. The availability of the discrete cosine transform (DCT) coefficients at the codec side enables to use advanced models of the human visual system (HVS) in the perceptual error threshold derivation without incurring any significant cost. Those error thresholds are then used to control the rendering quality and make it well aligned with the compressed stream quality. In our prototype system we use the lightcuts technique developed by Walter et al., which we enhance to handle dynamic image sequences, and an MPEG-2 implementation. Our results clearly demonstrate many advantages of coupling the rendering with video compression in terms of faster rendering. Furthermore, temporally coherent rendering leads to a reduction of temporal artifacts.
  • Thumbnail Image
    Item
    Effect of Character Animacy and Preparatory Motion on Perceptual Magnitude of Errors in Ballistic Motion
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Reitsma, P. S. A.; Andrews, J.; Pollard, N. S.
    An increasing number of projects have examined the perceptual magnitude of visible artifacts in animated motion. These studies have been performed using a mix of character types, from detailed human models to abstract geometric objects such as spheres. We explore the extent to which character morphology influences user sensitivity to errors in a fixed set of ballistic motions replicated on three different character types. We find user sensitivity responds to changes in error type or magnitude in a similar manner regardless of character type, but that users display a higher sensitivity to some types of errors when these errors are displayed on more human-like characters. Further investigation of those error types suggests that being able to observe a period of preparatory motion before the onset of ballistic motion may be important. However, we found no evidence to suggest that a mismatch between the preparatory phase and the resulting ballistic motion was responsible for the higher sensitivity to errors that was observed for the most humanlike character.
  • Thumbnail Image
    Item
    Apparent Greyscale: A Simple and Fast Conversion to Perceptually Accurate Images and Video
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Smith, Kaleigh; Landes, Pierre-Edouard; Thollot, Joelle; Myszkowski, Karol
    This paper presents a quick and simple method for converting complex images and video to perceptually accurate greyscale versions. We use a two-step approach first to globally assign grey values and determine colour ordering, then second, to locally enhance the greyscale to reproduce the original contrast. Our global mapping is image independent and incorporates the Helmholtz-Kohlrausch colour appearance effect for predicting differences between isoluminant colours. Our multiscale local contrast enhancement reintroduces lost discontinuities only in regions that insufficiently represent original chromatic contrast. All operations are restricted so that they preserve the overall image appearance, lightness range and differences, colour ordering, and spatial details, resulting in perceptually accurate achromatic reproductions of the colour original.
  • Thumbnail Image
    Item
    Lighting and Occlusion in a Wave-Based Framework
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Ziegler, Remo; Croci, Simone; Gross, Markus
    We present novel methods to enhance Computer Generated Holography (CGH) by introducing a complex-valued wave-based occlusion handling method. This offers a very intuitive and efficient interface to introduce optical elements featuring physically-based light interaction exhibiting depth-of-field, diffraction, and glare effects. Fur-thermore, an efficient and flexible evaluation of lit objects on a full-parallax hologram leads to more convincing images. Previous illumination methods for CGH are not able to change the illumination settings of rendered holo-grams. In this paper we propose a novel method for real-time lighting of rendered holograms in order to change the appearance of a previously captured holographic scene. These functionalities are features of a bigger wave-based rendering framework which can be combined with 2D framebuffer graphics. We present an algorithm which uses graphics hardware to accelerate the rendering.
  • Thumbnail Image
    Item
    CHC++: Coherent Hierarchical Culling Revisited
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Mattausch, Oliver; Bittner, Jiri; Wimmer, Michael
    We present a new algorithm for efficient occlusion culling using hardware occlusion queries. The algorithm significantly improves on previous techniques by making better use of temporal and spatial coherence of visibility. This is achieved by using adaptive visibility prediction and query batching. As a result of the new optimizations the number of issued occlusion queries and the number of rendering state changes are significantly reduced. We also propose a simple method for determining tighter bounding volumes for occlusion queries and a method which further reduces the pipeline stalls. The proposed method provides up to an order of magnitude speedup over the previous state of the art. The new technique is simple to implement, does not rely on hardware calibration and integrates well with modern game engines.
  • Thumbnail Image
    Item
    GPU Accelerated Direct Volume Rendering on an Interactive Light Field Display
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Agus, Marco; Gobbetti, Enrico; Guitian, Jose Antonio Iglesias; Marton, Fabio; Pintore, Giovanni
    We present a GPU accelerated volume ray casting system interactively driving a multi-user light field display. The display, driven by a single programmable GPU, is based on a specially arranged array of projectors and a holographic screen and provides full horizontal parallax. The characteristics of the display are exploited to develop a specialized volume rendering technique able to provide multiple freely moving naked-eye viewers the illusion of seeing and manipulating virtual volumetric objects floating in the display workspace. In our approach, a GPU ray-caster follows rays generated by a multiple-center-of-projection technique while sampling pre-filtered versions of the dataset at resolutions that match the varying spatial accuracy of the display. The method achieves interactive performance and provides rapid visual understanding of complex volumetric data sets even when using depth oblivious compositing techniques.
  • Thumbnail Image
    Item
    Curvature-Domain Shape Processing
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Eigensatz, Michael; Sumner, Robert W.; Pauly, Mark
    We propose a framework for 3D geometry processing that provides direct access to surface curvature to facilitate advanced shape editing, filtering, and synthesis algorithms. The central idea is to map a given surface to the curvature domain by evaluating its principle curvatures, apply filtering and editing operations to the curvature distribution, and reconstruct the resulting surface using an optimization approach. Our system allows the user to prescribe arbitrary principle curvature values anywhere on the surface. The optimization solves a nonlinear least-squares problem to find the surface that best matches the desired target curvatures while preserving important properties of the original shape. We demonstrate the effectiveness of this processing metaphor with several applications, including anisotropic smoothing, feature enhancement, and multi-scale curvature editing.
  • Thumbnail Image
    Item
    Spectral Geometry Processing with Manifold Harmonics
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Vallet, B.; Levy, B.
