Short Papers

Permanent URI for this collection

https://diglib.eg.org/handle/10.2312/271
Frontmatter

Preface and Table of Contents

[meta data] [files:
000_short_frontmatter.pdf
]
Alliez, P.
; 
Magnor, M.
Imaging, Perception, Display

Bilateral Filter Based Compositing for Variable Exposure Photography

[meta data] [files:
001-004.pdf ,
1.bmp ,
2.bmp ,
3.bmp ,
4.bmp
]
Raman, Shanmuganathan
; 
Chaudhuri, Subhasis
Imaging, Perception, Display

Depth of Field in Plenoptic Cameras

[meta data] [files:
005-008.pdf ,
all_in_focus.jpg ,
input.jpg ,
stereo.jpg
]
Georgiev, Todor
; 
Lumsdaine, Andrew
Imaging, Perception, Display

Real-time Vision-based Lateral Drift Correction

[meta data] [files:
013-016.pdf ,
rtvbldc.mov
]
Hübner, Thomas
; 
Pajarola, Renato
Imaging, Perception, Display

A Gaze-Contingent Display Compensating for Scotomata

[meta data] [files:
009-012.pdf
]
Duchowski, Andrew T.
; 
Eaddy, Tiras D.
Imaging, Perception, Display

Continuous Search and Replace in Vector Graphics

[meta data] [files:
017-020.pdf ,
search_and_replace.pdf
]
Loviscach, Joern
Imaging, Perception, Display

Multisampled Antialiasing of Per-pixel Geometry

[meta data] [files:
021-024.pdf
]
Schwarz, Michael
; 
Stamminger, Marc
Animation/ Modeling

Levels of Real-Time Crowd Navigation Behaviour in Urban Environments

[meta data] [files:
029-032.pdf
]
Haciomeroglu, Murat
; 
Laycock, Robert G.
; 
Day, Andrew M.
Animation/ Modeling

A Dynamic Caching System for Rendering an Animated Crowd in Real-Time

[meta data] [files:
025-028.pdf
]
Lister, Wayne
; 
Laycock, Robert G.
; 
Day, Andrew M.
Animation/ Modeling

Does Brief Exposure to a Self-avatar Effect Common Human Behaviors in Immersive Virtual Environments?

[meta data] [files:
033-036.pdf ,
avatar_med.wmv
]
Streuber, Stephan
; 
Rosa, Stephan de la
; 
Trutoiu, Laura
; 
Bülthoff, Heinrich H.
; 
Mohler, Betty J.
Animation/ Modeling

Volume Conserving Simulation of Deformable Bodies

[meta data] [files:
037-040.pdf ,
deformablebodystrongsprings.mp4 ,
deformablebodystrongsprings.mpg ,
deformablebodyweakstrings.mp4 ,
deformablebodyweakstrings.mpg
]
Diziol, Raphael
; 
Bender, Jan
; 
Bayer, Daniel
Rendering

A Cost Metric for Scene-Interior Ray Origins

[meta data] [files:
049-052.pdf
]
Fabianowski, Bartosz
; 
Fowler, Colin
; 
Dingliana, John
Animation/ Modeling

Video-Realistic Image-based Eye Animation System

[meta data] [files:
041-044.pdf
]
Weissenfeld, Axel
; 
Liu, Kang
; 
Ostermann, J.
Animation/ Modeling

Procedural City Layout Generation Based on Urban Land Use Models

[meta data] [files:
045-048.pdf
]
Groenewegen, Saskia A.
; 
Smelik, Ruben M.
; 
Kraker, Klaas Jan de
; 
Bidarra, Rafael
Rendering

Fast Approximation of Multiple Scattering in Inhomogeneous Participating Media

[meta data] [files:
053-056.pdf ,
compare.avi ,
head.avi
]
Szirmay-Kalos, László
; 
Liktor, Gábor
; 
Umenhoffer, Tamás
; 
Tóth, Balázs
Rendering

