@inproceedings{:10.2312/egs.20021001,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Reverse Diffusion for Smooth Buildup of Progressivly Transmitted Geometry}},

author = {Buelow, Thomas
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021001}

}

@inproceedings{:10.2312/egs.20021000,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Measuring and Rendering Art Paintings Using an RGB Camera}},

author = {Tominaga, Shoji and 
Tanaka, Norihiro
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021000}

}

@inproceedings{:10.2312/egs.20021004,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Normal Enhancement for Interactive Non-photorealistic Rendering}},

author = {Cignoni, Paolo and 
Scopigno, Roberto and 
Tarini, Marco
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021004}

}

@inproceedings{:10.2312/egs.20021003,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Adaptive Compression of Human Animation Data}},

author = {Ahmed, Amr Adel Hassan and 
Hilton, Adrian and 
Mokhtarian, Farzin
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021003}

}

@inproceedings{:10.2312/egs.20021002,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Frame-Coherent Stippling}},

author = {Meruvia Pastor, Oscar E. and 
Strothotte, Thomas
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021002}

}

@inproceedings{:10.2312/egs.20021007,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{From Textual Chats to Interest Groups in 3D Virtual Space}},

author = {Masa, Michal and 
Zara, Jiri
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021007}

}

@inproceedings{:10.2312/egs.20021006,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Function-defined shape node for VRML}},

author = {Lai, Feng Min and 
Sourin, Alexei
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021006}

}

@inproceedings{:10.2312/egs.20021005,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{View Interpolation for Dynamic Scenes}},

author = {Xiao, Jiangjian and 
Rao, Cen and 
Shah, Mubarak
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021005}

}

@inproceedings{:10.2312/egs.20021015,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Flexible bump map capture from video}},

author = {Paterson, James Alexander and 
Fitzgibbon, Andrew W.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021015}

}

@inproceedings{:10.2312/egs.20021014,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{SAVANT: A new efficient approach to generating the visual hull}},

author = {Lyons, Alex and 
Kotcheff, Aaron
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021014}

}

@inproceedings{:10.2312/egs.20021008,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Real-time 3D Deformations by Means of Compactly Supported Radial Basis Functions}},

author = {Kojekine, Nikita and 
Savchenko, Vladimir and 
Senin, Mikhail and 
Hagiwara, Ichiro
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021008}

}

@inproceedings{:10.2312/egs.20021017,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Rendering Artistic Line Drawings Using Off-the-Shelf 3-D Software}},

author = {Loviscach, Jörn
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021017}

}

@inproceedings{:10.2312/egs.20021011,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Adaptive Tessellation for Trimmed NURBS Surface}},

author = {YingLiang, Ma and 
Hewitt, Terry
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021011}

}

@inproceedings{:10.2312/egs.20021009,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Texture Mapping on Doo-Sabin Subdivision Surfaces Using Multiple Images}},

author = {Huang, Zhiyong and 
Neo, Chee Seng
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021009}

}

@inproceedings{:10.2312/egs.20021016,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Automated Enhancement of 3D Models}},

author = {Torres-Mendez, L.A. and 
Dudek, G.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021016}

}

@inproceedings{:10.2312/egs.20021010,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Tree balancing for mesh simplification}},

author = {Grabner, Markus
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021010}

}

@inproceedings{:10.2312/egs.20021013,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Texture Minification using Quad-trees and Fipmaps}},

author = {Bornik, Alexander and 
Ferko, Andrej
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021013}

}

@inproceedings{:10.2312/egs.20021012,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Texturing Calibrated Head Model from Images}},

author = {Lempitsky, Victor and 
Ivanov, Denis and 
Kuzmin, Yevgeniy
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021012}

}

@inproceedings{:10.2312/egs.20021023,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Knowledge-Based Representation of Cinematic Expression and its Application to Animation}},

author = {Friedman, Doron and 
Feldman, Yishai
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021023}

}

@inproceedings{:10.2312/egs.20021021,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Feature interference in free form template matching}},

author = {Song, Y. and 
Vergeest, J. S. M. and 
Horvath, I.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021021}

}

@inproceedings{:10.2312/egs.20021022,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Modeling Visual Attention in VR: Measuring the Accuracy of Predicted Scanpaths}},

author = {Duchowski, Andrew and 
Marmitt, Gerd
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021022}

}

@inproceedings{:10.2312/egs.20021026,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Multi-dimensional and Multi-scale Visualizer of Large XML Documents}},

author = {Jacquemin, Christian and 
Jardino, Michele
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021026}

}

@inproceedings{:10.2312/egs.20021025,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Interactive Polygonisation for Function-based Modelling}},

author = {Sourin, Alexei and 
Levinski, Konstantin
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021025}

}

@inproceedings{:10.2312/egs.20021018,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Image Editing with Intelligent Paint}},

author = {Reese, Jack and 
Barrett, William
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021018}

}

@inproceedings{:10.2312/egs.20021019,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Interpolating 2D Shape Hierarchically}},

author = {Johan, Henry and 
Nishita, Tomoyuki
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021019}

}

@inproceedings{:10.2312/egs.20021024,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Improved Bump Mapping by using Quadratic Vector Interpolation}},

author = {Hast, Hans Anders and 
Barrera, Tony and 
Bengtsson, Ewert
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021024}

}

@inproceedings{:10.2312/egs.20021027,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Automatic Data Acquisition and Visualization for Usability Evaluation of Virtual Reality Systems}},

author = {Holm, Roland and 
Priglinger, Markus and 
Stauder, Erwin and 
Volkert, J. and 
Wagner, R.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021027}

}

@inproceedings{:10.2312/egs.20021020,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Rendering of Japanese Artcraft}},

author = {Durikovic, Roman and 
Kolchin, Kostantin and 
Ershov, Sergey
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021020}

}

@inproceedings{:10.2312/egs.20021028,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Fast Volume Carving}},

author = {Pyo, Soon Hyoung and 
Shin, Yeong Gil
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021028}