    We present an explicit method to compute a generalization of the Fourier Transform on a mesh. It is well known that the eigenfunctions of the Laplace Beltrami operator (Manifold Harmonics) define a function basis allowing for such a transform. However, computing even just a few eigenvectors is out of reach for meshes with more than a few thousand vertices, and storing these eigenvectors is prohibitive for large meshes. To overcome these limitations, we propose a band-by-band spectrum computation algorithm and an out-of-core implementation that can compute thousands of eigenvectors for meshes with up to a million vertices. We also propose a limited-memory filtering algorithm, that does not need to store the eigenvectors. Using this latter algorithm, specific frequency bands can be filtered, without needing to compute the entire spectrum. Finally, we demonstrate some applications of our method to interactive convolution geometry filtering. These technical achievements are supported by a solid yet simple theoretic framework based on Discrete Exterior Calculus (DEC). In particular, the issues of symmetry and discretization of the operator are considered with great care.
  • Thumbnail Image
    Item
    Fast Force Field Approximation and its Application to Skeletonization of Discrete 3D Objects
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Brunner, D.; Brunnett, G.
    In this paper we present a novel method to approximate the force field of a discrete 3d object with a time complexity that is linear in the number of voxels. We define a rule, similar to the distance transform, to propagate forces associated with boundary points into the interior of the object. The result of this propagation depends on the order in which the points of the object are processed. Therefore we analyze how to obtain an order-invariant approximation formula. With the resulting formula it becomes possible to approximate the force field and to use its features for a fast and topology preserving skeletonization. We use a thinning strategy on the body-centered cubic lattice to compute the skeleton and ensure that critical points of the force field are not removed. This leads to improved skeletons with respect to the properties of centeredness and rotational invariance.
  • Thumbnail Image
    Item
    Video Relighting Using Infrared Illumination
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Wang, Oliver; Davis, James; Chuang, Erika; Rickard, Ian; De Mesa, Krystle; Dave, Chirag
    Inappropriate lighting is often responsible for poor quality video. In most offices and homes, lighting is not designed for video conferencing. This can result in unevenly lit faces, distracting shadows, and unnatural colors. We present a method for relighting faces that reduces the effects of uneven lighting and color. Our setup consists of a compact lighting rig and a camera that is both inexpensive and inconspicuous to the user. We use unperceivable infrared (IR) lights to obtain an illumination bases of the scene. Our algorithm computes an optimally weighted combination of IR bases to minimize lighting inconsistencies in foreground areas and reduce the effects of colored monitor light. However, IR relighting alone results in images with an unnatural ghostly appearance, thus a retargeting technique is presented which removes the unnatural IR effects and produces videos that have substantially more balanced intensity and color than the original video.
  • Thumbnail Image
    Item
    Stereo Light Probe
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Corsini, Massimiliano; Callieri, Marco; Cignoni, Paolo
    In this paper we present a practical, simple and robust method to acquire the spatially-varying illumination of a real-world scene. The basic idea of the proposed method is to acquire the radiance distribution of the scene using high-dynamic range images of two reflective balls. The use of two light probes instead of a single one allows to estimate, not only the direction and intensity of the light sources, but also the actual position in space of the light sources. To robustly achieve this goal we first rectify the two input spherical images, then, using a region-based stereo matching algorithm, we establish correspondences and compute the position of each light. The radiance distribution so obtained can be used for augmented reality applications, photo-realistic rendering and accurate reflectance properties estimation. The accuracy and the effectiveness of the method have been tested by measuring the computed light position and rendering synthetic version of a real object in the same scene. The comparison with standard method that uses a simple spherical lighting environment is also shown.
  • Thumbnail Image
    Item
    Augmented Panoramic Video
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Hermans, C.; Vanaken, C.; Mertens, T.; Van Reeth, F.; Bekaert, P.
    Many video sequences consist of a locally dynamic background containing moving foreground subjects. In this paper we propose a novel way of re-displaying these sequences, by giving the user control over a virtual camera frame. Based on video mosaicing, we first compute a static high quality background panorama. After segmenting and removing the foreground subjects from the original video, the remaining elements are merged into a dynamic background panorama, which seamlessly extends the original video footage. We then re-display this augmented video by warping and cropping the panorama. The virtual camera can have an enlarged field-of-view and a controlled camera motion. Our technique is able to process videos with complex camera motions, reconstructing high quality panoramas without parallax artefacts, visible seams or blurring, while retaining repetitive dynamic elements.
  • Thumbnail Image
    Item
    Sketching and Composing Widgets for 3D Manipulation
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Schmidt, Ryan; Singh, Karan; Balakrishnan, Ravin
    We present an interface for 3D object manipulation in which standard transformation tools are replaced with transient 3D widgets invoked by sketching context-dependent strokes. The widgets are automatically aligned to axes and planes determined by the user s stroke. Sketched pivot-points further expand the interaction vocabulary. Using gestural commands, these basic elements can be assembled into dynamic, user-constructed 3D transformation systems. We supplement precise widget interaction with techniques for coarse object positioning and snapping. Our approach, which is implemented within a broader sketch-based modeling system, also integrates an underlying widget history to enable the fluid transfer of widgets between objects. An evaluation indicates that users familiar with 3D manipulation concepts can be taught how to efficiently use our system in under an hour.
  • Thumbnail Image
    Item
    Real-Time Rendering and Editing of Vector-based Terrains
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Bruneton, Eric; Neyret, Fabrice
    We present a method to populate very large terrains with very detailed features such as roads, rivers, lakes and fields. These features can be interactively edited, and the landscape can be explored in real time at any altitude from flight view to car view. We use vector descriptions of linear and areal features, with associated shaders to specify their appearance (terrain color and material), their footprint (effect on terrain shape), and their associated objects (bridges, hedges, etc.).In order to encompass both very large terrains and very fine details we rely on a view dependent quadtree refinement scheme. New quads are generated when needed and cached on the GPU. For each quad we produce on the GPU an appearance texture, a footprint texture, and some object meshes, based on the features vector description and their associated shaders. Adaptive refinement, procedural vector features and a mipmap pyramid provide three LOD mechanisms for small, medium and large scale quads. Our results and attached video show high performance with high visual quality.
  • Thumbnail Image
    Item
    Sketch-Based Procedural Surface Modeling and Compositing Using Surface Trees
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Schmidt, Ryan; Singh, Karan
    We present a system for creating and manipulating layered procedural surface editing operations, which is motivated by the limited support for iterative design in free-form modeling. A combination of sketch-based and traditional modeling tools are used to design soft displacements, sharp creases, extrusions along 3D paths, and topological holes and handles. Using local parameterizations, these edits are combined in a dynamic hierarchy, enabling procedural operations like linked copy-and-paste and drag-and-drop layer-based editing. Such dynamic, layered surface compositing is formalized as a Surface Tree, an analog of CSG trees which generalizes previous hierarchical surface modeling techniques. By anchoring tree nodes in the parameter space of lower layers, our surface tree implementation can better preserve the semantics of an edit as the underlying surface changes. Details of our implementation are described, including an efficient procedural mesh data structure.
