EG2006
Permanent URI for this community
Browse
Browsing EG2006 by Issue Date
Now showing 1 - 20 of 71
Results Per Page
Sort Options
Item Interactive Volume Rendering with Ray Tracing(The Eurographics Association, 2006) Marmitt, Gerd; Friedrich, Heiko; Slusallek, Philipp; Brian Wyvill and Alexander WilkieRecent research on high-performance ray tracing has achieved real-time performance even for highly complex surface models already on a single PC. In this report we provide an overview of techniques for extending real-time ray tracing also to interactive volume rendering. We review fast rendering techniques for different volume representations and rendering modes in a variety of computing environments. The physically-based rendering approach of ray tracing enables high image quality and allows for easily mixing surface, volume, and other primitives in a scene, while fully accounting for all of their optical interactions. We present optimized implementations and discuss the use of upcoming high-performance processors for volume ray tracing.Item Two Layer Image Tile Mosaics(The Eurographics Association, 2006) Kang, Dongwann; Park, Young-Sup; Seo, Sang-Hyun; Yoon, Kyung-Hyun; Dieter Fellner and Charles HansenThis study proposes a method of Two Layer Image Tile Mosaics to preserve detailed depiction of the source image. This method is composed of following three stages. First of all, the upper layer tile is located through a centroidal Voronoi diagram to which an edge avoidance technique is applied, and the position of the lower layer tile is calculated using Delaunay triangulation. Secondly, discover the size and direction field of the tile considering the relation between tiles. Thirdly, adopt a Photomosaics technique to use the image tiles. At this time, the technique of multi-level indexing is used to accelerate the speed of image searching. The Two Layer Image Tile Mosaics obtained through the above process preserve the detailed depiction of source images effectively.Item Articulated Video Sprites(The Eurographics Association, 2006) Vanaken, C.; Gerrits, M.; Bekaert, P.; Dieter Fellner and Charles HansenIn this paper, we present an extension to video sprites for articulated characters. Central to our technique is a matching cost which works on high-level 2D skeletal representations of the characters, instead of their visual appearance. Through a combination of different heuristics, we are able to animate a character according to a new sequence of target skeletons. This way we achieve an accurate matching and a hitherto unseen level of control over the video sprite.Item Real-time Reflection using Ray Tracing with Geometry Field(The Eurographics Association, 2006) Li, Shengying; Fan, Zhe; Yin, Xiaotian; Mueller, Klaus; Kaufman, Arie E.; Gu, Xianfeng; Dieter Fellner and Charles HansenA novel method for accurate reflections in real time is introduced using ray tracing in geometry fields, which combine light fields with geometry images. The geometry field of a surface is defined ray space, mapping a ray to its intersection point with the surface, represented as the uv coordinates on the geometry image. It makes intersection tests much more efficient using lookups within a fragment shader, and allows conventional textures to be applied, such as normal maps, to enhance geometric subtleties. Our method can be generalized to also handle refraction and self-reflection. Experimental results demonstrate its capability for accurate reflection for complex scenes in real-time.Item Digital HPO Hologram Rendering Pipeline(The Eurographics Association, 2006) Janda, M.; Hanák, I.; Skala, V.; Dieter Fellner and Charles HansenThis paper describes a rendering pipeline for digital hologram synthesis. The pipeline is capable of handling triangle meshes, directional light sources, texture coordinates, and advanced illumination models. Due to the huge computational requirements of hologram synthesis only the HPO holograms are considered.Item Toward the Light Field Display: Autostereoscopic Rendering via a Cluster of Projectors(The Eurographics Association, 2006) Yang, Ruigang; Huang, Xinyu; Li, Sifang; Jaynes, Christopher; Dieter Fellner and Charles HansenUltimately, a display device should be capable of reproducing the visual effects that are produced by reality. In this paper we introduce an autostereoscopic display that uses a scalable array of digital light projectors and a projection screen augmented with microlenses to simulate a light field for a given three-dimensional scene. Physical objects emit or reflect light in all directions to create a light field that can be approximated by the light field display. The display can simultaneously provide many viewers from