Volume 24 (2005)
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Item 2004 Eurographics Symposium on Parallel Graphics and Visualization(The Eurographics Association and Blackwell Publishing Ltd., 2005) Raffin, BrunoItem 26th EUROGRAPHICS General Assembly(The Eurographics Association and Blackwell Publishing Ltd., 2005)Item 3D Posture Reconstruction and Human Animation from 2D Feature Points(The Eurographics Association and Blackwell Publishing Ltd., 2005) Zhao, Jianhui; Li, Ling; Chee Keong, KwohAn optimal approach is proposed in this paper for posture reconstruction and human animation from 2D feature points extracted from the monocular images containing human motions. Biomechanical constraints are encoded in every joint of the adopted 3D skeletal human model to make sure that each state of the joints represents a physically valid posture. Size of the human model is adjusted to be consistent with the human figure represented by feature points. Energy Function is defined to represent the residuals between the extracted 2D feature points and the corresponding features resulted from projection of the 3D human model. Local Adjustment and Global Adjustment procedures are proposed to place the joints and body segments into proper locations and orientations in 3D space to create the posture with the minimum value of Energy Function. To find the optimal solution of the ill-posed recovery problem from 2D to 3D, Genetic Algorithm is employed in the high-dimensional parameter space by considering all the parameters simultaneously. Smooth and continuous changes between consecutive frames are considered in development of the human animation procedure. The proposed approach produces optimal reconstruction results of any possible human postures and movements. It is different from classical kinematics and dynamics formulations, and is an attempt to bridge the gap between computer vision and computer animation in human motion study.Item Acquisition, Synthesis, and Rendering of Bidirectional Texture Functions(The Eurographics Association and Blackwell Publishing Ltd., 2005) Mueller, G.; Meseth, J.; Sattler, M.; Sarlette, R.; Klein, R.One of the main challenges in computer graphics is still the realistic rendering of complex materials such as fabric or skin. The difficulty arises from the complex meso structure and reflectance behavior defining the unique look-and-feel of a material. A wide class of such realistic materials can be described as 2D-texture under varying light- and view direction, namely, the Bidirectional Texture Function (BTF). Since an easy and general method for modeling BTFs is not available, current research concentrates on image-based methods, which rely on measured BTFs (acquired real-world data) in combination with appropriate synthesis methods. Recent results have shown that this approach greatly improves the visual quality of rendered surfaces and therefore the quality of applications such as virtual prototyping. This state-of-the-art report (STAR) will present the techniques for the main tasks involved in producing photo-realistic renderings using measured BTFs in details.Item Adaptive Deformable Models for Graphics and Vision(The Eurographics Association and Blackwell Publishing Ltd., 2005) Goldenstein, Siome; Vogler, Christian; Velho, LuizDeformable models are a powerful tool in both computer graphics and computer vision. The description and implementation of the deformations have to be simultaneously flexible and powerful, otherwise the technique may not satisfy the requirements of all the distinct applications. In this paper, we introduce a new method for the deformable model specification: deformable fields. Deformable fields are conceptually simple, lead to an easy implementation, and are suitable for adaptive models. We apply our new technique to describe an adaptive deformable face, and compare three different adaptation strategies. We show how our technique is suitable to describe different individuals, how to construct a model based on information from a single image, and how it allows the tracking of the deformation parameters over a video sequence.Item Adaptive Instant Displays: Continuously Calibrated Projections Using Per-Pixel Light Control(The Eurographics Association and Blackwell Publishing, Inc, 2005) Cotting, Daniel; Ziegler, Remo; Gross, Markus; Fuchs, HenryItem Algorithms for Interactive Editing of Level Set Models(The Eurographics Association and Blackwell Publishing Ltd., 2005) Museth, Ken; Breen, David E.; Whitaker, Ross T.; Mauch, Sean; Johnson, DavidLevel set models combine a low-level volumetric representation, the mathematics of deformable implicit surfaces and powerful, robust numerical techniques to produce a novel approach to shape design. While these models offer many benefits, their large-scale representation and numerical requirements create significant challenges