  • Thumbnail Image
    Item
    Hardware-Accelerated, High-Quality Rendering Based on Trivariate Splines Approximating Volume Data
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Kalbe, Thomas; Zeilfelder, Frank
    We develop an approach for hardware-accelerated, high-quality rendering of volume data using trivariate splines. The proposed quasi-interpolating schemes are realtime reconstructions. The low total degrees provide several advantages for our GPU implementation. In particular, intersecting rays with spline isosurfaces for direct Phong illumination is performed by simple root finding algorithms (analytic and iterative), while the necessary normals result from blossoming. Since visualizations are on a fragment base, our renderer for isosurfaces includes an automatic level of detail. While we use well-known spatial data structures in the CPU part of the algorithm for hierarchical view frustum culling and memory reduction, our GPU implementations have to take the highly complex structure of the splines into account. These include an appropriate organization of the data streams, i.e. we develop an advanced encoding scheme for the spline coefficients, as well as an implicit scheme for bounding geometry retrieval. In addition, we propose an elaborated clipping procedure to be performed in the fragment shader. These features essentially reduce bus traffic, memory consumption, and data access on the GPU leading to interactive frame rates for renderings of high visual quality. Compared with pure CPU implementations and existing GPU implementations for trivariate polynomials frame rates increase by factors between 10 and 100.
  • Thumbnail Image
    Item
    Zippy: A Framework for Computation and Visualization on a GPU Cluster
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Fan, Zhe; Qiu, Feng; Kaufman, Arie E.
    Due to its high performance/cost ratio, a GPU cluster is an attractive platform for large scale general-purpose computation and visualization applications. However, the programming model for high performance general-purpose computation on GPU clusters remains a complex problem. In this paper, we introduce the Zippy frame-work, a general and scalable solution to this problem. It abstracts the GPU cluster programming with a two-level parallelism hierarchy and a non-uniform memory access (NUMA) model. Zippy preserves the advantages of both message passing and shared-memory models. It employs global arrays (GA) to simplify the communication, synchronization, and collaboration among multiple GPUs. Moreover, it exposes data locality to the programmer for optimal performance and scalability. We present three example applications developed with Zippy: sort-last volume rendering, Marching Cubes isosurface extraction and rendering, and lattice Boltzmann flow simulation with online visualization. They demonstrate that Zippy can ease the development and integration of parallel visualization, graphics, and computation modules on a GPU cluster.
  • Thumbnail Image
    Item
    GPU-based Fast Ray Casting for a Large Number of Metaballs
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Kanamori, Yoshihiro; Szego, Zoltan; Nishita, Tomoyuki
    Metaballs are implicit surfaces widely used to model curved objects, represented by the isosurface of a density field defined by a set of points. Recently, the results of particle-based simulations have been often visualized using a large number of metaballs, however, such visualizations have high rendering costs. In this paper we propose a fast technique for rendering metaballs on the GPU. Instead of using polygonization, the isosurface is directly evaluated in a per-pixel manner. For such evaluation, all metaballs contributing to the isosurface need to be extracted along each viewing ray, on the limited memory of GPUs. We handle this by keeping a list of metaballs contributing to the isosurface and efficiently update it. Our method neither requires expensive precomputation nor acceleration data structures often used in existing ray tracing techniques. With several optimizations, we can display a large number of moving metaballs quickly.
  • Thumbnail Image
    Item
    Simulation of Human Motion Data using Short-Horizon Model-Predictive Control
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Da Silva, M.; Abe, Y.; Popovic, J.
    Many data-driven animation techniques are capable of producing high quality motions of human characters. Few techniques, however, are capable of generating motions that are consistent with physically simulated environments. Physically simulated characters, in contrast, are automatically consistent with the environment, but their motions are often unnatural because they are difficult to control. We present a model-predictive controller that yields natural motions by guiding simulated humans toward real motion data. During simulation, the predictive component of the controller solves a quadratic program to compute the forces for a short window of time into the future. These forces are then applied by a low-gain proportional-derivative component, which makes minor adjustments until the next planning cycle. The controller is fast enough for interactive systems such as games and training simulations. It requires no precomputation and little manual tuning. The controller is resilient to mismatches between the character dynamics and the input motion, which allows it to track motion capture data even where the real dynamics are not known precisely. The same principled formulation can generate natural walks, runs, and jumps in a number of different physically simulated surroundings.
  • Thumbnail Image
    Item
    Ray Casting Algebraic Surfaces using the Frustum Form
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Reimers, Martin; Seland, Johan
    We propose an algorithm for interactive ray-casting of algebraic surfaces of high degree. A key point of our approach is a polynomial form adapted to the view frustum. This so called frustum form yields simple expressions for the Bernstein form of the ray equations, which can be computed efficiently using matrix products and pre-computed quantities. Numerical root-finding is performed using B-spline and Bezier techniques, and we compare the performances of recent and classical algorithms. Furthermore, we propose a simple and fairly efficient anti-aliasing scheme, based on a combination of screen space and object space techniques. We show how our algorithms can be implemented on streaming architectures with single precision, and demonstrate interactive frame-rates for degrees up to 16.
  • Thumbnail Image
    Item
    Expressive Facial Gestures From Motion Capture Data
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Ju, Eunjung; Lee, Jehee
    Human facial gestures often exhibit such natural stochastic variations as how often the eyes blink, how often the eyebrows and the nose twitch, and how the head moves while speaking. The stochastic movements of facial features are key ingredients for generating convincing facial expressions. Although such small variations have been simulated using noise functions in many graphics applications, modulating noise functions to match natural variations induced from the affective states and the personality of characters is difficult and not intuitive. We present a technique for generating subtle expressive facial gestures (facial expressions and head motion) semi-automatically from motion capture data. Our approach is based on Markov random fields that are simulated in two levels. In the lower level, the coordinated movements of facial features are captured, parameterized, and transferred to synthetic faces using basis shapes. The upper level represents independent stochastic behavior of facial features. The experimental results show that our system generates expressive facial gestures synchronized with input speech.