different viewpoints a stereoscopic effect without head-tracking or special mechanical devices. We present a solution to automatically calibrate the light field display and an efficient algorithm to render the special multi-view images it requires by exploiting their spatial coherence. The effectiveness of our approach is demonstrated with a four-projector prototype that can display dynamic imagery with full parallax.Item Enhanced Cartoon and Comic Rendering(The Eurographics Association, 2006) Spindler, Martin; Röber, Niklas; Döhring, Robert; Masuch, Maic; Dieter Fellner and Charles HansenIn this work we present an extension to common cel shading techniques, and describe four new cartoon-like rendering styles applicable for real-time implementations: stylistic shadows, double contour lines, soft cel shading, and pseudo edges. Our work was mainly motivated by the rich set of stylistic elements and expressional possibilities within the medium comic. In particular, we were inspired by Miller s Sin City and McFarlane s Spawn . We designed algorithms for these styles, developed a real-time implementation and integrated it into a regular 3D game engine.Item Modeling Real-time Rendering(The Eurographics Association, 2006) Wong, Chee-Kien Gabriyel; Wang, Jianliang; Dieter Fellner and Charles HansenThe real-time rendering process is well known to be extremely dynamic and complex. This paper presents a novel approach to modeling this process via the system identification methodology. Given the process s dynamic nature arising from the possible myriad variations of render states, polygon streams and the non-linearities involved, we describe a modeling approach using neural networks with supervised training from application-generated data. By comparing the outputs of the neural network model s representation of the rendering process with actual empirical data, we discuss the accuracy of our approach in relation to the practical issues of integrating this study to real-world applications.Item GPU-Based Hierarchical Texture Decompression(The Eurographics Association, 2006) Stachera, J.; Rokita, P.; Dieter Fellner and Charles HansenWe propose a hierarchical texture compression algorithm for real-time decompression on the GPU. Our algorithm is characterized by low computational complexity, random access and hierarchical structure which allow us to access first three levels of encoded mip-map pyramid. The hierarchical texture compression algorithm HiTCg is based on block-wise approach, where each block is subject to local fractal transform.Item Graphics-Based Learning in First-Year Computer Science(The Eurographics Association, 2006) Davis, Timothy A.; Judy Brown and Werner HansmannThis paper proposes a method for teaching a first-year course in computer science using graphicsbased problems as the teaching medium. Specifically, we present a method for instruction in programming using a semester-long project of developing a ray tracer. This effort is part of a larger project, in which a broad range of undergraduate courses are taught using computer graphics as the motivating application. An overview of this project is provided, along with description and results from the first trial CS2 course instructed using this technique.Item Lighting-Up Geometry: Accurate 3D Modelling of Museum Artifacts with a Torch and a Camera(The Eurographics Association, 2006) Vogiatzis, G.; Hernández, C.; Cipolla, R.; Dieter Fellner and Charles HansenThis paper addresses the problem of obtaining complete, very detailed reconstructions of shiny objects such as glazed ceramics. We present an algorithm which uses silhouettes of the object, as well as images obtained under changing illumination conditions. In contrast with previous photometric stereo techniques, ours is not limited to a single viewpoint but produces accurate reconstructions in full 3D. A number of images of the object are obtained from multiple viewpoints, under varying lighting conditions. Starting from the silhouettes, the algorithm recovers camera motion and constructs the object s visual hull. This is then used to recover the illumination and initialise a multi-view photometric stereo scheme to obtain a closed surface reconstruction. The algorithm has been implemented as a practical model acquisition system. Here, we present a number of complete reconstructions of challenging real objects.Item GPUGI: Global Illumination Effects on the GPU(The Eurographics Association, 2006) Szirmay-Kalos, Laszlo; Szecsi, Laszlo; Sbert, Mateu; Nadia Magnenat-Thalmann and Katja BühlerIn this tutorial we explain how global illumination rendering methods can be implemented on Shader Model 3.0 GPUs. These algorithms do not follow the conventional