Real-time Volumetric Lighting in Participating Media

[meta data] [files:
057-060.pdf ,
volmedia.avi
]
Toth, Balazs
; 
Umenhoffer, Tamas
Rendering

A Precalculated Point Set for Caching Shading Information

[meta data] [files:
065-068.pdf
]
Bikker, Jacco
; 
Reijerse, Roel
Rendering

Importance Sampling with Floyd-Steinberg Halftoning

[meta data] [files:
069-072.pdf
]
Szirmay-Kalos, László
; 
Szécsi, László
; 
Penzov, Anton
Rendering

Fast Rendering of Particle-Based Fluid by Utilizing Simulation Data

[meta data] [files:
061-064.pdf ,
eg_1mparticles.mov ,
eg_1m_blend.tif ,
eg_realtime.mov
]
Yasuda, Ren
; 
Harada, Takahiro
; 
Kawaguchi, Yoichiro
Geometry and Images

Noise Robust Surface Reconstruction by Combining PU and Graph-cut

[meta data] [files:
073-076.pdf
]
Nagai, Yukie
; 
Ohtake, Yutaka
; 
Suzuki, Hiromasa
Geometry and Images

A new Projection Method for Point Set Surfaces

[meta data] [files:
077-080.pdf
]
Kalbe, Thomas
; 
Fuhrmann, Simon
; 
Uhrig, Stefan
; 
Zeilfelder, Frank
; 
Kuijper, Arjan
Geometry and Images

Dent Removal: Geodesic Curve-Based Mesh Fairing

[meta data] [files:
081-084.pdf ,
dentremovalvideo.mp4
]
Pinskiy, Dmitriy
Geometry and Images

Tile-based Image Forces for Active Contours on GPU

[meta data] [files:
089-092.pdf
]
Kienel, Enrico
; 
Brunnett, Guido
Geometry and Images

A Real-time Interactive Tool for Image Cutout

[meta data] [files:
085-088.pdf
]
Liu, Chen
; 
Li, Fengxia
; 
Zhang, Yan
; 
Zhan, Shouyi
Geometry and Images

Improving Interactive Image Segmentation via Appearance Propagation

[meta data] [files:
093-096.pdf
]
Pan, Wei

BibTeX (Short Papers)
@inproceedings{
10.2312:egs.20091033,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Preface and Table of Contents}},

author = {
Alliez, P.
 and 
Magnor, M.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091033}

}
@inproceedings{
10.2312:egs.20091034,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Bilateral Filter Based Compositing for Variable Exposure Photography}},

author = {
Raman, Shanmuganathan
 and 
Chaudhuri, Subhasis
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091034}

}
@inproceedings{
10.2312:egs.20091035,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Depth of Field in Plenoptic Cameras}},

author = {
Georgiev, Todor
 and 
Lumsdaine, Andrew
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091035}

}
@inproceedings{
10.2312:egs.20091037,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Real-time Vision-based Lateral Drift Correction}},

author = {
Hübner, Thomas
 and 
Pajarola, Renato
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091037}

}
@inproceedings{
10.2312:egs.20091036,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A Gaze-Contingent Display Compensating for Scotomata}},

author = {
Duchowski, Andrew T.
 and 
Eaddy, Tiras D.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091036}

}
@inproceedings{
10.2312:egs.20091038,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Continuous Search and Replace in Vector Graphics}},

author = {
Loviscach, Joern
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091038}

}
@inproceedings{
10.2312:egs.20091039,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Multisampled Antialiasing of Per-pixel Geometry}},

author = {
Schwarz, Michael
 and 
Stamminger, Marc
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091039}

}
@inproceedings{
10.2312:egs.20091041,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Levels of Real-Time Crowd Navigation Behaviour in Urban Environments}},

author = {
Haciomeroglu, Murat
 and 
Laycock, Robert G.
 and 
Day, Andrew M.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091041}