}

@inproceedings{:10.2312/egs.20021030,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Real-Time Animated Grass}},

author = {Bakay, Brook and 
Lalonde, Paul and 
Heidrich,  Wolfgang
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021030}

}

@inproceedings{:10.2312/egs.20021032,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{A Convolution-Based Algorithm for Animated Water Waves}},

author = {Loviscach, Jörn
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021032}

}

@inproceedings{:10.2312/egs.20021031,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Improved Integration for Cloth Simulation}},

author = {Parks, David L. and 
Forsyth, David A.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021031}

}

@inproceedings{:10.2312/egs.20021034,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Geometric Simplification of Foliage}},

author = {Remolar, Inmaculada and 
Chover, Miguel and 
Belmonte, Oscar and 
Ribelles, Jose and 
Rebollo, Cristina
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021034}

}

@inproceedings{:10.2312/egs.20021033,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Mesh Decimation for Displacement Mapping}},

author = {Collins, Gordon and 
Hilton, Adrian
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021033}

}

@inproceedings{:10.2312/egs.20021029,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Digital Watermarking for Volumetric Datasets}},

author = {Dimitrov, Leonid I. and 
Sramek, Milos
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021029}

}

@inproceedings{:10.2312/egs.20021040,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Distance fields applied to character animation}},

author = {Rudomin, Isaac and 
Castillo, J.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021040}

}

@inproceedings{:10.2312/egs.20021037,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Concise Tour to the Virtual Old Prague}},

author = {Zara, Jiri
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021037}

}

@inproceedings{:10.2312/egs.20021041,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Extraction of Critical Points and Nets Based on Discrete Gradient Vector Field}},

author = {De Floriani, Leila and 
Mesmoudi, Mohammed Mostefa and 
Danovaro, Emanuele
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021041}

}

@inproceedings{:10.2312/egs.20021038,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Dynamic Motion Models}},

author = {Grünvogel, Stefan Michael and 
Lange, Thorsten and 
Piesk, Jens
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021038}

}

@inproceedings{:10.2312/egs.20021039,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Dynamics-Based Motion Synthesis by Simple Learning Control}},

author = {Kiriazov, Petko
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021039}

}

@inproceedings{:10.2312/egs.20021035,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Simulation of Cumuliform Clouds Based on Computational Fluid Dynamics}},

author = {Miyazaki, Ryo and 
Dobashi, Yoshinori and 
Nishita, Tomoyuki
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021035}

}

@inproceedings{:10.2312/egs.20021036,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{A Method for Creating Mosaic Images Using Voronoi Diagrams}},

author = {Dobashi, Yoshinori and 
Haga, Toshiyuki and 
Johan, Henry and 
Nishita, Tomoyuki
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021036}

}

@inproceedings{:10.2312/egs.20021044,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{The Voronoi-Quadtree: construction and visualization}},

author = {Coll, Narcís and 
Boada, Imma and 
Sellares, J.A.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021044}

}

@inproceedings{:10.2312/egs.20021047,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Using pre-integrated Transfer Functions in an Interactive Software System for Volume}},

author = {Knittel, Guenter
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021047}

}

@inproceedings{:10.2312/egs.20021045,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{An Image-Based Radiosity Representation}},

author = {Mertens, Tom and 
Van Reeth, Frank
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021045}

}

@inproceedings{:10.2312/egs.20021042,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Visibility Preprocessing Using Spherical Sampling of Polygonal Patches}},

author = {Meruvia Pastor, Oscar E.
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021042}

}

@inproceedings{:10.2312/egs.20021043,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Dependent Tests Driven Filtering in Monte-Carlo Global Illumination}},

author = {Csonka, Ferenc and 
Szirmay-Kalos, Laszlo and 
Kelemen, Csaba and 
Antal, György
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021043}

}

@inproceedings{:10.2312/egs.20021046,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{On the Integration of Synthetic Objects with Real-World Scenes}},

author = {Abad, Francisco and 
Camahort, Emilio and 
Vivó, Roberto
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021046}

}

@inproceedings{:10.2312/egs.20021049,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Information-Theoretic Oracle Based on Kernel Smoothness for Hierarchical Radiosity}},

author = {Feixas, Miquel and 
Rigau, Jaume and 
Bekaert, Philippe and 
Sbert, Mateu
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021049}