  • Thumbnail Image
    Item
    Automatic Conversion of Mesh Animations into Skeleton-based Animations
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) De Aguiar, Edilson; Theobalt, Christian; Thrun, Sebastian; Seidel, Hans-Peter
    Recently, it has become increasingly popular to represent animations not by means of a classical skeleton-based model, but in the form of deforming mesh sequences. The reason for this new trend is that novel mesh deformation methods as well as new surface based scene capture techniques offer a great level of flexibility during animation creation. Unfortunately, the resulting scene representation is less compact than skeletal ones and there is not yet a rich toolbox available which enables easy post-processing and modification of mesh animations. To bridge this gap between the mesh-based and the skeletal paradigm, we propose a new method that automatically extracts a plausible kinematic skeleton, skeletal motion parameters, as well as surface skinning weights from arbitrary mesh animations. By this means, deforming mesh sequences can be fully-automatically transformed into fullyrigged virtual subjects. The original input can then be quickly rendered based on the new compact bone and skin representation, and it can be easily modified using the full repertoire of already existing animation tools.
  • Thumbnail Image
    Item
    Articulated Object Reconstruction and Markerless Motion Capture from Depth Video
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Pekelny, Yuri; Gotsman, Craig
    We present an algorithm for acquiring the 3D surface geometry and motion of a dynamic piecewise-rigid object using a single depth video camera. The algorithm identifies and tracks the rigid components in each frame, while accumulating the geometric information acquired over time, possibly from different viewpoints. The algorithm also reconstructs the dynamic skeleton of the object, thus can be used for markerless motion capture. The acquired model can then be animated to novel poses. We show the results of the algorithm applied to synthetic and real depth video.
  • Thumbnail Image
    Item
    Floating Textures
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Eisemann, M.; De Decker, B.; Magnor, M.; Bekaert, P.; De Aguiar, E.; Ahmed, N.; Theobalt, C.; Sellent, A.
    We present a novel multi-view, projective texture mapping technique. While previous multi-view texturing approaches lead to blurring and ghosting artefacts if 3D geometry and/or camera calibration are imprecise, we propose a texturing algorithm that warps ( floats ) projected textures during run-time to preserve crisp, detailed texture appearance. Our GPU implementation achieves interactive to real-time frame rates. The method is very generally applicable and can be used in combination with many image-based rendering methods or projective texturing applications. By using Floating Textures in conjunction with, e.g., visual hull rendering, light field rendering, or free-viewpoint video, improved rendering results are obtained from fewer input images, less accurately calibrated cameras, and coarser 3D geometry proxies.
  • Thumbnail Image
    Item
    Texture Synthesis From Photographs
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Eisenacher, C.; Lefebvre, S.; Stamminger, M.
    The goal of texture synthesis is to generate an arbitrarily large high-quality texture from a small input sample. Generally, it is assumed that the input image is given as a flat, square piece of texture, thus it has to be carefully prepared from a picture taken under ideal conditions. Instead we would like to extract the input texture from any surface from within an arbitrary photograph. This introduces several challenges: Only parts of the photograph are covered with the texture of interest, perspective and scene geometry introduce distortions, and the texture is non-uniformly sampled during the capture process. This breaks many of the assumptions used for synthesis.In this paper we combine a simple novel user interface with a generic per-pixel synthesis algorithm to achieve high-quality synthesis from a photograph. Our interface lets the user locally describe the geometry supporting the textures by combining rational Bezier patches. These are particularly well suited to describe curved surfaces under projection. Further, we extend per-pixel synthesis to account for arbitrary texture sparsity and distortion, both in the input image and in the synthesis output. Applications range from synthesizing textures directly from photographs to high-quality texture completion.
  • Thumbnail Image
    Item
    An Example-based Procedural System for Element Arrangement
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Ijiri, Takashi; Mech, Radomir; Igarashi, Takeo; Miller, Gavin
    We present a method for synthesizing two dimensional (2D) element arrangements from an example. The main idea is to combine texture synthesis techniques based-on a local neighborhood comparison and procedural modeling systems based-on local growth. Given a user-specified reference pattern, our system analyzes neigh-borhood information of each element by constructing connectivity. Our synthesis process starts with a single seed and progressively places elements one by one by searching a reference element which has local features that are the most similar to the target place of the synthesized pattern. To support creative design activities, we introduce three types of interaction for controlling global features of the resulting pattern, namely a spray tool, a flow field tool, and a boundary tool. We also introduce a global optimization process that helps to avoid local error concentrations. We illustrate the feasibility of our method by creating several types of 2D patterns.
  • Thumbnail Image
    Item
    Manifold-valued Thin-Plate Splines with Applications in Computer Graphics
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Steinke, Florian; Hein, Matthias; Peters, Jan; Schoelkopf, Bernhard
    We present a generalization of thin-plate splines for interpolation and approximation of manifold-valued data, and demonstrate its usefulness in computer graphics with several applications from different fields. The cornerstone of our theoretical framework is an energy functional for mappings between two Riemannian manifolds which is independent of parametrization and respects the geometry of both manifolds. If the manifolds are Euclidean, the energy functional reduces to the classical thin-plate spline energy. We show how the resulting optimization problems can be solved efficiently in many cases. Our example applications range from orientation interpolation and motion planning in animation over geometric modelling tasks to color interpolation.
  • Thumbnail Image
    Item
    Conformal Flattening by Curvature Prescription and Metric Scaling
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Ben-Chen, Mirela; Gotsman, Craig; Bunin, Guy
    We present an efficient method to conformally parameterize 3D mesh data sets to the plane. The idea behind our method is to concentrate all the 3D curvature at a small number of select mesh vertices, called cone singularities, and then cut the mesh through those singular vertices to obtain disk topology. The singular vertices are chosen automatically. As opposed to most previous methods, our flattening process involves only the solution of linear systems of Poisson equations, thus is very efficient. Our method is shown to be faster than existing methods, yet generates parameterizations having comparable quasi-conformal distortion.
  • Thumbnail Image
    Item
    Higher Order Barycentric Coordinates
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Langer, Torsten; Seidel, Hans-Peter
    In recent years, a wide range of generalized barycentric coordinates has been suggested. However, all of them lack control over derivatives. We show how the notion of barycentric coordinates can be extended to specify derivatives at control points. This is also known as Hermite interpolation. We introduce a method to modify existing barycentric coordinates to higher order barycentric coordinates and demonstrate, using higher order mean value coordinates, that our method, although conceptually simple and easy to implement, can be used to give easy and intuitive control at interactive frame rates over local space deformations such as rotations.
