Volume 21 (2002)

Permanent URI for this community

https://diglib.eg.org/handle/10.2312/103

Browse

Now showing 1 - 20 of 100

Efficient Fitting and Rendering of Large Scattered Data Sets Using Subdivision Surfaces
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheib, Vincent; Haber, Jorg; Lin, Ming C.; Seidel, Hans-Peter
We present a method to efficiently construct and render a smooth surface for approximation of large functional scattered data. Using a subdivision surface framework and techniques from terrain rendering, the resulting surface can be explored from any viewpoint while maintaining high surface fairness and interactive frame rates. We show the approximation error to be sufficiently small for several large data sets. Our system allows for adaptive simplification and provides continuous levels of detail, taking into account the local variation and distribution of the data.Categories and Subject Descriptors (according to ACM CCS): G.1.2 [Approximation]: Approximation of surfaces, Least squares approximation, Piecewise polynomial approximation; I.3.3 [Picture/Image Generation]: Display algorithms, Viewing algorithms; I.3.5 [Computational Geometry and Object Modeling]: Surface representation.
Texture Particles
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Dischler, J.-M.; Maritaud, K.; Levy, B.; Ghazanfarpour, D.
This paper presents an analytical extension of texture synthesis techniques based on the distribution of elementary texture components. Our approach is similar to the bombing, cellular, macrostructured and lapped textures techniques, but provides the user with more control on both the texture analysis and synthesis phases. Therefore, high quality results can be obtained for a large number of structured or stochastic textures (bricks, marble, lawn, etc.). The analysis consists in decomposing textures into elementary components - that we call 'texture particles' - and for which we analyze their specific spatial arrangements. The synthesis then consists in recomposing similar textures directly on arbitrary surfaces by taking into account the previously computed arrangements, extended to 3D surfaces. Compared to 'pixel-based' analysis and synthesis methods, which have been recently generalized to arbitrary surfaces, our approach has three major advantages: (1) it is fast, which allows the user to interactively control the synthesis process. This further allows us to propose a large number of tools, granting a high degree of artistic freedom to the user. (2) It avoids the visual deterioration of the texture components by preserving their shapes as well as their spatial arrangements. (3) The texture particles can be not only images, but also 3D geometric elements, which extends significantly the domain of application.
A Coherence-based Collision Detection Method for Dressed Human Simulation
(Blackwell Publishers Ltd and the Eurographics Association, 2002) Zhang, Dongliang; Yuen, Matthew
In this paper, paper we present a coherence-based method to detect collisions between the garment and human model for dressed human simulations. Based on the property of coherence, collisions can be rapidly detected by tracking the movement of the most likely geometric elements to collide. The voxel technique is employed to quickly identify the potential collision region. Experimental results show that our method is very efficient.
Real-time Animation of Dressed Virtual Humans
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Cordier, Frederic; Magnenat-Thalmann, Nadia
In this paper, we describe a method for cloth animation in real-time. The algorithm works in a hybrid manner exploiting the merits of both the physical-based and geometric deformations. It makes use of predetermined conditions between the cloth and the body model, avoiding complex collision detection and physical deformations wherever possible. Garments are segmented into pieces that are simulated by various algorithms, depending on how they are laid on the body surface and whether they stick or flow on it. Tests show that the method is well suited to fully dressed virtual human models, achieving real-time performance compared to ordinary cloth-simulations.
Interactive Visualization with Programmable Graphics Hardware
(Blackwell Publishers, Inc and the 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 high-resolution 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.
Using Perceptual Texture Masking for Efficient Image Synthesis
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Walter, Bruce; Pattanaik, Sumanta N.; Greenberg, Donald P.
Texture mapping has become indispensable in image synthesis as an inexpensive source of rich visual detail. Less obvious, but just as useful, is its ability to mask image errors due to inaccuracies in geometry or lighting. This ability can be used to substantially accelerate rendering by eliminating computations when the resulting errors will be perceptually insignificant.Our new method precomputes the masking ability of textures using aspects of the JPEG image compression standard. This extra information is stored as threshold elevation factors in the texture's mip-map and interpolated at image generation time as part of the normal texture lookup process. Any algorithm which uses error tolerances or visibility thresholds can then take advantage of texture masking. Applications to adaptive shadow testing, irradiance caching, and path tracing are demonstrated.Unlike prior methods, our approach does not require that initial images be computed before masking can be exploited and incurs only negligible runtime computational overhead. Thus, it is much easier to integrate with existing rendering systems for both static and dynamic scenes and yields computational savings even when only small amounts of texture masking are present.Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Color, shading, shadowing, and texture