}

@inproceedings{:10.2312/egs.20021048,

booktitle = {Eurographics 2002 - Short Presentations},

editor = {
title = {{Hardware-Assisted Relief Texture Mapping}},

author = {Fujita, Masahiro and 
Kanai, Takashi
},
year = {2002},

publisher = {Eurographics Association},

ISSN = {1017-4656},

DOI = {/10.2312/egs.20021048}

}

Browse

Now showing 1 - 50 of 50

Reverse Diffusion for Smooth Buildup of Progressivly Transmitted Geometry
(Eurographics Association, 2002) Buelow, Thomas
In this paper we consider 3D object surfaces which can be represented as scalar functions defined on the sphere. These objects can be modeled as series of spherical harmonic functions. A simple progressive transmission scheme could be implemented which transmits the expansion coefficients one by one and thus implements a coarse to fine reconstruction. The buildup of the object according to this scheme is not completely smooth: Wavy patterns appear which disappear in subsequent stages and are replaced by finer spurious patterns and so on. We propose a remedy for this behavior which is based on the simulation of a reversed diffusion process on the sphere.
Measuring and Rendering Art Paintings Using an RGB Camera
(Eurographics Association, 2002) Tominaga, Shoji; Tanaka, Norihiro
A method is proposed for measuring and rendering of art paints by using the simple system of an RGB camera only. The surface shape of an art painting is considered as a rough plane rather than a three-dimensional curved surface. Because the surface material has the dichromatic reflection property, the spectral reflectance function is estimated from the diffuse reflection component. First, we present an algorithm for estimating surface normal at each pixel point, based on an extended photometric stereo without using a rangefinder. Next, an algorithm is presented for estimating the spectral reflectance function from a set of RGB color values acquired at different illumination directions. Then, the surface reflectance and normal data are used for estimating the light reflection properties. The Torrance-Sparrow model is used for the model fitting and parameter estimation. Finally, an experiment using an oil painting is executed for demonstrating the feasibility of the proposed method.
Normal Enhancement for Interactive Non-photorealistic Rendering
(Eurographics Association, 2002) Cignoni, Paolo; Scopigno, Roberto; Tarini, Marco
We present a simple technique to improve the perception of shape of an object. Bump mapping is well-known in the computer graphics community for providing the impression of small-scale geometrical features (which actually are not there). Here, we propose a similar approach (variation of normals) for the purpose of enhancing perception of the given geometry. Our approach is based on a simple modification of the surface normals in order to enhance the geometric features of the object during the rendering. The enhanced normals produced by this approach can be used in any rendering technique. The technique presented is particularly well suited to improve the rendering of mechanical parts where common cheap shading techniques can often generate shading ambiguities.
Adaptive Compression of Human Animation Data
(Eurographics Association, 2002) Ahmed, Amr Adel Hassan; Hilton, Adrian; Mokhtarian, Farzin
In this paper we introduce an adaptive motion compression technique using the discrete wavelet transform. Based on the analysis of human animation data, and its frequency contents, the wavelet analysis is utilised to achieve motion compression. It has been found that even with high compression ratios (up to 86%), the compressed animation is visually very close to the original animation. This property is potentially useful for many areas of animation such as motion interpolation/blending and networked virtual environments. One of our motivations is that motion blending/interpolation between motion capture samples is one of the successful techniques for synthesis of novel realistic human animation. One of the major concerns of that method is the increase of the database size with the large number of samples required to synthesise a wide range of movements. Previous research has addressed this issue by trying to reduce the number of samples required for interpolation. The approach that we introduce in this paper is to reduce the individual sample’s size using compression. Integration of both these approaches promises to allow a realistic animation with reduced database size. In networked virtual environments and on-line games, compressing the animation data can reduce the transmission load and help in achieving real-time performance and realism with reduced cost.
Frame-Coherent Stippling
(Eurographics Association, 2002) Meruvia Pastor, Oscar E.; Strothotte, Thomas
Stippling is an artistic rendering technique where shading and texture is given by placing points or stipples on the canvas until the desired darkness is achieved. Computer-generated stippling has focused on producing high quality 2D renditions for print media, while stippling of 3D models in animation has received little attention. In this paper we present a technique to produce frame-coherent animations of 3D models using stippling as a rendering style. The problem for which we provide a solution is how to obtain an even distribution of stipples and at the same time ensure frame-to-frame coherence while shading changes over time. In our approach, particles are placed on the surface of the 3D model and adaptively rendered as stipples using OpenGL point primitives and the input model as a canvas. At each frame, the density of particles can be increased if necessary. Selection of particles during rendering takes into account the screen space projection of the edges of a polygon fan that surrounds the particles and the desired tone at the position of the particles. The rendering technique presented here can be applied to arbitrary polygonal meshes and can be extended to include grey scale textures, bump mapping and custom illumination models.
From Textual Chats to Interest Groups in 3D Virtual Space
(Eurographics Association, 2002) Masa, Michal; Zara, Jiri
While the textual chat is a highly popular tool for various kinds of social interactions, its extension to the visual three-dimensional domain remains almost untouched and without practical utilization yet. This paper discusses advantages and disadvantages of spatial virtual environment when used as a platform for connecting people and serving for social and cultural interaction. The differences between textual chat and interest groups in virtual reality are highlighted with the aim to overcome the gap between well-established chat technology and promising but still a bit exotic virtual reality approach. Theoretical analysis is followed by several examples taken from experimental setup.
Function-defined shape node for VRML
(Eurographics Association, 2002) Lai, Feng Min; Sourin, Alexei
This paper describes how the web-based visualisation can be greatly improved using the function-based shape modelling technique. We propose the function-defined VRML shape node, which allows the content creators to describe any complex models with relatively small functions compared to the large-size polygonal mesh based VRML nodes. The design, the implementation details, and the application examples of the proposed node are discussed. The software is available for downloading from the project website.
View Interpolation for Dynamic Scenes
(Eurographics Association, 2002) Xiao, Jiangjian; Rao, Cen; Shah, Mubarak
