EG2002

Permanent URI for this community

https://diglib.eg.org/handle/10.2312/228

Browse

Now showing 1 - 20 of 69

Interactive Visualization with Programmable Graphics Hardware
(Eurographics Association, 2002) Ertl, Thomas
One of the main scientific goals of visualization is the development of algorithms and appropriate data models which facilitate interactive visual analysis and direct manipulation of the increasingly large data sets which result from simulations running on massive parallel computer systems, from measurements employing fast highresolution sensors, or from large databases and hierarchical information spaces. This task can only be achieved with the optimization of all stages of the visualization pipeline: filtering, compression, and feature extraction of the raw data sets, adaptive visualization mappings which allow the users to choose between speed and accuracy, and exploiting new graphics hardware features for fast and high-quality rendering. The recent introduction of advanced programmability in widely available graphics hardware has already led to impressive progress in the area of volume visualization. However, besides the acceleration of the final rendering, flexible graphics hardware is increasingly being used also for the mapping and filtering stages of the visualization pipeline, thus giving rise to new levels of interactivity in visualization applications. The talk will present recent results of applying programmable graphics hardware in various visualization algorithms covering volume data, flow data, terrains, NPR rendering, and distributed and remote applications.
Artificial Animals and Humans: From Physics to Intelligence
(Eurographics Association, 2002) Terzopoulos, Demetri
The confluence of virtual reality and artificial life, an emerging discipline that spans the computational and biological sciences, has yielded synthetic worlds inhabited by realistic, artificial flora and fauna. Artificial animals are complex synthetic organisms that possess functional biomechanical bodies, sensors, and brains with locomotion, perception, behavior, learning, and cognition centers. Artificial humans and other animals are of interest in computer graphics because they are self-animating characters that dramatically advance the state of the art of production animation and interactive game technologies. More broadly, these biomimetic autonomous agents in their realistic virtual worlds also foster deeper, computationally oriented insights into natural living systems.
3D Scanning Technology: Capabilities and Issues
(Eurographics Association, 2002) Scopigno, Roberto
The recent evolution of graphics technology makes it possible to manage very complex models on inexpensive platforms. These impressive rendering capabilities should be paired with detailed and accurate digital models. The construction of high quality 3D models is made easier by the increasing diffusion of automatic 3D measuring devices (often called 3D scanners). These allow to build highly accurate models of real 3D objects in a cost- and time-effective manner. The talk will present the capabilities of this technology focusing mainly on a particular application context: the acquisition of Cultural Heritage artifacts. The peculiar requirements of this domain (high accuracy in the acquisition of both shape and surface appearance, expected low cost and easiness of use of the tools) make it a perfect application example. This talk aims also at presenting and discussing the main issues in the acquisition of accurate 3D models, together with some limitations of current hardware and software tools. Some examples of the results of current projects will be shown.
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.
Tone Reproduction and Physically Based Spectral Rendering
(Eurographics Association, 2002) Devlin, Kate; Chalmers, Alan; Wilkie, Alexander; Purgathofer, Werner
The ultimate aim of realistic graphics is the creation of images that provoke the same responses that a viewer would have to a real scene. This STAR addresses two related key problem areas in this effort which are located at opposite ends of the rendering pipeline, namely the data structures used to describe light during the actual rendering process, and the issue of displaying such radiant intensities in a meaningful way. The interest in the first of these subproblems stems from the fact that it is common industry practice to use RGB colour values to describe light intensity and surface reflectancy. While viable in the context of methods that do not strive to achieve true realism, this approach has to be replaced by more physically accurate techniques if a prediction of nature is intended. The second subproblem is that while research into ways of rendering images provides us with better and faster methods, we do not necessarily see their full effect due to limitations of the display hardware. The low dynamic range of a standard computer monitor requires some form of mapping to produce images that are perceptually accurate. Tone reproduction operators attempt to replicate the effect of real-world luminance intensities. This STAR report will review the work to date on spectral rendering and tone reproduction techniques. It will include an investigation into the need for spectral imagery synthesis methods and accurate tone reproduction, and a discussion of major approaches to physically correct rendering and key tone mapping algorithms. The future of both spectral rendering and tone reproduction techniques will be considered, together with the implications of advances in display hardware.
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.
Visual Data Mining
(Eurographics Association, 2002) Keim, Daniel A.; Müller, Wolfgang; Schumann, Heidrun
Never before in history has data been generated at such high volumes as it is today. Exploring and analyzing the vast volumes of data has become increasingly difficult. Information visualization and visual data mining can help to deal with the flood of information. The advantage of visual data exploration is that the user is directly involved in the data mining process. There are a large number of information visualization techniques that have been developed over the last two decades to support the exploration of large data sets. In this star report, we provide an overview of information visualization and visual data mining techniques, and illustrate them using a few examples.
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.
Geometric Data Structures for Computer Graphics
(Eurographics Association, 2002) Zachmann, Gabriel; Langetepe, Elmar
This tutorial aims at presenting a wide range of geometric data structures, algorithms and techniques from computational geometry to computer graphics practitioners. To achieve this goal we introduce several data structures, discuss their complexity, point out construction schemes and the corresponding performance and present standard applications in two and three dimensions.
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.
Facial Modeling and Animation
(Eurographics Association, 2002) Haber, Jörg; Magnenat-Thalmann, Nadia; Terzopoulos, Demetri; Vetter, Thomas; Blanz, Volker; Kähler, Kolja
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.
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.
Programmable Graphics Hardware for Interactive Visualization
(Eurographics Association, 2002) Ertl, Thomas; Weiskopf, Daniel; Kraus, Martin; Engel, Klaus; Weiler, Manfred; Hopf, Matthias; Röttger, Stefan; Rezk-Salama, Christof
-
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.
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.
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.
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.
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.
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.

Browse

Browsing EG2002 by Issue Date

Results Per Page

Sort Options