22nd EUROGRAPHICS General Assembly
(Blackwell Publishers Ltd and the Eurographics Association, 2002)
SIGGRAPH 2001
(Blackwell Publishers Ltd and the Eurographics Association, 2002)
Artistic Surface Rendering Using Layout of Text
(Blackwell Publishers Ltd and the Eurographics Association, 2002) Surazhsky, Tatiana; Elber, Gershon
An artistic rendering method of free-form surfaces with the aid of half-toned text that is laid-out on the given surface is presented. The layout of the text is computed using symbolic composition of the free-form parametric surface S(u, v) with cubic or linear Bezier curve segments C(t) = cu (t), cv (t), comprising the outline of the text symbols. Once the layout is constructed on the surface, a shading process is applied to the text, affecting the width of the symbols as well as their color, according to some shader function. The shader function depends on the surface orientation and the view direction as well as the color and the direction or position of the light source.
Modeling Surperspective Projection of Landscapes for Geographical Guide-Map Generation
(Blackwell Science Ltd and the Eurographics Association, 2002) Takahashi, Shigeo; Ohta, Naoya; Nakamura, Hiroko; Takeshima, Yuriko; Fujishiro, Issei
It is still challenging to generate hand-drawn pictures because they differ from ordinary photographs in that they are often drawn as seen from multiple viewpoints. This paper presents a new approach for modeling such surperspective projection based on shape deformation techniques. Specifically, surperspective landscape images for guide-maps are generated from 3D geographical elevation data. Our method first partitions a target geographical surface into feature areas to provide designers with landmarks suitable for editing. The system takes as input 2D visual effects, which are converted to 3D geometric constraints for geographical surface deformation. Using ordinary perspective projection, the deformed shape is then transformed into a target guide-map image where each landmark enjoys its own vista points. An algorithm for calculating such 2D visual effects semi-automatically from the geographical shape features is also considered.
Eurographics 2001
(Blackwell Publishers Ltd and the Eurographics Association, 2002)
The 3D Model Acquisition Pipeline
(Blackwell Publishers Ltd and the Eurographics Association, 2002) Bernardini, Fausto; Rushmeier, Holly
Three-dimensional (3D) image acquisition systems are rapidly becoming more affordable, especially systems based on commodity electronic cameras. At the same time, personal computers with graphics hardware capable of displaying complex 3D models are also becoming inexpensive enough to be available to a large population. As a result, there is potentially an opportunity to consider new virtual reality applications as diverse as cultural heritage and retail sales that will allow people to view realistic 3D objects on home computers.Although there are many physical techniques for acquiring 3D data-including laser scanners, structured light and time-of-flight-there is a basic pipeline of operations for taking the acquired data and producing a usable numerical model. We look at the fundamental problems of range image registration, line-of-sight errors, mesh integration, surface detail and color, and texture mapping. In the area of registration we consider both the problems of finding an initial global alignment using manual and automatic means, and refining this alignment with variations of the Iterative Closest Point methods. To account for scanner line-of-sight errors we compare several averaging approaches. In the area of mesh integration, that is finding a single mesh joining the data from all scans, we compare various methods for computing interpolating and approximating surfaces. We then look at various ways in which surface properties such as color (more properly, spectral reflectance) can be extracted from acquired imagery. Finally, we examine techniques for producing a final model representation that can be efficiently rendered using graphics hardware.
Computer Graphics forum
(Blackwell Publishers, Inc and the Eurographics Association, 2002)
Eurographics and Computer Graphics forum offer a variety of services on the international networks. You can find details ofour latest events, how to prepare a paper for the conference or for the journal and much more besides. This information can beaccessed mainly through the EG website but we also offer some support for ftp and mail server access.
Hardware Accelerated Interactive Vector Field Visualization: A level of detail approach
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Bordoloi, Udeepta; Shen, Han-Wei
This paper presents an interactive global visualization technique for dense vector fields using levels of detail. We introduce a novel scheme which combines an error-controlled hierarchical approach and hardware acceleration to produce high resolution visualizations at interactive rates. Users can control the trade-off between computation time and image quality, producing visualizations amenable for situations ranging from high frame-rate previewing to accurate analysis. Use of hardware texture mapping allows the user to interactively zoom in and explore the data, and also to configure various texture parameters to change the look and feel of the visualization. We are able to achieve sub-second rates for dense LIC-like visualizations with resolutions in the order of a million pixels for data of similar dimensions.Categories and Subject Descriptors (according to ACM CCS): I.3 [Computer Graphics]: Applications