This paper describes a novel technique for synthesizing a dynamic scene from two images without the use of a 3D model. A scene containing rigid or non-rigid objects, in which each object can move in any orientation or direction, is considered. It is shown that such a scene can be converted into several equivalent static scenes, where each scene only includes one rigid object. Our method can generate a series of continuous and realistic intermediate views from only two reference images without 3D knowledge. The procedure consists of three main steps: segmentation, morphing and postwarping. The key frames are first segmented into several layers. Each layer can be realistically morphed after determining its fundamental matrix. Based on the decomposition of 3D rotation matrix, an optimized and unique postwarping path is automatically determined by the least distortion method and boundary connection constraint. Finally, four experiments, which include morphing of a rotating rigid object in presence of occlusion and morphing of non-rigid objects (human), are demonstrated.
Flexible bump map capture from video
(Eurographics Association, 2002) Paterson, James Alexander; Fitzgibbon, Andrew W.
We extend recent techniques for the automated capture of surface normal maps or bump maps from real-world material samples. In contrast to recent systems, which have required cumbersome laboratory setups with careful calibration, we propose a moving-camera system which requires only one light source, rigidly attached to the camera. We describe a simple but accurate image-based calibration technique which allows the construction of an approximation to the standard photometric stereo setup. We show how to optimally estimate the system geometry during capture, and demonstrate that the accuracy of the new system is sufficient to allow normals to be computed.
SAVANT: A new efficient approach to generating the visual hull
(Eurographics Association, 2002) Lyons, Alex; Kotcheff, Aaron
We present a new approach to generating a boundary representation (a polygonal mesh) of the visual hull from a set of silhouettes of an object taken from known camera positions. The approach uses spatial subdivision to compute the positions of vertices and then traverses the vertices around planar faces to produce a facetted representation of the visual hull. We show that, unlike standard approaches, the method is practical even for a large number of complex silhouettes. It is applicable to any 3D modeling system that uses the “shape-from-silhouette” approach to generating 3D models of objects. The approach can also be extended to efficiently compute polygonal mesh representations of the intersection of a set of arbitrary polyhedral models. This extends its applicability to CAD systems.
Real-time 3D Deformations by Means of Compactly Supported Radial Basis Functions
(Eurographics Association, 2002) Kojekine, Nikita; Savchenko, Vladimir; Senin, Mikhail; Hagiwara, Ichiro
We present an approach to real-time animation of deformable objects. Optimization of algorithms using compactly supported radial basis functions (CSRBF) allows us to generate deformations performed fast enough for such real-time applications as computer games. The algorithm described in detail in this paper uses space mapping technique. Smooth local deformations of animation objects can be defined by only a moderate number of control vectors and locality of deformations can be defined by radius of support. We also present examples of animations and speed benchmarks.
Rendering Artistic Line Drawings Using Off-the-Shelf 3-D Software
(Eurographics Association, 2002) Loviscach, Jörn
Most commercial 3-D software packages used for animated films and still picture production offer merely rudimentary support for non-photorealistic rendering. However, nearly all of these packages possess interfaces which allow the user to add custom shader programs. We present a solution which uses a custom shader combined with post-processing software in order to draw outlines and creases of 3-D scenes in a way which simulates artistic tools like pencils and ink brushes.
Adaptive Tessellation for Trimmed NURBS Surface
(Eurographics Association, 2002) YingLiang, Ma; Hewitt, Terry
We present an adaptive method for tessellating the trimmed NURBS surface in the parametric domain. Given a model space tolerance ε, the algorithm first splits the NURBS surface in both the U and V directions to fit within the bounding box of the outer trimming loop. Then we subdivide the surface into Bézier patches recursively until the control net of the Bézier patch is flat enough and within the tolerance ε. By building up the quadtrees of inner trimming loops, we use the scanline algorithm to remove the patches inside the inner trimming loops. Finally, we close the inner trimming loops with a set of triangles. The resulting tessellation contains both quadrilaterals and triangles.
Texture Mapping on Doo-Sabin Subdivision Surfaces Using Multiple Images
(Eurographics Association, 2002) Huang, Zhiyong; Neo, Chee Seng
We propose a texture mapping method on subdivision surfaces using multiple images and have implemented it on Doo- Sabin scheme. At the beginning, one texture map is specified for each control mesh face respectively. In a subdivision process, a new face of control meshes may fall into a region of multiple texture maps. To correctly texture map on such faces, we need to further split the new faces into multiple parts so that each of them falls into a region of only one texture map. A splitting algorithm is devised. The novelty of our work is on a generalization of the method of DeRose et al. for the treatment of the use of multiple images.
Automated Enhancement of 3D Models
(Eurographics Association, 2002) Torres-Mendez, L.A.; Dudek, G.
The acquisition of a 3D model of a real environment can be accomplished using range sensors. In practice, suitable sensors to densely cover a large environment are often impractical. This paper presents ongoing work on the synthesis of 3D environment models from as little as one intensity image and sparse range data. Our method is based on interpolating the available range data using statistical inferences learned from the available intensity image and from those (sparse) regions where both range and intensity information is available. Since we compute the relationship between extisting range data and the images we start with, we do not need to make any strong assumptions about the kind of surfaces in the world (for example we do not need to assume the world exhibits only diffuse reflectance). Experimental results show the feasibility of our method.
Tree balancing for mesh simplification
(Eurographics Association, 2002) Grabner, Markus
In this paper, a tree balancing technique is presented that reduces the number of hierarchy levels in typical paircontraction based mesh simplification methods. A well-balanced hierarchy is essential for data structures that explicitly represent vertices as the corresponding paths through the simplification hierarchy. The quality of the generated meshes is evaluated by three methods. The deviation between the simplified and the original mesh is measured by the Hausdorff distance. The shape of the individual triangles is evaluated by Guéziec’s compactness value. Finally, a plot showing the shape distribution of all triangles in the mesh is given. The experiments show that tree balancing has no significant impact on triangle quality.
Texture Minification using Quad-trees and Fipmaps
(Eurographics Association, 2002) Bornik, Alexander; Ferko, Andrej
The paper extends the recently published methods for image reconstruction and texture minification using the generalized ripmap method, named fipmap, and quad-trees. Fipmap is based on the technique of partitioned iterated function systems, used in fractal image compression. The quad-tree texture reconstruction algorithm works well for many standard cases. The special cases can be solved using the fipmap minification. The approach was applied for textures from architectural image sequences and the results are very promising.