}
@inproceedings{
10.2312:egs.20091040,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A Dynamic Caching System for Rendering an Animated Crowd in Real-Time}},

author = {
Lister, Wayne
 and 
Laycock, Robert G.
 and 
Day, Andrew M.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091040}

}
@inproceedings{
10.2312:egs.20091042,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Does Brief Exposure to a Self-avatar Effect Common Human Behaviors in Immersive Virtual Environments?}},

author = {
Streuber, Stephan
 and 
Rosa, Stephan de la
 and 
Trutoiu, Laura
 and 
Bülthoff, Heinrich H.
 and 
Mohler, Betty J.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091042}

}
@inproceedings{
10.2312:egs.20091043,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Volume Conserving Simulation of Deformable Bodies}},

author = {
Diziol, Raphael
 and 
Bender, Jan
 and 
Bayer, Daniel
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091043}

}
@inproceedings{
10.2312:egs.20091046,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A Cost Metric for Scene-Interior Ray Origins}},

author = {
Fabianowski, Bartosz
 and 
Fowler, Colin
 and 
Dingliana, John
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091046}

}
@inproceedings{
10.2312:egs.20091044,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Video-Realistic Image-based Eye Animation System}},

author = {
Weissenfeld, Axel
 and 
Liu, Kang
 and 
Ostermann, J.
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091044}

}
@inproceedings{
10.2312:egs.20091045,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Procedural City Layout Generation Based on Urban Land Use Models}},

author = {
Groenewegen, Saskia A.
 and 
Smelik, Ruben M.
 and 
Kraker, Klaas Jan de
 and 
Bidarra, Rafael
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091045}

}
@inproceedings{
10.2312:egs.20091047,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Fast Approximation of Multiple Scattering in Inhomogeneous Participating Media}},

author = {
Szirmay-Kalos, László
 and 
Liktor, Gábor
 and 
Umenhoffer, Tamás
 and 
Tóth, Balázs
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091047}

}
@inproceedings{
10.2312:egs.20091048,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Real-time Volumetric Lighting in Participating Media}},

author = {
Toth, Balazs
 and 
Umenhoffer, Tamas
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091048}

}
@inproceedings{
10.2312:egs.20091050,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A Precalculated Point Set for Caching Shading Information}},

author = {
Bikker, Jacco
 and 
Reijerse, Roel
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091050}

}
@inproceedings{
10.2312:egs.20091051,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Importance Sampling with Floyd-Steinberg Halftoning}},

author = {
Szirmay-Kalos, László
 and 
Szécsi, László
 and 
Penzov, Anton
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091051}

}
@inproceedings{
10.2312:egs.20091049,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Fast Rendering of Particle-Based Fluid by Utilizing Simulation Data}},

author = {
Yasuda, Ren
 and 
Harada, Takahiro
 and 
Kawaguchi, Yoichiro
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091049}

}
@inproceedings{
10.2312:egs.20091052,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Noise Robust Surface Reconstruction by Combining PU and Graph-cut}},

author = {
Nagai, Yukie
 and 
Ohtake, Yutaka
 and 
Suzuki, Hiromasa
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091052}

}
@inproceedings{
10.2312:egs.20091053,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A new Projection Method for Point Set Surfaces}},

author = {
Kalbe, Thomas
 and 
Fuhrmann, Simon
 and 
Uhrig, Stefan
 and 
Zeilfelder, Frank
 and 
Kuijper, Arjan
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091053}

}
@inproceedings{
10.2312:egs.20091054,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Dent Removal: Geodesic Curve-Based Mesh Fairing}},

author = {
Pinskiy, Dmitriy
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091054}

}
@inproceedings{
10.2312:egs.20091056,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Tile-based Image Forces for Active Contours on GPU}},

author = {
Kienel, Enrico
 and 
Brunnett, Guido
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091056}

}
@inproceedings{
10.2312:egs.20091055,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
A Real-time Interactive Tool for Image Cutout}},

author = {
Liu, Chen
 and 
Li, Fengxia
 and 
Zhang, Yan
 and 
Zhan, Shouyi
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091055}