  • Thumbnail Image
    Item
    A Semi-Lagrangian CIP Fluid Solver without Dimensional Splitting
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Kim, Doyub; Song, Oh-young; Ko, Hyeong-Seok
    In this paper, we propose a new constrained interpolation profile (CIP) method that is stable and accurate but requires less amount of computation compared to existing CIP-based solvers. CIP is a high-order fluid advection solver that can reproduce rich details of fluids. It has third-order accuracy but its computation is performed over a compact stencil. These advantageous features of CIP are, however, diluted by the following two shortcomings: (1) CIP contains a defect in the utilization of the grid data, which makes the method suitable only for simulations with a tight CFL restriction; and (2) CIP does not guarantee unconditional stability. There have been several attempts to fix these problems in CIP, but they have been only partially successful. The solutions that fixed both problems ended up introducing other undesirable features, namely increased computation time and/or reduced accuracy. This paper proposes a novel modification of the original CIP method that fixes all of the above problems without increasing the computational load or reducing the accuracy. Both quantitative and visual experiments were performed to test the performance of the new CIP in comparison to existing fluid solvers. The results show that the proposed method brings significant improvements in both accuracy and speed.
  • Thumbnail Image
    Item
    Fluid in Video: Augmenting Real Video with Simulated Fluids
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Kwatra, Vivek; Mordohai, Philippos; Narain, Rahul; Penta, Sashi Kumar; Carlsonk, Mark; Pollefeys, Marc; Lin, Ming C.
    We present a technique for coupling simulated fluid phenomena that interact with real dynamic scenes captured as a binocular video sequence. We first process the binocular video sequence to obtain a complete 3D reconstruction of the scene, including velocity information. We use stereo for the visible parts of 3D geometry and surface completion to fill the missing regions. We then perform fluid simulation within a 3D domain that contains the object, enabling one-way coupling from the video to the fluid. In order to maintain temporal consistency of the reconstructed scene and the animated fluid across frames, we develop a geometry tracking algorithm that combines optic flow and depth information with a novel technique for velocity completion . The velocity completion technique uses local rigidity constraints to hypothesize a motion field for the entire 3D shape, which is then used to propagate and filter the reconstructed shape over time. This approach not only generates smoothly varying geometry across time, but also simultaneously provides the necessary boundary conditions for one-way coupling between the dynamic geometry and the simulated fluid. Finally, we employ a GPU based scheme for rendering the synthetic fluid in the real video, taking refraction and scene texture into account.
  • Thumbnail Image
    Item
    A Fast Simulation Method Using Overlapping Grids for Interactions between Smoke and Rigid Objects
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Dobashi, Yoshinori; Matsuda, Yasuhiro; Yamamoto, Tsuyoshi; Nishita, Tomoyuki
    Recently, many techniques using computational fluid dynamics have been proposed for the simulation of natural phenomena such as smoke and fire. Traditionally, a single grid is used for computing the motion of fluids. When an object interacts with a fluid, the resolution of the grid must be sufficiently high because the shape of the object is represented by a shape sampled at the grid points. This increases the number of grid points that are required, and hence the computational cost is increased. To address this problem, we propose a method using multiple grids that overlap with each other. In addition to a large single grid (a global grid) that covers the whole of the simulation space, separate grids (local grids) are generated that surround each object. The resolution of a local grid is higher than that of the global grid. The local grids move according to the motion of the objects. Therefore, the process of resampling the shape of the object is unnecessary when the object moves. To accelerate the computation, appropriate resolutions are adaptively-determined for the local grids according to their distance from the viewpoint. Furthermore, since we use regular (orthogonal) lattices for the grids, the method is suitable for GPU implementation. This realizes the real-time simulation of interactions between objects and smoke.
  • Thumbnail Image
    Item
    An Adaptive Contact Model for the Robust Simulation of Knots
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Spillmann, Jonas; Teschner, Matthias
    In this paper, we present an adaptive model for dynamically deforming hyper-elastic rods. In contrast to existing approaches, adaptively introduced control points are not governed by geometric subdivision rules. Instead, their states are determined by employing a non-linear energy-minimization approach. Since valid control points are computed instantaneously, post-stabilization schemes are avoided and the stability of the dynamic simulation is improved.Due to inherently complex contact configurations, the simulation of knot tying using rods is a challenging task. In order to address this problem, we combine our adaptive model with a robust and accurate collision handling method for elastic rods. By employing our scheme, complex knot configurations can be simulated in a physically plausible way.
  • Thumbnail Image
    Item
    Single-pass Scalable Subsurface Rendering with Lightcuts
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Arbree, Adam; Walter, Bruce; Bala, Kavita
    This paper presents a new, scalable, single pass algorithm for computing subsurface scattering using the diffusion approximation. Instead of pre-computing a globally conservative estimate of the surface irradiance like previous two pass methods, the algorithm simultaneously refines hierarchical and adaptive estimates of both the surface irradiance and the subsurface transport. By using an adaptive, top-down refinement method, the algorithm directs computational effort only to simulating those eye-surface-light paths that make significant contributions to the final image. Because the algorithm is driven by image importance, it scales more efficiently than previous methods that have a linear dependence on translucent surface area. We demonstrate that in scenes with many translucent objects and in complex lighting environments, our new algorithm has a significant performance advantage.
  • Thumbnail Image
    Item
    Real-Time Translucent Rendering Using GPU-based Texture Space Importance Sampling
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Chang, Chih-Wen; Lin, Wen-Chieh; Ho, Tan-Chi; Huang, Tsung-Shian; Chuang, Jung-Hong
    We present a novel approach for real-time rendering of translucent surfaces. The computation of subsurface scattering is performed by first converting the integration over the 3D model surface into an integration over a 2D texture space and then applying importance sampling based on the irradiance stored in the texture. Such a conversion leads to a feasible GPU implementation and makes real-time frame rate possible. Our implementation shows that plausible images can be rendered in real time for complex translucent models with dynamic light and material properties. For objects with more apparent local effect, our approach generally requires more samples that may downgrade the frame rate. To deal with this case, we decompose the integration into two parts, one for local effect and the other for global effect, which are evaluated by the combination of available methods [DS03, MKB* 03a] and our texture space importance sampling, respectively. Such a hybrid scheme is able to steadily render the translucent effect in real time with a fixed amount of samples.
