STARs 2006
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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 Camera Control in Computer Graphics(The Eurographics Association, 2006) Christie, Marc; Olivier, Patrick; Brian Wyvill and Alexander WilkieProgress in modeling, animation and rendering means that rich, high fidelity interactive virtual worlds are now commonplace. But as photographers and cinematographers know, achievement of the intended informational and aesthetic goals is highly dependent on the position and motion of the camera in relation to the elements of the scene. Camera control encompasses interactive approaches, semi-automatic camera positioning, and fully declarative approaches to the management of a user's viewpoint on a scene. Camera control is required in nearly all interactive 3D applications and presents a particular combination of technical challenges for which there have been a number of recent proposals (e.g. specific path-planning, management of occlusion, modeling of high-level communicative goals). We present, classify the approaches, analyze the requirements and limits of solving techniques and explore in detail the main difficulties and challenges in automatic camera control.Item Computational Photography(The Eurographics Association, 2006) Raskar, Ramesh; Tumblin, Jack; Mohan, Ankit; Agrawal, Amit; Li, Yuanzen; Brian Wyvill and Alexander WilkieComputational photography combines plentiful computing, digital sensors, modern optics, actuators, probes and smart lights to escape the limitations of traditional film cameras and enables novel imaging applications. Unbounded dynamic range, variable focus, resolution, and depth of field, hints about shape, reflectance, and lighting, and new interactive forms of photos that are partly snapshots and partly videos are just some of the new applications found in Computational Photography. The computational techniques encompass methods from modification of imaging parameters during capture to sophisticated reconstructions from indirect measurements. We provide a practical guide to topics in image capture and manipulation methods for generating compelling pictures for computer graphics and for extracting scene properties for computer vision, with several examples. Many ideas in computational photography are still relatively new to digital artists and programmers and there is no upto- date reference text. A larger problem is that a multi-disciplinary field that combines ideas from computational methods and modern digital photography involves a steep learning curve. For example, photographers are not always familiar with advanced algorithms now emerging to capture high dynamic range images, but image processing researchers face difficulty in understanding the capture and noise issues in digital cameras. These topics, however, can be easily learned without extensive background. The goal of this STAR is to present both aspects in a compact form. The new capture methods include sophisticated sensors, electromechanical actuators and on-board processing. Examples include adaptation to sensed scene depth and illumination, taking multiple pictures by varying camera parameters or actively modifying the flash illumination parameters. A class of modern reconstruction methods is also emerging. The methods can achieve a photomontage by optimally fusing information from multiple images, improve signal to noise ratio and extract scene features such as depth edges. The STAR briefly reviews fundamental topics in digital imaging and then provides a practical guide to underlying techniques beyond image processing such as gradient domain operations, graph cuts, bilateral filters and optimizations. The participants learn about topics in image capture and manipulation methods for generating compelling pictures for computer graphics and for extracting scene properties for computer vision, with several examples. We hope to provide enough fundamentals to satisfy the technical specialist without intimidating the curious graphics researcher interested in recent advances in photography. The intended audience is photographers, digital artists, image processing programmers and vision researchers using or building applications for digital cameras or images. They will learn about camera fundamentals and powerful computational tools, along with many real world examples.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 Preface and Table of Contents(The Eurographics Association, 2006) -; Brian Wyvill and Alexander WilkiePreface and Table of ContentsItem 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 Segmentation and Shape Extraction of 3D Boundary Meshes(The Eurographics Association, 2006) Shamir, Ariel; Brian Wyvill and Alexander WilkieIn this report we present the state of the art on segmentation, or partitioning techniques used on boundary meshes. Recently, these have become a part of many mesh and object manipulation algorithms in computer graphics. We formulation the segmentation problem as an optimization problem and identify two primarily distinct types of mesh segmentation, namely parts segmentation and patch segmentation. We classify previous segmentation solutions according to the different segmentation goals, the optimization criteria and features used, and the various algorithmic techniques employed. We also present generic algorithms for the major techniques of segmentation.