}
@inproceedings{
10.2312:egs.20091057,

booktitle = {
Eurographics 2009 - Short Papers},

editor = {
P. Alliez and M. Magnor
},
title = {{
Improving Interactive Image Segmentation via Appearance Propagation}},

author = {
Pan, Wei
},
year = {
2009},

publisher = {
The Eurographics Association},


DOI = {
10.2312/egs.20091057}

}

Browse

Recent Submissions

Now showing 1 - 25 of 25
  • Thumbnail Image
    Item
    Preface and Table of Contents
    (The Eurographics Association, 2009) Alliez, P.; Magnor, M.; P. Alliez and M. Magnor
    Preface and Table of Contents
  • Thumbnail Image
    Item
    Bilateral Filter Based Compositing for Variable Exposure Photography
    (The Eurographics Association, 2009) Raman, Shanmuganathan; Chaudhuri, Subhasis; P. Alliez and M. Magnor
    Compositing a scene from multiple images is of considerable interest to graphics professionals. Typical compositing techniques involve estimation or explicit preparation of matte by an artist. In this article, we address the problem of automatic compositing of a scene from images obtained through variable exposure photography. We consider the High Dynamic Range Imaging (HDRI) problem and review some of the existing approaches for directly generating a Low Dynamic Range (LDR) image from multi-exposure images. We propose a computationally efficient method of scene compositing using edge-preserving filters such as bilateral filters. The key challenge is to composite the multi-exposure images in such a way so as to preserve details in both brightly and poorly illuminated regions of the scene within the limited dynamic range.
  • Thumbnail Image
    Item
    Depth of Field in Plenoptic Cameras
    (The Eurographics Association, 2009) Georgiev, Todor; Lumsdaine, Andrew; P. Alliez and M. Magnor
    Certain new algorithms used by plenoptic cameras require focused microlens images. The range of applicability of these algorithms therefore depends on the depth of field of the relay system comprising the plenoptic camera. We analyze the relationships and tradeoffs between camera parameters and depth of field and characterize conditions for optimal refocusing, stereo, and 3D imaging.
  • Thumbnail Image
    Item
    Real-time Vision-based Lateral Drift Correction
    (The Eurographics Association, 2009) Hübner, Thomas; Pajarola, Renato; P. Alliez and M. Magnor
    A major drawback in many robotics projects is the dependance on a specific environment and the otherwise uncertain behavior of the hardware. Simple navigation tasks like driving in a straight line can lead to a strong lateral drift over time in an unknown environment. In this paper we propose a fast and simple solution for the lateral drift problem for vision guided robots by real-time scene analysis. Without an environment-specific calibration of the robot s drive system, we balance the differential drive speed on the fly. Therefore, a feature detector is used on consecutive images. Detected feature points determine the focus of expansion (FOE) that is used for locating and correcting the robot s lateral drift. Results are presented for an unmodified real-world indoor environment that demonstrate that our method is able to correct most lateral drift, solely based on real-time vision processing.
  • Thumbnail Image
    Item
    A Gaze-Contingent Display Compensating for Scotomata
    (The Eurographics Association, 2009) Duchowski, Andrew T.; Eaddy, Tiras D.; P. Alliez and M. Magnor
    A Gaze-Contingent Display (GCD) is developed in GLSL to compensate for scotomata (loss of retinal visual acuity) such as brought on by Age-related Macular Degeneration (AMD). The compensatory GCD introduces a magnification ring slaved to the viewer s gaze point.
  • Thumbnail Image
    Item
    Continuous Search and Replace in Vector Graphics
    (The Eurographics Association, 2009) Loviscach, Joern; P. Alliez and M. Magnor
    Many types of vector graphics comprise large numbers of almost identical partial shapes such as serifs in typeface design, ornaments in illustrations, and stylistic elements in icon design. As of today, later design changes of such shapes require the user to edit every instance on its own. Standard features of vector graphics software help with the automated replacement of stand-alone graphical objects, but do not cover partial shapes. Hence, a geometric search & replace function is needed, which is exacerbated by the circumstance that the repeated shapes construction from curve segments tends to vary from instance to instance, which requires a continuous approach that does not rely on a fixed division of a path into segments. This paper presents a geometric search and replace function that addresses these issues, possesses adjustable tolerance against orientation and size changes between the search pattern shape and the retrieved shapes, and is integrated with a standard vector graphics program.