  • Thumbnail Image
    Item
    Photo-realistic Rendering of Metallic Car Paint from Image-Based Measurements
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Rump, Martin; Mueller, Gero; Sarlette, Ralf; Koch, Dirk; Klein, Reinhard
    State-of-the-art car paint shows not only interesting and subtle angular dependency but also significant spatial variation. Especially in sunlight these variations remain visible even for distances up to a few meters and give the coating a strong impression of depth which cannot be reproduced by a single BRDF model and the kind of procedural noise textures typically used. Instead of explicitly modeling the responsible effect particles we propose to use image-based reflectance measurements of real paint samples and represent their spatial varying part by Bidirectional Texture Functions (BTF). We use classical BRDF models like Cook-Torrance to represent the reflection behavior of the base paint and the highly specular finish and demonstrate how the parameters of these models can be derived from the BTF measurements. For rendering, the image-based spatially varying part is compressed and efficiently synthesized. This paper introduces the first hybrid analytical and image-based representation for car paint and enables the photo-realistic rendering of all significant effects of highly complex coatings.
  • Thumbnail Image
    Item
    Efficient and Dynamic Simplification of Line Drawings
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Shesh, Amit; Chen, Baoquan
    In this paper we present a pipeline for rendering dynamic 2D/3D line drawings efficiently. Our main goal is to create efficient static renditions and coherent animations of line drawings in a setting where lines can be added, deleted and arbitrarily transformed on-the-fly. Such a dynamic setting enables us to handle interactively sketched 2D line data, as well as arbitrarily transformed 3D line data in a unified manner. We evaluate the proximity of screen projected strokes to simplify them while preserving their continuity. We achieve this by using a special data structure that facilitates efficient proximity calculations in a dynamic setting. This on-the-fly proximity evaluation also facilitates generation of appropriate visibility cues to mitigate depth ambiguities and visual clutter for 3D line data. As we perform all these operations using only line data, we can create line drawings from 3D models without any surface information. We demonstrate the effectiveness and applicability of our approach by showing several examples with initial line representations obtained from a variety of sources: 2D and 3D hand-drawn sketches and 3D salient geometry lines obtained from 3D surface representations.
  • Thumbnail Image
    Item
    Visualizing Underwater Ocean Optics
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Gutierrez, Diego; Seron, Francisco J.; Munoz, Adolfo; Anson, Oscar
    Simulating the in-water ocean light field is a daunting task. Ocean waters are one of the richest participating media, where light interacts not only with water molecules, but with suspended particles and organic matter as well. The concentration of each constituent greatly affects these interactions, resulting in very different hues. Inelastic scattering events such as fluorescence or Raman scattering imply energy transfers that are usually neglected in the simulations. Our contributions in this paper are a bio-optical model of ocean waters suitable for computer graphics simulations, along with an improved method to obtain an accurate solution of the in-water light field based on radiative transfer theory. The method provides a link between the inherent optical properties that define the medium and its apparent optical properties, which describe how it looks. The bio-optical model of the ocean uses published data from oceanography studies. For inelastic scattering we compute all frequency changes at higher and lower energy values, based on the spectral quantum efficiency function of the medium. The results shown prove the usability of the system as a predictive rendering algorithm. Areas of application for this research span from underwater imagery to remote sensing; the resolution method is general enough to be usable in any type of participating medium simulation.
  • Thumbnail Image
    Item
    The Beam Radiance Estimate for Volumetric Photon Mapping
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Jarosz, Wojciech; Zwicker, Matthias; Jensen, Henrik Wann
    We present a new method for efficiently simulating the scattering of light within participating media. Using a theoretical reformulation of volumetric photon mapping, we develop a novel photon gathering technique for participating media. Traditional volumetric photon mapping samples the in-scattered radiance at numerous points along the length of a single ray by performing costly range queries within the photon map. Our technique replaces these multiple point-queries with a single beam-query, which explicitly gathers all photons along the length of an entire ray. These photons are used to estimate the accumulated in-scattered radiance arriving from a particular direction and need to be gathered only once per ray. Our method handles both fixed and adaptive kernels, is faster than regular volumetric photon mapping, and produces images with less noise.
  • Thumbnail Image
    Item
    The Shadow Meets the Mask: Pyramid-Based Shadow Removal
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Shor, Yael; Lischinski, Dani
    In this paper we propose a novel method for detecting and removing shadows from a single image thereby obtaining a high-quality shadow-free image. With minimal user assistance, we first identify shadowed and lit areas on the same surface in the scene using an illumination-invariant distance measure. These areas are used to estimate the parameters of an affine shadow formation model. A novel pyramid-based restoration process is then applied to produce a shadow-free image, while avoiding loss of texture contrast and introduction of noise. Unlike previous approaches, we account for varying shadow intensity inside the shadowed region by processing it from the interior towards the boundaries. Finally, to ensure a seamless transition between the original and the recovered regions we apply image inpainting along a thin border. We demonstrate that our approach produces results that are in most cases superior in quality to those of previous shadow removal methods. We also show that it is possible to easily composite the extracted shadow onto a new background or modify its size and direction in the original image.
  • Thumbnail Image
    Item
    Interactive Volume Rendering with Dynamic Ambient Occlusion and Color Bleeding
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Ropinski, Timo; Meyer-Spradow, Jennis; Diepenbrock, Stefan; Mensmann, Joerg; Hinrichs, Klaus
    We propose a method for rendering volumetric data sets at interactive frame rates while supporting dynamic ambient occlusion as well as an approximation to color bleeding. In contrast to ambient occlusion approaches for polygonal data, techniques for volumetric data sets have to face additional challenges, since by changing rendering parameters, such as the transfer function or the thresholding, the structure of the data set and thus the light interactions may vary drastically. Therefore, during a preprocessing step which is independent of the rendering parameters we capture light interactions for all combinations of structures extractable from a volumetric data set. In order to compute the light interactions between the different structures, we combine this preprocessed information during rendering based on the rendering parameters defined interactively by the user. Thus our method supports interactive exploration of a volumetric data set but still gives the user control over the most important rendering parameters. For instance, if the user alters the transfer function to extract different structures from a volumetric data set the light interactions between the extracted structures are captured in the rendering while still allowing interactive frame rates. Compared to known local illumination models for volume rendering our method does not introduce any substantial rendering overhead and can be integrated easily into existing volume rendering applications. In this paper we will explain our approach, discuss the implications for interactive volume rendering and present the achieved results.