Texturing Calibrated Head Model from Images
(Eurographics Association, 2002) Lempitsky, Victor; Ivanov, Denis; Kuzmin, Yevgeniy
In this paper we address a well-known problem of producing an animated model of a human head from a pair of orthogonal photographs and present a new technique of generating consistent high-quality texture for a polygonal 3D mesh which represents a personalized 3D head. The described technique is based on a combination of two different approaches to this problem and significantly extends them in order to produce optimal image in terms of minimizing visual artifacts and keeping level of details as high as possible. After a brief introduction to the complete calibration pipeline that we have used, we describe the stages of texture generation procedure, which consists of indexing available photographs with texture coordinates, finding optimal merging lines and balancing visual differences to allow for seamless merging while preserving high-frequency details. The presented technique has been evaluated within head animation software and demonstrated its ability of yielding high-quality textured model from photographs.
Knowledge-Based Representation of Cinematic Expression and its Application to Animation
(Eurographics Association, 2002) Friedman, Doron; Feldman, Yishai
Camera control in virtual environments received growing attention recently, and some of the research turned to cinematography as a source for inspiration. Cinematic knowledge is a highly challenging domain for formalization. We have used a systematic knowledge-based approach for knowledge acquisition and formalized expert knowledge in the form of fine-grained rules. Given a screenplay, the rules interact to suggest a solution by symbolic constraint propagation and truth maintenance. We have implemented a prototype system that accepts screenplays in a formal language and generates editing decisions, based on a cinematic knowledge base. If the system is provided with 3D meshes and animations corresponding to the actions and objects mentioned in the screenplay, the system generates a 3D animation clip for the screenplay, based on its editing decisions. The system can be equipped with cinematic principles from various genres, and shows how complex cinematic phenomena can emerge from the interaction of simple rules.
Feature interference in free form template matching
(Eurographics Association, 2002) Song, Y.; Vergeest, J. S. M.; Horvath, I.
Template matching is a useful method in the reconstruction of free form surfaces. In this paper, matching of free form surfaces with parameterized templates is studied with the emphasis on feature interference. By their definitions in 3- Dimensional space, free form features are introduced, analyzed and parameterized first. An optimization function based on a Hausdorff-like shape distance measuring method is proposed and applied as measuring method between the digitalized model surface and the parameterized feature template. The proposed method not only can fit isolated free form features, but also works when a feature is interfered by other free form features in some specified conditions. A series of numerical experiments have been conducted to demonstrate the proposed methods based on ACIS and Open Inventor. Fitting strategies are proposed as well.
Modeling Visual Attention in VR: Measuring the Accuracy of Predicted Scanpaths
(Eurographics Association, 2002) Duchowski, Andrew; Marmitt, Gerd
Dynamic human vision is an important contributing factor to the design of perceptually-based Virtual Reality. A common strategy relies on either an implicit assumption or explicit measurement of gaze direction. Given the spatial location of foveal vision, computational resources are directed at enhancing the foveated region in realtime. To obtain an explicit gaze measurement, an eye tracker may be used. In the absence of an eye tracker, a computational model of visual attention may be substituted to predict visually salient features. The fidelity of the resultant real-time system hinges on the agreement between predicted and actual regions foveated by the human. The contributions of this paper are the development and evaluation of a novel method for the comparison of human and artificial scanpaths recorded in VR. The novelty of the present approach is the application of previous accuracy measures to scanpath comparison in VR where analysis is complicated by head movements and dynamic imagery. An attentional model previously used for view-dependent enhancement of Virtual Reality is evaluated. Analysis shows that the correlation between human and artificial scanpaths is much lower than expected. Recommendations are made for improvements to the model to foster closer correspondence to human attentional patterns in VR.
Multi-dimensional and Multi-scale Visualizer of Large XML Documents
(Eurographics Association, 2002) Jacquemin, Christian; Jardino, Michele
3D-XV (3-Dimensional XML Visualizer) is an interactive graphical interface for accessing large structured documents. It relies on a geometrical model that combines a sequential organization and a hierarchical structure. In the overview mode, the user can access information through natural language queries. In the browsing mode, the content of the paragraphs is displayed in a moving walkway fashion. The model is compared with previous studies on document visualization for passage retrieval. The merits of interactive 3D manipulation through the intuitively oriented 3D-XV geometrical model are outlined.
Interactive Polygonisation for Function-based Modelling
(Eurographics Association, 2002) Sourin, Alexei; Levinski, Konstantin
This paper addresses interactive function-based shape modelling. Interactive modification of the function model with concurrent visualization of the respective polygonal mesh lets us provide both the interactivity and any required level of detail leading to photo-realistic appearance of the resulting shapes. We have proposed an interactive visualisation method capable of handling local shape modifications with any desired precision. We illustrate the implementation of the proposed visualisation method on the example of the interactive function-based artistic shape modelling.
Image Editing with Intelligent Paint
(Eurographics Association, 2002) Reese, Jack; Barrett, William
Intelligent Paint provides a new tool for interactively selecting image objects or regions of interest, while simultaneously applying filters or effects directly to the selection(s). By coupling adaptive cost-ordered region growing with the high-level visual expertise of the user to indicate which objects are of interest, we are able to accurately select and edit complex, non-homogeneous objects in only a few seconds using simple mouse input gestures. Prior to selection, the image is oversegmented using a watershed (tobogganing) algorithm. Watershed catchment basins are assembled into an hierarchical image partition by grouping basins using the student’s t-distribution. Grouped basins, referred to as TRAPs (Tobogganed Region Accumulation Plateaus), reasonably capture sub-object detail. Object selection is accomplished by user-steered, adaptive, cost-ordered collection of TRAPs. Tinting or application of filters during object selection provides immediate visual feedback as to what is being selected as well as the suitability of the chosen digital effect. Intelligent Paint selection compares favorably with popular commercial tools in terms of efficiency, accuracy and reproducibility with the added benefit of on-the-fly filtering, while raising the granularity of image editing from the pixel to the object-level. Novel tools for object-centered image editing such as Intelligent Eraser and Intelligent Clone tools are also possible with this technique.