local illumination model of Di- rectX/OpenGL pipelines, but require global geometric or illumination information when shading a point. In addition to the theory and state of the art of these approaches, we go into the details of a few algorithms, including mirror reflections, reflactions, caustics, diffuse/glossy indirect illumination, precomputation aided global illumination for surface and volumetric models, obscurances and tone mapping, also giving their GPU implementation in HLSL or Cg language.Item Fast Skeletal Animation by skinned Arc-Spline based Deformation(The Eurographics Association, 2006) Forstmann, Sven; Ohya, Jun; Dieter Fellner and Charles HansenPresented is a novel skeletal animation system for providing high quality geometric deformations in real-time. Each bone of the skeleton is therefore represented by a spline, rather than using conventional matrix rotation. In our approach, each vertex of the animated character can be influenced by a maximum of three spline-curves, which is sufficient for skinned animation. One spline is parameterized by three control points and a possible twist. As opposed to conventional Bézier curves does our arc-spline rely on trigonometric functions for providing better curvatures. The optimized implementation using the OpenGL-shading language shows very promising results for real-time character animation, as even about 1 Million vertices were able to be transformed at interactive 43 frames per second on a GeForce 7800 GTX graphics card.Item Clothing the Masses: Real-Time Clothed Crowds With Variation(The Eurographics Association, 2006) Dobbyn, S.; McDonnell, R.; Kavan, L.; Collins, S.; O'Sullivan, C.; Dieter Fellner and Charles HansenThe animation and rendering of crowds of realistically clothed characters presents a difficult challenge in computer graphics, which is further exacerbated when real-time frame rates are required. To date, due to real-time constraints, standard skinning methods have been used to animate the clothes of individuals in real-time crowds, which does not create the appropriate secondary motion for flowing garments. However, plausible cloth simulation is vital for the depiction of realistic characters, so we have developed a novel crowd system in which the individuals are endowed with realism and variety through the addition of physically simulated clothing and hardware assisted pattern variation.Item Building Expression into Virtual Characters(The Eurographics Association, 2006) Vinayagamoorthy, V.; Gillies, M.; Steed, A.; Tanguy, E.; Pan, X.; Loscos, C.; Slater, M.; Brian Wyvill and Alexander WilkieVirtual characters are an important part of many 3D graphical simulations. In entertainment or training applications, virtual characters might be one of the main mechanisms for creating and developing content and scenarios. In such applications the user may need to interact with a number of different characters that need to invoke specific responses in the user, so that the user interprets the scenario in the way that the designer intended. Whilst representations of virtual characters have come a long way in recent years, interactive virtual characters tend to be a bit "wooden" with respect to their perceived behaviour. In this STAR we give an overview of work on expressive virtual characters. In particular, we assume that a virtual character representation is already available, and we describe a variety of models and methods that are used to give the characters more "depth" so that they are less wooden and more plausible. We cover models of individual characters emotion and personality, models of interpersonal behaviour and methods for generating expression.Item Elastic Facial Caricature Warping(The Eurographics Association, 2006) Clarke, Lyndsey; Chen, Min; Townsend, Peter; Mora, Benjamin; Dieter Fellner and Charles HansenCaricatures are usually created by skilled artists, and, due to their amusing appearance, they serve mainly as a source of entertainment and humour. This short paper is therefore concerned with a means for generating facial caricatures from given photographs using image warping. In particular, we propose to assign virtual physical and material properties to various facial features in order to specify and render exaggerated transformations in an intuitive manner. Though our objective is not for creating physically accurate photorealism, our physically-based approach enables users to associate virtual displacements in caricatures, with common physical phenomena.Item Rendering Plasma Phenomena: Applications and Challenges(The Eurographics Association, 2006) Baranoski, G. V. G.; Rokne, J. G.; Brian Wyvill and Alexander WilkiePlasmas are ubiquitous in the Universe. An