  • Thumbnail Image
    Item
    Detail-In-Context Visualization for Satellite Imagery
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Boettger, Joachim; Preiser, Martin; Balzer, Michael; Deussen, Oliver
    We use the complex logarithm as a transformation for the visualization and navigation of highly complex satellite and aerial imagery. The resulting depictions show details and context with greatly different scales in one seamless image while avoiding local distortions. We motivate our approach by showing its relations to the ordinary perspective views and classical map projections. We discuss how to organize and process the huge amount of imagery in realtime using modern graphics hardware with an extended clipmapping technique. Finally, we provide details and experiences concerning the interpretation of and interaction with the resulting representations.
  • Thumbnail Image
    Item
    Viewfinder Alignment
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Adams, Andrew; Gelfand, Natasha; Pulli, Kari
    The viewfinder of a digital camera has traditionally been used for one purpose: to display to the user a preview of what is seen through the camera s lens. High quality cameras are now available on devices such as mobile phones and PDAs, which provide a platform where the camera is a programmable device, enabling applications such as online computational photography, computer vision-based interactive gaming, and augmented reality. For such online applications, the camera viewfinder provides the user s main interaction with the environment. In this paper, we describe an algorithm for aligning successive viewfinder frames. First, an estimate of inter-frame translation is computed by aligning integral projections of edges in two images. The estimate is then refined to compute a full 2D similarity transformation by aligning point features. Our algorithm is robust to noise, never requires storing more than one viewfinder frame in memory, and runs at 30 frames per second on standard smartphone hardware. We use viewfinder alignment for panorama capture, low-light photography, and a camera-based game controller.
  • Thumbnail Image
    Item
    Image-based Aging Using Evolutionary Computing
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Hubball, Daniel; Chen, Min; Grant, Phil W.
    Aging has considerable visual effects on the human face and is difficult to simulate using a universally-applicable global model. In this paper, we focus on the hypothesis that the patterns of age progression (and regression) are related to the face concerned, as the latter implicitly captures the characteristics of gender, ethnic origin, and age group, as well as possibly the person-specific development patterns of the individual. We use a data-driven framework for automatic image-based facial transformation in conjunction with a database of facial images. We build a novel parameterized model for encoding age-transformation in addition with the traditional model for face description. We utilize evolutionary computing to learn the relationship between the two models. To support this work, we also developed a new image warping algorithm based on non-uniform radial basis functions (NURBFs). Evolutionary computing was also used to handle the large parameter space associated with NURBFs. In comparison with several different methods, it consistently provides the best results against the ground truth.
  • Thumbnail Image
    Item
    Image-based Material Weathering
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Xuey, Su; Wang, Jiaping; Tong, Xin; Dai, Qionghai; Guo, Baining
    The appearance manifold [WTL*06] is an efficient approach for modeling and editing time-variant appearance of materials from the BRDF data captured at single time instance. However, this method is difficult to apply in images in which weathering and shading variations are combined. In this paper, we present a technique for modeling and editing the weathering effects of an object in a single image with appearance manifolds. In our approach, we formulate the input image as the product of reflectance and illuminance. An iterative method is then developed to construct the appearance manifold in color space (i.e., Lab space) for modeling the reflectance variations caused by weathering. Based on the appearance manifold, we propose a statistical method to robustly decompose reflectance and illuminance for each pixel. For editing, we introduce a pixel-walking scheme to modify the pixel reflectance according to its position on the manifold, by which the detailed reflectance variations are well preserved. We illustrate our technique in various applications, including weathering transfer between two images that is first enabled by our technique. Results show that our technique can produce much better results than existing methods, especially for objects with complex geometry and shading effects.
  • Thumbnail Image
    Item
    Dynamic Sampling and Rendering of Algebraic Point Set Surfaces
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Guennebaud, Gael; Germann, Marcel; Gross, Markus
    Algebraic Point Set Surfaces (APSS) define a smooth surface from a set of points using local moving least-squares (MLS) fitting of algebraic spheres. In this paper we first revisit the spherical fitting problem and provide a new, more generic solution that includes intuitive parameters for curvature control of the fitted spheres. As a second contribution we present a novel real-time rendering system of such surfaces using a dynamic up-sampling strategy combined with a conventional splatting algorithm for high quality rendering. Our approach also includes a new view dependent geometric error tailored to efficient and adaptive up-sampling of the surface. One of the key features of our system is its high degree of flexibility that enables us to achieve high performance even for highly dynamic data or complex models by exploiting temporal coherence at the primitive level. We also address the issue of efficient spatial search data structures with respect to construction, access and GPU friendliness. Finally, we present an efficient parallel GPU implementation of the algorithms and search structures.
  • Thumbnail Image
    Item
    Distortion-Free Steganography for Polygonal Meshes
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Bogomjakov, Alexander; Gotsman, Craig; Isenburg, Martin
    We present a technique for steganography in polygonal meshes. Our method hides a message in the indexed rep-resentation of a mesh by permuting the order in which faces and vertices are stored. The permutation is relative to a reference ordering that encoder and decoder derive from the mesh connectivity in a consistent manner. Our method is distortion-free because it does not modify the geometry of the mesh. Compared to previous steganographic methods for polygonal meshes our capacity is up to an order of magnitude better.Our steganography algorithm is universal and can be used instead of the standard permutation steganography algorithm on arbitrary datasets. The standard algorithm runs in (n2 log2 n log log n) time and achieves optimal O(nlog n) bit capacity on datasets with n elements. In contrast, our algorithm runs in O(n) time, achieves a capacity that is only one bit per element less than optimal, and is extremely simple to implement.
  • Thumbnail Image
    Item
    Image-based Shaving
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Nguyen, Minh Hoai; Lalonde, Jean-Francois; Efros, Alexei A.; De la Torre, Fernando
    Many categories of objects, such as human faces, can be naturally viewed as a composition of several different layers. For example, a bearded face with glasses can be decomposed into three layers: a layer for glasses, a layer for the beard and a layer for other permanent facial features. While modeling such a face with a linear subspace model could be very difficult, layer separation allows for easy modeling and modification of some certain structures while leaving others unchanged. In this paper, we present a method for automatic layer extraction and its applications to face synthesis and editing. Layers are automatically extracted by utilizing the differences between subspaces and modeled separately. We show that our method can be used for tasks such beard removal (virtual shaving), beard synthesis, and beard transfer, among others.