Interpolating 2D Shape Hierarchically
(Eurographics Association, 2002) Johan, Henry; Nishita, Tomoyuki
Shape interpolation has been widely used in the field of computer graphics for modeling and for creating visual effects. This paper presents a novel hierarchical method to interpolate between two 2D shapes. A hierarchical representation, which is a hierarchy of triangles, is proposed to represent the interior and the details of each shape. By constructing the compatible hierarchical representations of the two shapes, the intermediate shapes are computed by interpolating the corresponding triangles at the lowest level to the highest level of the representations, From experimental results, the proposed method produces smooth interpolation sequences.
Improved Bump Mapping by using Quadratic Vector Interpolation
(Eurographics Association, 2002) Hast, Hans Anders; Barrera, Tony; Bengtsson, Ewert
Bump mapping is a technique that perturbs normals used in the illumination computation in order to make the surface appear rough or wrinkled. Standard graphics hardware linearly interpolates rotated vectors in the direction to the light source over the polygon. Then, a cube map is used to normalize these vectors. We propose the use of quadratic interpolation instead, which will make the normalization stage unnecessary. The result is faster bump mapping with quality near the quality obtained by using vector interpolation with normalization. Quadratic interpolation is already used for ordinary shading but has to our knowledge not previously been used for bump mapping. The fast setup we use in our new algorithm can also be applied to Phong shading resulting in increased performance. Similarly the same approach can be used for efficiently setting up the linear interpolation.
Automatic Data Acquisition and Visualization for Usability Evaluation of Virtual Reality Systems
(Eurographics Association, 2002) Holm, Roland; Priglinger, Markus; Stauder, Erwin; Volkert, J.; Wagner, R.
Evaluating the usability of a Virtual Reality system is a common practice nowadays. However, gathering and analyzing the necessary data are time-consuming tasks and sometimes involve inconvenient changes to the system. The VR-based safety training system SAVE suffered from this problem. Therefore, independent modules have been developed to acquire and visualize usability relevant data to allow extensive evaluation sessions to be performed efficiently. Interaction and simulation data is acquired automatically and joined with external physiological data to be visualized inside a complete 3D representation of the training scenario. Visualizations can be performed in real-time while acquiring the data during a session, or from recorded data after the session has been completed. Because the visualization is coupled with a VR authoring tool, it is also possible to analyze the usability of a VR scenario and perform changes instantly.
Rendering of Japanese Artcraft
(Eurographics Association, 2002) Durikovic, Roman; Kolchin, Kostantin; Ershov, Sergey
We present several methods for simulation of Japanese lacquer ware, a prominent Far East Asian handicraft art. We consider two most popular kinds of Japanese lacquer ware made by the makie and nashiji techniques. For rendering makie, we propose a method for preparing RGBA textures from digital photos of art items. The alpha channels of these textures control the weight with which color channels are blended with the measured biderectional reflectance distribution function (BRDF) of a metallic finish. Both ray tracing and hardware based rendering are demonstrated. In the latter case, we show how the calculation of a sphere map texture used for BRDF visualization can be accelerated using a special coordinate system for tabulated BRDF. The depth effect manifested by nashiji lacquer is simulated by the explicit modeling of metal platelets immersed in absorptive material.
Fast Volume Carving
(Eurographics Association, 2002) Pyo, Soon Hyoung; Shin, Yeong Gil
In recent years, the volumetric scene representation has been widely used in the fields of computer graphics and computer vision. In computer graphics, the representation is used to visualize and reconstruct 3D internal structures of 2D human-body medical data obtained from Magnetic Resonance Imaging (MRI) or Computed Tomography (CT). On the other hand, the volumetric representation is used to model 3D objects from a sequence of 2D images in computer vision. In both cases, eliminating some unnecessary part of the volumetric data is sometimes needed. For example, we need to remove skin or tissue which hides the target organ of human in volume rendering, or empty region of 3D objects being modeled in image-based modeling. In this paper, we propose a fast carving algorithm which can be applied in volume rendering and image-based modeling. The memory usage is minimized by using 1-bit field of a voxel to represent whether the voxel is carved or not. Our experiments show that we can carve out any part of the 5123 volume data in about a second. The carving speed is not affected by the complexity of objects.
Real-Time Animated Grass
(Eurographics Association, 2002) Bakay, Brook; Lalonde, Paul; Heidrich, Wolfgang
We present a simple method to render fields of grass, animated in the wind, in real-time. The technique employs vertex shaders to render displacement maps with Russian-doll style transparent shells. Animation is achieved by translating the surface according to a local wind vector while preserving the length of the blades of grass. This technique achieves convincing results on current consumer graphics hardware and can be applied to other similar surfaces such as hair and fur.
A Convolution-Based Algorithm for Animated Water Waves
(Eurographics Association, 2002) Loviscach, Jörn
A non-linear partial differential equation solver is too sophisticated for computer graphics applications if they are only used to render effects like circular waves and ship wakes. We present an approach which simulates waves through a convolution algorithm. It handles both gravity waves and capillary waves; the latter are often neglected even though they dominate small-scale behavior. The algorithm can be integrated into a complete solution architecture: First, standard commercial 3-D software is used to prepare an animated scene with objects traveling on a water surface. Based on the movements of these objects, waves are calculated and added as bump and displacement maps to the 3-D model.
Improved Integration for Cloth Simulation
(Eurographics Association, 2002) Parks, David L.; Forsyth, David A.
Most methods of cloth simulation produce animations that do not move very freely; the result often looks like the material is “swimming”. The primary sources of this phenomenon are the non-physical dissipation terms often added to the mechanics to ensure stability in the simulation, and the numerical damping that is implicit in the choice of ODE integration schemes. By disposing of the additional dissipation terms and choosing a new integrator, the generalized-a method, that was designed to safely integrate mechanical systems with extraneous high-frequency signals in their temporal component, we obtain more realistic results often with the about the same amount of computation.
Geometric Simplification of Foliage
(Eurographics Association, 2002) Remolar, Inmaculada; Chover, Miguel; Belmonte, Oscar; Ribelles, Jose; Rebollo, Cristina