Siggraph 2002
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Laycock, Stephen D.; Laycock, Robert G.
Deferred, Self-Organizing BSP Trees
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Ar, Sigal; Montag, Gil; Tal, Ayellet
bsptrees and KD trees are fundamental data structures for collision detection in walkthrough environments. A basic issue in the construction of these hierarchical data structures is the choice of cutting planes. Rather than base these choices solely on the properties of the scene, we propose using information about how the tree is used in order to determine its structure. We demonstrate how this leads to the creation ofbsptrees that are small, do not require much preprocessing time, and respond very efficiently to sequences of collision queries.Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling I.3.6 [Computer Graphics]: Graphics data structures and data types, Interaction techniques I.3.7 [Computer Graphics]: Virtual reality
Adaptive Zooming in Web Cartography
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Cecconi, Alesandro; Galanda, Martin
Beyond any doubt much of the current web mapping and web GIS applications lack cartographic quality. Thereasons aren't only the technical limitations related to Internet delivery, but also the neglect of one of the maincartographic principles of digital mapping, namely adaptive zooming. Adaptive zooming describes the adjustmentof a map, its contents and the symbolization to target scale in consequence of a zooming operation. The approachdescribed in this paper proposes the combination of two commonly known concepts: on the one hand levelsof detail (LoD) for those object classes, that require high computational cost for the automated generalizationprocess (e.g. buildings, road network); on the other hand an on-the-fly generalization for those object classeswhich can be generalized by less complex methods and algorithms (e.g. rivers, lakes). Realizing such interactiveand dynamic concept for web mapping requires the use of vector based visualization tools. The data format bestmeeting the criteria is the W3C standard Scalable Vector Graphics (SVG). Thus, it has been used to implementthe presented ideas in a prototype application for topographic web mapping based on the landscape modelVECTOR25 of the Swiss Federal Office of Topography.
Advanced Radiance Estimation For Photon Map Global Illumination
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Hey, Heinrich; Purgathofer, Werner
We present a new method to compute radiance in photon map based global illumination simulation for polygonal scenes with general bidirectional scattering distribution functions (BSDFs). Our new radiance estimation uses the actual geometry in the neighborhood of the illuminated point, and does not assume that the nearest neighbor photons lie in the same plane as the point, nor that they are distributed in a circular area around that point. This allows us to achieve accurate indirect illumination by direct visualization of the photon map - which is especially important for the simulation of caustics(LS+DS*Epaths) - even in the vicinity of edges and corners of objects, and on surfaces with differently oriented small geometric details.
Projective Texture Mapping with Full Panorama
(Blackwell Publishers, Inc and the Eurographics Association, 2002) Kim, Dongho; Hahn, James K.
Projective texture mapping is used to project a texture map onto scene geometry. It has been used in many applications, since it eliminates the assignment of fixed texture coordinates and provides a good method of representing synthetic images or photographs in image-based rendering. But conventional projective texture mapping has limitations in the field of view and the degree of navigation because only simple rectangular texture maps can be used.In this work, we propose the concept of panoramic projective texture mapping (PPTM). It projects cubic or cylindrical panorama onto the scene geometry. With this scheme, any polygonal geometry can receive the projection of a panoramic texture map, without using fixed texture coordinates or modeling many projective texture mapping. For fast real-time rendering, a hardware-based rendering method is also presented. Applications of PPTM include panorama viewer similar to QuicktimeVR and navigation in the panoramic scene, which can be created by image-based modeling techniques.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Viewing Algorithms; I.3.7 [Computer Graphics]: Color, Shading, Shadowing, and Texture
Recent Advances in Mesh Morphing
(Blackwell Publishers Ltd and the Eurographics Association, 2002) Alexa, Marc
Meshes have become a widespread and popular representation of models in computer graphics. Morphing techniques aim at transforming a given source shape into a target shape. Morphing techniques have various applications ranging from special effects in television and movies to medical imaging and scientific visualization. Not surprisingly, morphing techniques for meshes have received a lot of interest lately.This work sums up recent developments in the area of mesh morphing. It presents a consistent framework to classify and compare various techniques approaching the same underlying problems from different angles.

Browse

Browsing Volume 21 (2002) by Issue Date

Results Per Page

Sort Options