  • Thumbnail Image
    Item
    Multisampled Antialiasing of Per-pixel Geometry
    (The Eurographics Association, 2009) Schwarz, Michael; Stamminger, Marc; P. Alliez and M. Magnor
    Many algorithms exist which generate per-pixel geometry by selectively discarding fragments generated for a simple bounding geometry. On the other hand, multisampling support has become ubiquitous and is almost free in current graphics hardware. In this paper we leverage the ability of setting a pixel s coverage mask in the pixel shader to make seemingly inherently pixel-based per-pixel geometry approaches compatible with multisampled antialiasing. We consider both the rendering of curve regions as well as displacement mapping with antialiased outer and inner silhouettes.
  • Thumbnail Image
    Item
    Levels of Real-Time Crowd Navigation Behaviour in Urban Environments
    (The Eurographics Association, 2009) Haciomeroglu, Murat; Laycock, Robert G.; Day, Andrew M.; P. Alliez and M. Magnor
    Continuously increasing interest in real-time crowd simulations motivates researchers from multiple disciplines to investigate more realistic and efficient simulations. Often real-time crowd simulation systems are developed to enhance a user s experience. Therefore, in these applications, most of the computer processing power assigned to the crowd simulation should be given to the agents that will clearly gain a user's attention. This paper investigates methods to improve the computational efficiency of the simulation while not effecting the user s experience. For this reason six dynamically sized areas are defined according to the camera's position and direction. Three types of motion algorithms with different complexities are defined to be used in the different simulation areas. The proposed technique is used to simulate 10000 pedestrians in a 4km2 urban environment and is shown to offer more than 10 times improvement in computational performance.
  • Thumbnail Image
    Item
    A Dynamic Caching System for Rendering an Animated Crowd in Real-Time
    (The Eurographics Association, 2009) Lister, Wayne; Laycock, Robert G.; Day, Andrew M.; P. Alliez and M. Magnor
    We present a method to accelerate the rendering of large crowds of animated characters. Recent trends have seen matrix-palette skinning become the prevalent approach due to its low memory overhead and fully dynamic geometry. However, the performance of skeletal animation remains modest in comparison to static rendering since neither temporal nor intra-frame coherency can be exploited. We cast crowd rendering as a memory-management problem and allocate a small geometry cache on the GPU within which animated characters can be stored. This serves to augment matrix-palette skinning with baked geometry and allows animation frames to be re-used by multi-pass rendering, between multiple agents and across multiple frames. Our method builds its cache dynamically and adapts to the current simulation state through use of the page-replacement algorithms traditionally employed by virtual-memory systems. In many cases this negates the need for skinning altogether and enables thousands of characters to be rendered in real-time, each independently animated and without loss of fidelity.
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    Does Brief Exposure to a Self-avatar Effect Common Human Behaviors in Immersive Virtual Environments?
    (The Eurographics Association, 2009) Streuber, Stephan; Rosa, Stephan de la; Trutoiu, Laura; Bülthoff, Heinrich H.; Mohler, Betty J.; P. Alliez and M. Magnor
    A plausible assumption is that self-avatars increase the realism of immersive virtual environments (VEs), because self-avatars provide the user with a visual representation of his/her own body. Consequently having a self-avatar might lead to more realistic human behavior in VEs. To test this hypothesis we compared human behavior in VE with and without providing knowledge about a self-avatar with real human behavior in real-space. This comparison was made for three tasks: a locomotion task (moving through the content of the VE), an object interaction task (interacting with the content of the VE), and a social interaction task (interacting with other social entities within the VE). Surprisingly, we did not find effects of a self-avatar exposure on any of these tasks. However, participant s VE and real world behavior differed significantly. These results challenge the claim that knowledge about the self-avatar substantially influences natural human behavior in immersive VEs.
  • Thumbnail Image
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    Volume Conserving Simulation of Deformable Bodies
    (The Eurographics Association, 2009) Diziol, Raphael; Bender, Jan; Bayer, Daniel; P. Alliez and M. Magnor