One of the most important challenges in real-time rendering of outdoor scenes is the representation of vegetation. This is due to the vast amount of polygons that are used to model vegetable species. The present automatic simplification algorithms produce acceptable results in the trunks and the branches, but not in the foliage of a tree. After simplification with the existing methods, the trees seem to be less leafy. In this paper, a new automatic simplification algorithm for this part of the tree is presented, the Foliage Simplification Algorithm. It diminishes the number of polygons in the crown, while maintaining the appearance. It uses a new method, leaf collapse: two leaves disappear to create a new one. The leaves obtained after collapsing preserve an area similar to that of the collapsed leaves
Mesh Decimation for Displacement Mapping
(Eurographics Association, 2002) Collins, Gordon; Hilton, Adrian
We present a mesh decimation algorithm for triangular meshes. Unlike other decimation algorithms we are not concerned with geometric error but with the existence of a displacement mapping which can map between the original and decimated meshes. We use the implicit function theorem to derive a condition which ensures the existence of a displacement map. The algorithm is applied to some standard scanned models and reduction rates around 99% are seen.
Digital Watermarking for Volumetric Datasets
(Eurographics Association, 2002) Dimitrov, Leonid I.; Sramek, Milos
An idea for digitaly watermarking volumetric datasets (VDS) and preliminary results from a test implementation are presented. It consists of a combination of filtering and rendering operations on volumetric data allowing for identification of the voxels suitable for hiding the watermark and spreading the information in the gradients of the selected voxels. Thus, a secure and robust method for watermarking VDS could be developed which takes into account the specific properties of volumetric data and advantageously utilizes them.
Distance fields applied to character animation
(Eurographics Association, 2002) Rudomin, Isaac; Castillo, J.
A general hybrid geometric-physical method that is useful for animating characters with skin, clothing and a MPEG-4 compatible face is presented. This method uses an approximation to the underlying musculo-skeletal structure of the body and face to generate a distance field, used for collision detection purposes, and skin/clothing consisting of a particle-spring mesh. The results obtained deliver animation with plausible dynamics for fairly detailed models at around 60fps on a PIII computer with Nvidia Gforce2 graphics. The main contribution is to show that similar algorithms can be used for skin, clothing and facial animation, at interactive rates.
Concise Tour to the Virtual Old Prague
(Eurographics Association, 2002) Zara, Jiri
This paper describes a structure and a user interface of the Internet based 3D presentation of existing historical part of city Prague. The application offers a smooth tour to selected regions of the real city, utilizing number of standard and modern technologies including VRML, Java, and PHP. The architecture of the whole virtual model is presented together with several advanced and specific features like dynamic loading und unloading objects or newly proposed LOD for urban scenes. This running web application seems to be currently unique in terms of complexity, functionality, and scaleability for further growth. The paper introduces methodology suitable for immediate creation of arbitrary virtual city according to a real one.
Extraction of Critical Points and Nets Based on Discrete Gradient Vector Field
(Eurographics Association, 2002) De Floriani, Leila; Mesmoudi, Mohammed Mostefa; Danovaro, Emanuele
In this paper we address the problem of representing the topology of discrete scalar fields defined on triangulated domains. To this aim, we use the notion of discrete gradient vector field that we have introduced in [4] to classify the critical points of a scalar field defined over a two-dimensional domain that generalizes the nature of critical points in the differentiable case. Then we sketch an algorithm for extracting a critical net in the discrete case.
Dynamic Motion Models
(Eurographics Association, 2002) Grünvogel, Stefan Michael; Lange, Thorsten; Piesk, Jens
Real-time animation of virtual characters is a demanding task. We propose dynamic motion models which can create the motion of a virtual character in different styles and have the ability to change the animation while it is played. The motions are created by blending and changing given base motions which contain animation data and additional information. The blending and manipulation operations on the animation data build up a motion tree which can be altered dynamically in real-time. This allows to change the animation of a motion model while its animation is played. Motion trees of different motion models are blended together to build a motion tree which represents the complete animation of the character. This tree is constructed and dynamically changed according to user commands.
Dynamics-Based Motion Synthesis by Simple Learning Control
(Eurographics Association, 2002) Kiriazov, Petko
Point-to-point motion of a humanoid agent (or any mobile creature) is considered as a composition of basic movements related to the degrees of freedom. With time/energy performance criteria, such movements can be synthesized by using simple control functions. Natural looking animation can be achieved employing even very simplified dynamics models. Their parameters can be estimated or identified using motion capture data. In case no appropriate dynamic model is available, we propose an efficient procedure of direct motion editing. The captured motion can be re-used in order to animate the original or other characters in a variety of similar motion tasks. The proposed approach for motion synthesis is applied in the case of a six-link biped. Two examples are considered: one for editing captured walking motion and the other of direct motion synthesis for climbing stairs. The proposed methodology is very appropriate for interactive character animation.
Simulation of Cumuliform Clouds Based on Computational Fluid Dynamics
(Eurographics Association, 2002) Miyazaki, Ryo; Dobashi, Yoshinori; Nishita, Tomoyuki
Simulation of natural phenomena is one of the important research fields in computer graphics. In particular, clouds play an important role in creating images of outdoor scenes. Fluid simulation is effective in creating realistic clouds because clouds are the visualization of atmospheric fluid. In this paper, we propose a simulation technique, based on a numerical solution of the partial differential equation of the atmospheric fluid model, for creating animated cumulus and cumulonimbus clouds with features formed by turbulent vortices.
A Method for Creating Mosaic Images Using Voronoi Diagrams
(Eurographics Association, 2002) Dobashi, Yoshinori; Haga, Toshiyuki; Johan, Henry; Nishita, Tomoyuki
This paper proposes a non-photorealistic rendering method that creates an artistic effect called mosaicing. The proposed method converts images provided by the user into the mosaic images. Commercial image editing applications also provide a similar function. However, these applications often trade results for low-cost computing. It is desirable to create high quality images even if the computational cost is increased. We present an automatic method for mosaicing images by using Voronoi diagrams. The Voronoi diagrams are optimized so that the error between the original image and the resulting image is as small as possible. Next, the mosaic image is generated by using the sites and edges of the Voronoi diagram. We use graphics hardware to efficiently generate Voronoi diagrams. Furthermore, we extend the method to mosaic animations from sequences of images.
The Voronoi-Quadtree: construction and visualization
(Eurographics Association, 2002) Coll, Narcís; Boada, Imma; Sellares, J.A.
