EG2003

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Mobile Augmented Reality for Environmental Management (MARE)
(Eurographics Association, 2003) Danado, Jose; Dias, Eduardo; Romao, Teresa; Correia, Nuno; Trabuco, Adelaide; Santos, Carlos; Araujo, David; Duarte, Pedro; Rebocho, Rui; Palmeiro, Jose; Serpa, Joao; Costa, Manuel; Camara, Antonio
Access to real-time data while in field observations is often a requested issue in environmental management. Additionally, it is easier to see that information spatially distributed where it makes sense, leveraging users of the task of searching for the context where the retrieved information can be applied. Augmented Reality (AR) is a technology that allows the superimposition of synthetic images over real images, providing augmented knowledge about the environment in the users vicinity. AR will also make the task more pleasant and effective for the user, since the required information is spatially superimposed over real information related to it. This short paper describes ANTS (Augmented Environments), an AR project for environmental management providing geo-referenced information to the user. The systems architecture has a flexible design based on a client/ server model, where several independent, but functionally interdependent modules are articulated. Therefore, modules can be moved from the server side to the client side or vice-versa, according to the client processing capacity. The system is being deployed in laptop computers and work is in progress to deploy the system using Personal Digital Assistant (PDA) devices. A 3D model and a geo-referenced database are used in the server for user positioning, and presentation components are used in the client to superimpose synthetic information over real images. Several applications for the system are being developed and will also be discussed in this short paper.
Industrial and Project Presentations
(Eurographics Association, 2003) Lozano, Felipe A.; Serón, Francisco
This volume contains the Industrial and Project Presentations for the 24th annual Conference of the European Association for Computer Graphics, EUROGRAPHICS´03, held in Granada, Spain, between the 1st and 6th of September 2003.
Hardware Lighting and Shading
(Eurographics Association, 2003) Kautz, Jan
Traditionally, hardware rasterizers only support the Phong lighting model in combination with Gouraud shading using point light sources. However, the Phong lighting model is strictly empirical and physically implausible. Gouraud shading also tends to undersample the highlight unless a highly tesselated surface is used. Hence, higherquality hardware accelerated lighting and shading has gained much interest in the recent five years. The research on hardware lighting and shading is two-fold. On the one hand, better lighting models for local illumination (assuming point light sources but evaluated per pixel) were demonstrated to be amenable to hardware implementation. On the other hand, recent research has demonstrated that even area lights, represented as environment maps, can be combined with complex lighting models. In both areas, many articles have been published, making it hard to decide, which algorithm is well-suited for which application. This state-of-the-art report will review all relevent articles in both areas, and list advantages and disadvantages of each algorithm.
Implicit Surface Reconstruction and uniform Sampling by Striped Marching Triangles
(Eurographics Association, 2003) Leborán, Víctor; Pardo, Xose M.
The synthesis of computer models from real objects is a usual procedure in medical image processing and reverse engineering. In both cases, the main issues are to reach a topologically consistent and geometrically precise object reconstruction. Implicit surfaces provide a solution to this problem. They define a smooth surface surrounding objects which must be polygonized for an efficient visualization. Due to the increasing size of the application generated data, it becomes necessary to use precise and efficient methods. This work presents a modified method of implicit surface polygonization based on “Marching Triangles”. This modification assures the topological consistency with the initial dataset during the progressive reconstruction of the surface, avoiding overlapping triangles. In addition, a comparison of our method with the marching cubes and the adaptive skeleton climbing algorithms is provided.
Real-Time Simulation of Flexible Materials in Avango Virtual Environment Framework
(Eurographics Association, 2003) Klimenko, Stanislav; Nikitina, Lialia; Nikitin, Igor
his paper describes a system for real-time simulation of linear elastic deformations of volumetric objects in Virtual Environments, implemented in Avango VE Framework 1. The approach makes use of the methods of Finite and Boundary Elements and precomputed Greens functions, and supports real-time interactive deformations of large elastic models, containing more than 10,000 volumetric nodes, at the graphics update rate 85fps.
Realtime Ray Tracing and its use for Interactive Global Illumination
(Eurographics Association, 2003) Wald, Ingo; Purcell, Timothy J.; Schmittler, Jörg; Benthin, Carsten; Slusallek, Philipp
Research on realtime ray tracing has recently made tremendous advances. Algorithmic improvements together with optimized software implementations already allow for interactive frame rates even on a single desktop PC. Furthermore, recent research has demonstrated several options for realizing realtime ray tracing on different hardware platforms, e.g. via streaming computation on modern graphics processors (GPUs) or via the use of dedicated ray tracing chips. Together, these developments indicate that realtime ray tracing might indeed become a reality and widely available in the near future. As most of todays global illumination algorithms heavily rely on ray tracing, this availability of fast ray tracing technology creates the potential to finally compute even global illumination – the physically correct simulation of light transport – at interactive rates. In this STAR, we will first cover the different research activities for realizing realtime ray tracing on different hardware architectures – ranging from shared memory systems, over PC clusters, programmable GPUs, to custom ray tracing hardware. Based on this overview, we discuss some of the advanced issues, such as support for dynamic scenes and designs for a suitable ray tracing API. The third part of this STAR then builds on top of these techniques by presenting algorithms for interactive global illumination in complex and dynamic scenes that may contain large numbers of light sources. We believe that the improved quality and the increased realism that global illumination adds to interactive environments makes it a potential “killer application” for future 3D graphics.