    We present a new method for simulating volume conserving deformable bodies using an impulse-based approach. In order to simulate a deformable body a tetrahedral model is generated from an arbitrary triangle mesh. All resulting tetrahedrons are assigned to volume constraints which ensure the conservation of the total volume. For the simulation of such a constraint impulses are computed and applied to the particles of the assigned tetrahedrons. The algorithm is easy to implement and ensures exact volume conservation in each simulation step.
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    A Cost Metric for Scene-Interior Ray Origins
    (The Eurographics Association, 2009) Fabianowski, Bartosz; Fowler, Colin; Dingliana, John; P. Alliez and M. Magnor
    Acceleration structures reducing the number of intersection tests are crucial for high ray tracing performance. The best acceleration structures are currently obtained using the surface area heuristic (SAH) which greedily optimizes a cost metric based on a series of heuristic assumptions about the rays. Noting that rays in many cases originate within the scene's bounding box, we assume a uniform distribution of their origins throughout the scene and derive alternative cost metrics. Our experimental results show that at a slight increase in acceleration structure build time, an improvement in ray tracing speed over the SAH is achieved for most scenes. A more accurate metric based on our assumptions yields even more reliable speed-ups at the cost of higher construction time. We conclude that making more realistic assumptions than the SAH is a promising route for better ray tracing acceleration.
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    Video-Realistic Image-based Eye Animation System
    (The Eurographics Association, 2009) Weissenfeld, Axel; Liu, Kang; Ostermann, J.; P. Alliez and M. Magnor
    In this work we elaborate on a novel image-based system for creating video-realistic eye animations to arbitrary spoken output. These animations are useful to give a face to multimedia applications such as virtual operators in dialog systems. Our eye animation system consists of two parts: eye control unit and rendering engine. The designed eye control unit is based on the statistical analysis of recorded human subjects. We design a new model, which fully automatically couples eye blinks and movements with phonetic as well as prosodic information extracted from spoken language. Subjective tests showed that participants are not able to distinguish between real eye motions and our animations, which has not been achieved before.
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    Procedural City Layout Generation Based on Urban Land Use Models
    (The Eurographics Association, 2009) Groenewegen, Saskia A.; Smelik, Ruben M.; Kraker, Klaas Jan de; Bidarra, Rafael; P. Alliez and M. Magnor
    Abstract Training and simulation applications in virtual worlds require significant amounts of urban environments. Procedural generation is an efficient way to create such models. Existing approaches for procedural modelling of cities aim at facilitating the work of urban planners and artists, but either require expert knowledge or external input data to generate results that resemble real-life cities, or they have long computation times, and thus are unsuitable for non-experts such as training instructors. We propose a method that procedurally creates layouts of structurally plausible cities from high-level, intuitive user input such as city size, location and historic background. The resulting layouts consist of different kinds of city districts which are arranged using constraints derived from established models of urban land use. Our approach avoids the need for external expert engagement in the creation process, and allows for the generation of large city layouts in seconds, making it significantly faster than comparable agent-based software and thus supporting the needs of non-expert creators of virtual cities for many applications.
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    Fast Approximation of Multiple Scattering in Inhomogeneous Participating Media
    (The Eurographics Association, 2009) Szirmay-Kalos, László; Liktor, Gábor; Umenhoffer, Tamás; Tóth, Balázs; P. Alliez and M. Magnor
    This paper presents a fast approximation for the solution of the radiative transfer equation in inhomogeneous participating media. This scheme traces rays from the point light creating spherical wavefronts. While we march on a particular ray, we assume that other rays find similar material properties, which allows the solution of the diffusion equation for this ray. The proposed approximation of the scattered component can be computed in parallel with obtaining the direct term at practically no additional cost. The approximation may be used for direct visualization, an initial guess for an iterative solution, or for the main part of a Monte Carlo solution.