understanding of plasma phenomena is therefore of importance for almost every area of astrophysics, from stellar atmospheres to star clusters. Plasmas also occur in daily life both in industrial processes and in consumer products. Recent groundbreaking data is making this the golden age of plasma science. Although direct observations and analysis of data provide important physical evidence for plasma phenomena, they do not necessarily explain the phenomena. Hence, recent discoveries in this area might not only arise out of observations, but also from visual simulations of the phenomena supported by advanced rendering technologies. This report describes the state of art of such simulations, and examines practical issues often overlooked in the literature. Their educational and public outreach applications are also discussed. Although the emphasis is on the predictive rendering of plasma processes, the simulation guidelines and trade-offs addressed in this report can be extended to the general simulation of natural phenomena. The report closes with a discussion of further avenues of research involving the simulation of plasma phenomena.Item Collision Handling and its Applications(The Eurographics Association, 2006) Teschner, Matthias; Cani, Marie-Paule; Fedkiw, Ron; Bridson, Robert; Redon, Stephane; Volino, Pascal; Zachmann, Gabriel; Nadia Magnenat-Thalmann and Katja BühlerIn contrast to real-world scenarios, object representations in virtual environments have no notion of interpenetration. Therefore, algorithms for the detection of interfering object representations are an essential component in virtual environments. Applications are wide-spread and can be found in areas such as surgery simulation, games, cloth simulation, and virtual prototyping. Early collision detection approaches have been presented in robotics and computational geometry more than twenty years ago. Nevertheless, collision detection is still a very active research topic in computer graphics. This ongoing interest is constantly documented by new results presented in journals and at major conferences, such as Siggraph and Eurographics. In order to enable a realistic behavior of interacting objects in dynamic simulations, collision detection algorithms have to be accompanied by collision response schemes.Item Multiresolution GPU Mesh Painting(The Eurographics Association, 2006) Ritschel, Tobias; Botsch, Mario; Müller, Stefan; Dieter Fellner and Charles HansenMesh painting is a well accepted and very intuitive metaphor for adding high-resolution detail to a given 3D model: Using a brush interface, the designer simply paints fine-scale texture or geometry information onto the surface. In this paper we propose a fully GPU-accelerated mesh painting technique, which provides real-time feedback even for highly complex meshes. Our method can handle arbitrary input meshes, which are considered as base meshes for Catmull-Clark subdivision. Representing the surface by an atlas of geometry images and exploiting programmable vertex and fragment shaders allows for highly efficient LoD rendering and surface manipulation. Our painting metaphor supports real-time texturing, sculpting, smoothing, and multiresolution surface deformations.Item 3D Role-Playing Games as Language Learning Tools(The Eurographics Association, 2006) Rankin, Yolanda; Gold, Rachel; Gooch, Bruce; Judy Brown and Werner HansmannLeveraging the experiential cognition and motivational factors of 3D games, we conduct a pilot study that utilizes Ever Quest 2 as pedagogical learning tool for English as a second language (ESL) students. We combine the benefits of massive multiplayer online role-playing games (MMORPGs) and second language methodology to create a digital learning environment for second language acquisition (SLA). Rather than using traditional computerassisted language learning (CALL) software, we explore the immersive, virtual environment of Ever Quest 2 as ESL participants assume virtual identities and engage in social interactions within the game world. We suggest that language becomes a crucial artifact for character development and completion of game tasks in the virtual world. Preliminary results demonstrate that Ever Quest 2 intermediate and advanced ESL students increase their English vocabulary by 40% as result of game play interactions with non-playing characters (NPCs). Furthermore, intermediate and advanced ESL students practice their conversational skills with playing characters (PCs), generating a 100% increase in chat messages during eight sessions of game play. These results lead to the conclusion that MMORPGs can provide motivation and adequate language learning support for intermediate and advanced ESL students.