  • Thumbnail Image
    Item
    Sparse points matching by combining 3D mesh saliency with statistical descriptors
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Castellani, U.; Cristani, M.; Fantoni, S.; Murino, V.
    This paper proposes new methodology for the detection and matching of salient points over several views of an object. The process is composed by three main phases. In the first step, detection is carried out by adopting a new perceptually-inspired 3D saliency measure. Such measure allows the detection of few sparse salient points that characterize distinctive portions of the surface. In the second step, a statistical learning approach is considered to describe salient points across different views. Each salient point is modelled by a Hidden Markov Model (HMM), which is trained in an unsupervised way by using contextual 3D neighborhood information, thus providing a robust and invariant point signature. Finally, in the third step, matching among points of different views is performed by evaluating a pairwise similarity measure among HMMs. An extensive and comparative experimental session has been carried out, considering real objects acquired by a 3D scanner from different points of view, where objects come from standard 3D databases. Results are promising, as the detection of salient points is reliable, and the matching is robust and accurate.
  • Thumbnail Image
    Item
    Accurate Shadows by Depth Complexity Sampling
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Forest, Vincent; Barthe, Loic; Paulin, Mathias
    The accurate generation of soft shadows is a particularly computationally intensive task. In order to reduce rendering time, most real-time and offline applications decorrelate the generation of shadows from the computation of lighting. In addition to such approximations, they generate shadows using some restrictive assumptions only correct in very specific cases, leading to penumbra over-estimation or light-leaking artifacts. In this paper we present an algorithm that produces soft shadows without exhibiting the previous drawbacks. Using a new efficient evaluation of the number of occluders between two points (i.e. the depth complexity) we either modulate direct lighting or numerically solve the rendering equation for direct illumination. Our approach approximates shadows cast by semi-opaque occluders and naturally handles area lights with spatially varying luminance. Furthermore, depending on the desired performance and quality, the resulting shadows are either very close to, or as accurate as, a ray-traced reference. As a result, the presented method is well suited to many domains, ranging from quality-sensitive to performance-critical applications.
  • Thumbnail Image
    Item
    Deep Opacity Maps
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Yuksel, Cem; Keyser, John
    We present a new method for rapidly computing shadows from semi-transparent objects like hair. Our deep opacity maps method extends the concept of opacity shadow maps by using a depth map to obtain a per pixel distribution of opacity layers. This approach eliminates the layering artifacts of opacity shadow maps and requires far fewer layers to achieve high quality shadow computation. Furthermore, it is faster than the density clustering technique, and produces less noise with comparable shadow quality. We provide qualitative comparisons to these previous methods and give performance results. Our algorithm is easy to implement, faster, and more memory efficient, enabling us to generate high quality hair shadows in real-time using graphics hardware on a standard PC.
  • Thumbnail Image
    Item
    Practical Product Importance Sampling for Direct Illumination
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Clarberg, Petrik; Akenine-Moeller, Tomas
    We present a practical algorithm for sampling the product of environment map lighting and surface reflectance. Our method builds on wavelet-based importance sampling, but has a number of important advantages over previous methods. Most importantly, we avoid using precomputed reflectance functions by sampling the BRDF on-the-fly. Hence, all types of materials can be handled, including anisotropic and spatially varying BRDFs, as well as procedural shaders. This also opens up for using very high resolution, uncompressed, environment maps. Our results show that this gives a significant reduction of variance compared to using lower resolution approximations. In addition, we study the wavelet product, and present a faster algorithm geared for sampling purposes. For our application, the computations are reduced to a simple quadtree-based multiplication. We build the BRDF approximation and evaluate the product in a single tree traversal, which makes the algorithm both faster and more flexible than previous methods.
  • Thumbnail Image
    Item
    Characterization for High Dynamic Range Imaging
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Kim, Min H.; Kautz, Jan
    In this paper we present a new practical camera characterization technique to improve color accuracy in high dynamic range (HDR) imaging. Camera characterization refers to the process of mapping device-dependent signals, such as digital camera RAW images, into a well-defined color space. This is a well-understood process for low dynamic range (LDR) imaging and is part of most digital cameras - usually mapping from the raw camera signal to the sRGB or Adobe RGB color space. This paper presents an efficient and accurate characterization method for high dynamic range imaging that extends previous methods originally designed for LDR imaging. We demonstrate that our characterization method is very accurate even in unknown illumination conditions, effectively turning a digital camera into a measurement device that measures physically accurate radiance values - both in terms of luminance and color - rivaling more expensive measurement instruments.
  • Thumbnail Image
    Item
    Modeling a Generic Tone-mapping Operator
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Mantiuk, Rafal; Seidel, Hans-Peter
    Although several new tone-mapping operators are proposed each year, there is no reliable method to validate their performance or to tell how different they are from one another. In order to analyze and understand the behavior of tone-mapping operators, we model their mechanisms by fitting a generic operator to an HDR image and its tone-mapped LDR rendering. We demonstrate that the majority of both global and local tone-mapping operators can be well approximated by computationally inexpensive image processing operations, such as a per-pixel tone curve, a modulation transfer function and color saturation adjustment. The results produced by such a generic tone-mapping algorithm are often visually indistinguishable from much more expensive algorithms, such as the bilateral filter. We show the usefulness of our generic tone-mapper in backward-compatible HDR image compression, the black-box analysis of existing tone mapping algorithms and the synthesis of new algorithms that are combination of existing operators.
  • Thumbnail Image
    Item
    Agile Spectrum Imaging: Programmable Wavelength Modulation for Cameras and Projectors
    (The Eurographics Association and Blackwell Publishing Ltd, 2008) Mohan, Ankit; Raskar, Ramesh; Tumblin, Jack
    We advocate the use of quickly-adjustable, computer-controlled color spectra in photography, lighting and displays. We present an optical relay system that allows mechanical or electronic color spectrum control and use it to modify a conventional camera and projector. We use a diffraction grating to disperse the rays into different colors, and introduce a mask (or LCD/DMD) in the optical path to modulate the spectrum. We analyze the trade-offs and limitations of this design, and demonstrate its use in a camera, projector and light source. We propose applications such as adaptive color primaries, metamer detection, scene contrast enhancement, photographing fluorescent objects, and high dynamic range photography using spectrum modulation.