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    Real-time Volumetric Lighting in Participating Media
    (The Eurographics Association, 2009) Toth, Balazs; Umenhoffer, Tamas; P. Alliez and M. Magnor
    Simulating light scattering in participating media, such as dust, fog or smoke, can greatly improve the overall realism of the images. This volumetric effect has been well studied in the context of off-line rendering but is still challenging for interactive applications. In this paper we present a GPU-based algorithm to compute volumetric light-shafts generated by single scattering in participating media. The proposed method uses shadow maps to account for shadowing and interleaved sampling to maintain high frame rates without sacrificing image quality.
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    A Precalculated Point Set for Caching Shading Information
    (The Eurographics Association, 2009) Bikker, Jacco; Reijerse, Roel; P. Alliez and M. Magnor
    In this short paper, we present a caching scheme for low-frequent shading information. The scheme consists of a precalculated, carefully constructed sparse set of points, the density of which adapts to local shading requirements, which we estimate by calculating the ambient occlusion. This fixed set of points is then used to store shading information. This shading information is calculated once, or updated prior to rendering each frame. Finally, during rendering, the shading information stored in the point set is used to estimate shading for any point in the scene using interpolation. We apply this scheme to render soft shadows and indirect lighting in a real-time ray traced game environment.
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    Importance Sampling with Floyd-Steinberg Halftoning
    (The Eurographics Association, 2009) Szirmay-Kalos, László; Szécsi, László; Penzov, Anton; P. Alliez and M. Magnor
    This paper proposes a deterministic importance sampling algorithm for complex integrands. The idea is based on the recognition that halftoning algorithms are equivalent to importance sampling if the gray-scale image and a resulting white pixel are considered as the target importance function and the sampling position, respectively. We adopt the Floyd-Steinberg halftoning algorithm, extend it to higher dimensions, and rephrase it as a sampling method. As the Floyd-Steinberg halftoning places a sample also considering where other samples are located, our sampling algorithm distributes samples in a stratified way. In order to demonstrate the power of the method, we present an environment mapping application where the sampling mimics the product of the cosine weighted BRDF, environment radiance, and the environment visibility.
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    Fast Rendering of Particle-Based Fluid by Utilizing Simulation Data
    (The Eurographics Association, 2009) Yasuda, Ren; Harada, Takahiro; Kawaguchi, Yoichiro; P. Alliez and M. Magnor
    This paper presents a novel algorithm for efficiently visualizing of particle-based fluid simulation with multiple refractions, especially smoothed particle hydrodynamics(SPH), using data and result of simulation itself. In general, particle-based fluid simulation and visualization are processed completely separated. The novelty of our method lives in combination of these two processes to avoid extra processes in visualization, and to mitigate computing cost of visualization.
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    Noise Robust Surface Reconstruction by Combining PU and Graph-cut
    (The Eurographics Association, 2009) Nagai, Yukie; Ohtake, Yutaka; Suzuki, Hiromasa; P. Alliez and M. Magnor
    We present a novel method of reconstructing surfaces from 3D scattered points by combining Partition of Unity (PU) and a Graph-cut approach. PU is a local approximation technique, meaning that the surfaces obtained have high accuracy but are sensitive to noise. Graph-cut, on the other hand, is a global algorithm that is robust to noise but produces low-accuracy results because it is a discrete binary operation. Our algorithm combines these two methods to achieve robust, high accuracy surface reconstruction. First, a PU implicit function is constructed by covering a space containing a point cloud with spherical supports of linear polynomials. Graph-cut is then performed to separate the covered domain into inside and outside areas of the object to be reconstructed. Finally, we extract the zero-level of PU using the marching tetrahedra approach.
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    A new Projection Method for Point Set Surfaces