Animating Tree Movement with Sound Effects Generation
(Eurographics Association, 2003) Matsuyama, Katsutsugu; Ota, Shin; Tamura, Machiko; Fujimoto, Tadahiro; Muraoka, Kazunobu; Chiba, Norishige
This video demonstrates the methods for automatically generating tree motions and sound effects for an animation of branches and leaves moving in the wind. Natural motions of leaves and branches swaying in a wind field are created in real-time by our efficient method without using time-consuming physical simulation techniques based on the equations of motion. This method utilizes "1/f ? noise", which is observed in various natural phenomena. Specifically, in this method, the natural motions of leaves and branches are created by calculating appropriate motion angles using 1/f ? noise functions. The realism of the branch motion is enhanced by applying a real-time simple simulation technique based on the spring model. Sound effects are generated as follows: Each tree is divided into branches and leaves, and an independent sound effect generation process is employed for each element. The individual results are then compounded into one sound effect. For the branches, we employ an approach based on the frequencies of experimentally obtained Karman vortex streets. For the leaves, we use the leaf blade state as the input and assume a virtual musical instrument that uses wave tables as the sound source. All computations can be performed independently for each frame step.
The Virtual Painting Paintbox
(Eurographics Association, 2003) Sobczyk, D.; Boyer, V.; Bourdin, J-J.
We present VPUP8 a new kind of paint boxes. It includes a model for the simulation of physic dynamics involved in the painting process and a human-machine interface to manage the position and the moves of the user. Usually digital painting is bounded to a 2D model and a 2D representation. Our 3D model is designed to accurately reproduce the painting process, stroke per stroke. To obtain the subtle details real painting provides, the model needs a very high resolution and the modeling of the picture as a 3D object thick with paint. In front of a real painting, any move brings new impressions.With VPUP8 the position of the user is the main factor of the viewpoint and of the scale of vision computation: from a whole view to a precise zoom-in well adapted to detail work. The position of the user is measured through a non-intrusive face tracker. The images generated prove that VPUP8 is well adapted to any style of painting.
Adaptive quantization with error bounds for compressed view-dependent multiresolution meshes
(Eurographics Association, 2003) Grabner, Markus; Zach, Christopher
We present a simple method to adaptively determine compression parameters according to the given input data. Our method allows to make better use of the available dynamic range (number of bits per component of vertex locations) than with a given fixed-point representation. Moreover, the number of bits per component is also determined adaptively under a user-specified upper bound for the quantization error. Our adaptive quantization method can handle models with largely non-uniform geometric resolution. This is typically the case for manually created models or models derived from different sensors. The experiments we performed demonstrate the benefits of the proposed method.
Improved Indirect Photon Mapping withWeighted Importance Sampling
(Eurographics Association, 2003) Szirmay-Kalos, Laszlo; Szecsi, Laszl
This paper offers a novel approach to the indirect photon mapping method. The placement of photons acting as virtual light sources is regarded as a cheap sampling scheme, allowing for the reuse of a complete shooting path at the cost a single shadow ray. In order to counter for its shortcomings, the variance reduction technique called weighted importance sampling is applied. This allows for the extension of the indirect photon mapping method for specular settings, because the weighting function can mimic surface BRDF characteristics disregarded by the virtual light source placement. On the other hand, weighted importance sampling also helps to eliminate the "corner spikes" caused by the fact that shooting cannot mimic the geometric factor of the connection rays. Advantages and problems are examined for several weighting schemes.
A New 3D Spring for Deformable Object Animation
(Eurographics Association, 2003) Jeong, Il-Kwon; Lee, Inho
A new3D spring for deformable object animation is proposed. Currently mass-spring system is most widely used in a deformable object animation as well as cloth animation. In order to perform a realistic cloth animation using the conventional mass-spring system, one requires three kinds of springs, that is, structural spring, shear spring, and bend spring. Performing a deformable object animation of a given geometric model also requires user’s knowledge or trial-and-error on constructing a stable spring network. For example, a cube model constructed from the edges used in faces for rendering would collapse, and one should use additional springs connecting the vertices inside the cube in order to make a stable spring model for simulation. Using the proposed 3D spring all this tedious and complicated modeling procedure can be omitted and one can easily construct a stable mass and 3D spring model from a geometric model with arbitrary shape. In addition to that, our 3D spring makes it possible to animate sharp folds of a very thin object easily and efficiently without any additional geometrical procedure.