We define a quadtree-based planar Voronoi diagram codification, the Voronoi-Quadtree, valid for generalized sites (points, line-segments, curve-arc segments, ...) and for different distance functions (Euclidean metrics, convex distance functions, ...).We present an algorithm for constructing, at a prefixed level of detail, the Voronoi-Quadtree associated to a Voronoi diagram determined by a set of sites and a given distance function. A second algorithm that, taking as input a Voronoi-Quadtree, visualizes a polygonal approximation of the boundary of the Voronoi diagram is also described.
Using pre-integrated Transfer Functions in an Interactive Software System for Volume
(Eurographics Association, 2002) Knittel, Guenter
We explore possibilities to implement classification based on pre-integrated transfer functions in a software system for high-speed volume rendering. The major obstacle to remove is the large size of the multi-dimensional look-up tables. For high rendering performance, all parameters must be available in the L1-cache of the CPU, which is usually by far too small to hold the required tables. We discuss a cache-efficient and fast approximate solution and present a comparison to the standard classification method with respect to performance and image quality.
An Image-Based Radiosity Representation
(Eurographics Association, 2002) Mertens, Tom; Van Reeth, Frank
We present a geometry-independent radiosity representation which stems from image-based methodologies. Our image-based representation is inspired by the concept of layered depth images. To construct the radiosity function we render shaded depth images and warp them into the representation. This enables us to alter Keller’s instant radiosity algorithm to a view-independent variant, allowing interactive viewing of complex scenes without relighting every frame. Image warping is done on the host CPU, while graphics hardware is exploited for rendering the images. Our approach differs from the traditional finite element methods since no a priori meshing, nor an explicit form factor evaluation needs to be performed. The geometry independence ensures a reliable rendering time and memory usage, which are more dependent on image resolution rather than scene complexity. It also implies that lighting information is decoupled from scene representation, thereby avoiding the restriction to planar surfaces and issues such as discontinuity meshing.
Visibility Preprocessing Using Spherical Sampling of Polygonal Patches
(Eurographics Association, 2002) Meruvia Pastor, Oscar E.
A technique is presented that permits fast view-reconstruction of individual objects. This method improves a previous approach to solve the problem of approximated view reconstruction by combining clustering of polygons with visibility bitfields to determine visibility for novel viewpoints. The technique consists of three steps: patch creation, spherical sampling, and rendering. In the first stage, the input 3D model is tiled in polygonal patches. In the sampling stage images of the model are taken from several points on the surface of a viewing sphere. Patch-ID bitfields, which are structures that contain visibility information, are computed for each picture. In the rendering stage, a subset of the viewpoints computed for sampling is selected depending on the viewers position on the viewing sphere and the bitfields of the selected viewpoints are used to rebuild the visible parts of the model from the new viewpoint. The overall system presented here makes a very efficient use of memory resources, and involves practically no overhead during rendering while significantly improving frame rate during interaction with large models. Although the technique is not conservative, our results show that the reconstructed views are practically identical to the original views of the model.
Dependent Tests Driven Filtering in Monte-Carlo Global Illumination
(Eurographics Association, 2002) Csonka, Ferenc; Szirmay-Kalos, Laszlo; Kelemen, Csaba; Antal, György
This paper presents a multi-phase algorithm to solve the global illumination problem. In the first phase dependent tests are applied, i.e. the random walks of different pixels are built from the same random numbers. The result of the first phase is used to identify homogeneous pixel groups in the image. The criterion of the formation of such groups is that averaging the color inside these groups should result in less error than handling the pixels independently. The second phase of the algorithm is a conventional random walk method that uses independent random samples in different pixels. The final result is calculated as the average of the results of the dependent tests and the lowpass filtered version of the independent tests. This low-pass filter averages the pixel values inside the homogenous groups. The algorithm takes advantage of the fact that the image can contain larger homogeneous regions that can be calculated from much less number of samples. Thus we can focus on those pixels where significant changes happen.
On the Integration of Synthetic Objects with Real-World Scenes
(Eurographics Association, 2002) Abad, Francisco; Camahort, Emilio; Vivó, Roberto
This paper presents a method for integrating synthetic objects in real-world photographs. We take a set of photographs of a real scene and build a simple image-based model. We use high dynamic range images to build an accurate representation of the lighting in the scene. Then we insert a synthetic object into the model and compute its illumination and shading using the lighting information. Illumination changes produced by the synthetic object are also applied to the background plane in the real-world photograph. We show how easy it is to achieve photorealistic results without specialized hardware. Our approach takes advantage of techniques like automatic camera calibration, high-dynamic range image capture and image-based lighting. We show preliminary results obtained with our application. We also present two improvements that we are currently studying. They are aimed at improving the quality of the resulting images and decreasing the computational resources needed by the process.
Information-Theoretic Oracle Based on Kernel Smoothness for Hierarchical Radiosity
(Eurographics Association, 2002) Feixas, Miquel; Rigau, Jaume; Bekaert, Philippe; Sbert, Mateu
One of the main problems in the radiosity method is how to discretise the surfaces of a scene into mesh elements that allow us to accurately represent illumination. In this paper we present a robust information-theoretic refinement criterion (oracle) based on kernel smoothness for hierarchical radiosity. This oracle improves on previous ones in that at equal cost it gives a better discretisation, approaching the optimal one from an information theory point of view, and also needs less visibility computations for a similar image quality.
Hardware-Assisted Relief Texture Mapping
(Eurographics Association, 2002) Fujita, Masahiro; Kanai, Takashi
Image-Based Rendering by Warping (IBRW) creates three-dimensional scene by deforming several 2D images with depth information. Image-based rendering has an advantage compared to traditional polygon rendering that the rendering time is still constant even if a scene becomes complex. Relief texture mapping decomposes IBRWinto a very simple 1D image operation and a traditional texture mapping, which allows more effective computations. In this paper, we try to apply some hi-quality shading effects such as reflection mapping for relief texture mapping. Their effects can be realized by per-pixel shading technology of today’s graphics hardware. Our method for relief texture mapping allows fast and almost the same shading as well as traditional polygon rendering.

BibTeX (Short Presentations)

Browse

Recent Submissions

Results Per Page

Sort Options