    (The Eurographics Association, 2009) Kalbe, Thomas; Fuhrmann, Simon; Uhrig, Stefan; Zeilfelder, Frank; Kuijper, Arjan; P. Alliez and M. Magnor
    A successful approach in triangulating point set surfaces is to apply operations, like a projection operator for advancing front algorithms, directly to Moving-Least Squares (MLS) surfaces. The MLS method naturally handles noisy input data and is especially useful for point clouds derived from real-world solids. Unfortunately, MLS is computationally extensive and complex. We present a novel projection method that does not require solving a nonlinear optimization problem as MLS does. We create a polynomial approximation of the surface similar to MLS but our method adapts the degree of the polynomial with respect to the points to be approximated. The approximated points are iteratively collected compromising connectivity information. We enhance the orientation of the local coordinate system to further improve the method. The results confirm that our method is more robust and also accelerates triangulation due to a preprocessing step that needs to be done only once per data set.
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    Dent Removal: Geodesic Curve-Based Mesh Fairing
    (The Eurographics Association, 2009) Pinskiy, Dmitriy; P. Alliez and M. Magnor
    This paper presents a novel mesh fairing method to remove unwanted geometric artifacts such as dents. The key element of the proposed method is our unique algorithm for the assignment of weights in the discrete Laplacian. Our weights reflect the orientation of the first ring of vertices around a given vertex with respect to the whole dented region, rather than the ring's local geometry (e.g. Gauss or mean curvature flow that needs to be reestimated per each iteration). To establish the dent region s global behavior, we perform principal curvature analysis to determine representative geodesic curves for the surface. Our method is efficient as it only needs to compute the geodesic curves once, and then it uses them to guide subsequent iterations of anisotropic relaxation.
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    Tile-based Image Forces for Active Contours on GPU
    (The Eurographics Association, 2009) Kienel, Enrico; Brunnett, Guido; P. Alliez and M. Magnor
    Active contours have been proven to be powerful semiautomatic image segmentation tools. We present an adaptive image force computation scheme in order to minimize both computational and memory requirements. Hence, we are able to perform a fast semiautomatic contour detection in huge images. We present an efficient implementation of this approach on the basis of general purpose GPU processing providing a visual continuous active contour deformation.
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    A Real-time Interactive Tool for Image Cutout
    (The Eurographics Association, 2009) Liu, Chen; Li, Fengxia; Zhang, Yan; Zhan, Shouyi; P. Alliez and M. Magnor
    We present an interactive tool for extracting foreground objects from image in real-time. As seen from the object boundary, the segmentation is to split pixel-pairs right on the boundary. The system utilizes the user input while the user roughly paints the stroke along the object boundary. Either side of the stroke is assumed to lie in foreground or background, and the mouse trace is supposed to coarsely indicate the object contour. We use the appearance, gradient and contour information to formulate the segmentation problem to an energy minimization problem, which is solved by graph cut. The appearance model is built via local sampling, since it often provides more discriminative model in local areas than that from global sampling. In addition, our system can dynamically adjust the stroke and the optimization region for which segmentation needs to be computed. The optimization region is much smaller than the whole image. This greatly reduces the computational complexity in each iteration and also gives the system the ability of incrementally segmenting. Experiments show the effectiveness of our methods in improving the segmentation performance.
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    Improving Interactive Image Segmentation via Appearance Propagation
    (The Eurographics Association, 2009) Pan, Wei; P. Alliez and M. Magnor
    We present Propagate-and-Graphcut (PG), a system that improves interactive image segmentation by leveraging the appearance propagation research. Users efforts are minimized, and inaccurate inputs are handled. We show experimentally that PG is capable of handling complex scenario settings and outperforms previous approaches.We suggest that PG could serve as an alternative to other general interactive image segmentation methods under most circumstances.