3deSoundBox – a Scalable, Platform-Independent 3D Sound System for Virtual and Augmented Reality Applications
(Eurographics Association, 2003) Stampfl, Philipp
Sound is one of the most important components in animations, presentations and especially immersive environments. Many aspects are recognized more intuitively when sound supports vision and it is easier to follow a story and to believe in a virtual world of illusion. The 3deSoundBox was designed to provide this important acoustic component for such kind of 3D applications in an easy and intuitive way. It is scalable, platform-independent, has an easy to use interface and offers a lot of new possibilities in the field of virtual and augmented reality applications. The 3deSoundBox system can drive any number of speakers and works with any application on any platform with the same range of service. Once programmed, an application can easily take advantage of these features, as it will work on any sound-system with any number of speakers without requiring any changes, due to the scalable architecture of the system.
Low-Level Vertex Programming
(Eurographics Association, 2003) Kraus, Martin
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Alternative Augmented Reality Approaches: Concepts, Techniques, and Applications
(Eurographics Association, 2003) Bimber, Oliver; Raskar, Ramesh
In this tutorial we discuss application specific alternative augmented reality (AR) approaches –such as Virtual Showcases and Shader Lamps– that focus on overcoming some of the limitations linked to conventional AR displays. State-of-the-art concepts, details about hard- and software implementations, and current areas of application are presented. An extensive overview over different stereoscopic and auto-stereoscopic display techniques is given. This enables readers to identify parallels between Virtual Reality and augmented reality displays concepts, and stimulate them to think about alternative approaches for AR. Our focus is on interactive rendering techniques that support display concepts, such as projector-based or spatial optical seethrough AR. Methods that create graphical augmentations with respect to the applied optical elements and display surfaces, and techniques for creating a high level of consistency between real and virtual environments will be discussed. Finally, our experiences made with such technologies within art, edutainment, research and industrial areas will be shared with the audience. By handing out construction drawings and algorithms, we aim at enabling participants to realize such systems on their own.
Point-Based Computer Graphics
(Eurographics Association, 2003) Alexa, Marc; Dachsbacher, Carsten; Gross, Markus; Pauly, Mark; van Baar, Jeroen; Zwicker, Matthias
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Pen and Ink Pictures from Gray-Scale Photographs
(Eurographics Association, 2003) Arroyo, G.; Martín, D.
A new method for producing pen and ink pictures from gray-scale photographs is introduced in this article. It is based on path-finding and reconstruction of strokes. First we apply filters to extract contours from photographs which are converted to strokes, then we show how to modify these strokes in the same way an artist could do it. The strokes are not pixel-based but bspline curves, which are rendered simuling different kinds of brushes and papers.
A Framework for Video-based and Hardware-Accelerated Remote 3D-Visualization
(Eurographics Association, 2003) Goetz, Frank; Domik, Gitta
This paper presents a framework for video-based and hardware-accelerated remote 3d-visualization that produces and delivers high quality video streams at an accurate frame rate. The framework is based on the portable scenegraph system OpenSG, the MPEG4IP package and the Apple Darwin Streaming Server. In realtime generated visualizations will be multicast as an ISO MPEG-4 compliant video stream over the RealTime Streaming Protocol from a server to a client computer. On the client computer a Java program and an ISO MPEG-4 compliant video player are used to interact with the delivered visualization. While using MPEG-4 video streams we can achieve high image quality at a low bandwidth.
Interactive Dynamic Environments Using Image-Based Modeling and Rendering (393.4 kB) Timothy A. Davis, Stephen P. Ficklin An approach to construct augmented CAD models using acquired digital images
(Eurographics Association, 2003) Bianconi, Francesco; Conti, Paolo
An approach for integrating CAD models and information associated with digital images is discussed in this paper. The main objective of the proposed framework is the construction of augmented CAD models using digital images acquired on real components of that models. An approach to associate general shape surfaces with related images is discussed. The proposed method can be used to associate engineering information retrieved through optical methods (thermoelasticity, photoelasticity, surface analysis and similar) with CAD models. The overall architecture and the first outcomes of the implementation of the framework are presented.
Preface
(Eurographics Association, 2003)
Multi-resolution modelling of terrains by using non restricted quadtree triangulation
(Eurographics Association, 2003) Aguilera, A.; Torres, J. C.; Feito, F.
The interactive visualization of terrains requires the processing of a high amount of data in real time, usually it is not possible to work with all of them on main in memory. In this work we present, a method which solves the above problem by means of using spatial indices (quadtree). For that, the terrains are divided into square cells, each of them having a quadtree, which will only be refined up to a the detail level depending on the observer position. With this, allaus to reduce the time used for terrains visualization.

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