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Item 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, AntonioAccess 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.Item Industrial and Project Presentations(Eurographics Association, 2003) Lozano, Felipe A.; Serón, FranciscoThis 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.Item Hardware Lighting and Shading(Eurographics Association, 2003) Kautz, JanTraditionally, 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.Item 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.Item Real-Time Simulation of Flexible Materials in Avango Virtual Environment Framework(Eurographics Association, 2003) Klimenko, Stanislav; Nikitina, Lialia; Nikitin, Igorhis 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.Item Realtime Ray Tracing and its use for Interactive Global Illumination(Eurographics Association, 2003) Wald, Ingo; Purcell, Timothy J.; Schmittler, Jörg; Benthin, Carsten; Slusallek, PhilippResearch 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.Item Animating Tree Movement with Sound Effects Generation(Eurographics Association, 2003) Matsuyama, Katsutsugu; Ota, Shin; Tamura, Machiko; Fujimoto, Tadahiro; Muraoka, Kazunobu; Chiba, NorishigeThis 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.Item 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.Item Adaptive quantization with error bounds for compressed view-dependent multiresolution meshes(Eurographics Association, 2003) Grabner, Markus; Zach, ChristopherWe 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.Item Improved Indirect Photon Mapping withWeighted Importance Sampling(Eurographics Association, 2003) Szirmay-Kalos, Laszlo; Szecsi, LaszlThis 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.