when developing an interactive system. This paper describes the collection of techniques and algorithms (some new, some pre-existing) needed to overcome these challenges and to create an interactive editing system for this new type of geometric model. We summarize the algorithms for producing level set input models and, more importantly, for localizing/minimizing computation during the editing process. These algorithms include distance calculations, scan conversion, closest point determination, fast marching methods, bounding box creation, fast and incremental mesh extraction, numerical integration and narrow band techniques. Together these algorithms provide the capabilities required for interactive editing of level set models.Item Anti-Aliased Lines Using Run-Masks(The Eurographics Association and Blackwell Publishing Ltd., 2005) Diakopoulos, Nicholas A.; Stephenson, Peter D.In recent work, a set of line digitization algorithms based on the hierarchy of runs in the digital line has unified and generalized the iterative line-drawing algorithms used in computer graphics. In this paper, the additional structural information generated by these algorithms is leveraged to describe a run-based approach to draw anti-aliased line segments in which anti-aliased run-masks are substituted for the individual run lengths as the line is being drawn. The run-masks are precomputed using a prefiltering technique such that one or more run-masks are defined for each of the one or two possible run lengths that occur in the line. The run-masks can be defined for any order or level of the hierarchy of runs in the digital line and the technique is illustrated using runs of pixels. Comparing the use of run-masks to applying the prefiltering technique for each pixel in the line, a line of similar visual quality can be produced more efficiently. We place no restrictions on the placement of the end points of the line, which may reside anywhere on the two-dimensional plane.Item Approximate Ray-Tracing on the GPU with Distance Impostors(The Eurographics Association and Blackwell Publishing, Inc, 2005) Szirmay-Kalos, Laszlo; Aszodi, Barnabas; Lazanyi, Istvan; Premecz, MatyasItem Approximation of a Variable Density Cloud of Points by Shrinking a Discrete Membrane(The Eurographics Association and Blackwell Publishing Ltd., 2005) Esteve, Jordi; Brunet, Pere; Vinacua, AlvarThis paper describes a method to obtain a closed surface that approximates a general 3D data point set with nonuniform density. Aside from the positions of the initial data points, no other information is used. Particularly, neither the topological relations between the points nor the normal to the surface at the data points are needed. The reconstructed surface does not exactly interpolate the initial data points, but approximates them with a bounded maximum distance. The method allows one to reconstruct closed surfaces with arbitrary genus and closed surfaces with disconnected shells.Item Author Index Volume 24 (2005)(The Eurographics Association and Blackwell Publishing Ltd., 2005)Item Automatic Generation of Structure Preserving Multiresolution Models(The Eurographics Association and Blackwell Publishing, Inc, 2005) Marinov, M.; Kobbelt, L.Item Automatic Synchronization of Background Music and Motion in Computer Animation(The Eurographics Association and Blackwell Publishing, Inc, 2005) Lee, Hyun-Chul; Lee, In-KwonItem A Bidirectional Deposition Model of Wax Crayons(The Eurographics Association and Blackwell Publishing Ltd., 2005) Rudolf, Dave; Mould, David; Neufeld, EricWe present a physically inspired model of wax crayons, which synthesizes drawings from collections of user-specified strokes. Paper is represented by a height-field texture, and a crayon is modeled with a 2D mask that evolves as it interacts with the paper. The amount of wax deposition is computed based on the crayon contact profile, contact force and friction. Previously deposited wax is smeared by crayon action, based on wax softness and contact information. Deposited wax can also be carved from the paper by the crayon and redeposited at another location. The distributed wax is rendered using a simplified Kubelka-Monk model, which approximates light transmission and scattering effects.Item BRDF and geometry capture from extended inhomogeneous samples using flash photography(The Eurographics Association and Blackwell Publishing, Inc, 2005) Paterson, James A.; Claus, David; Fitzgibbon, Andrew W.Item CGForum 2005 Cover Image(The Eurographics Association and Blackwell Publishing Ltd., 2005)Item Collision Detection for Deformable Objects(The Eurographics Association and Blackwell Publishing Ltd., 2005) Teschner, M.; Kimmerle, S.; Heidelberger, B.; Zachmann, G.; Raghupathi, L.; Fuhrmann, A.; Cani, M.-P.; Faure, F.; Magnenat-Thalmann, N.; Strasser, W.; Volino, P.Interactive environments for dynamically deforming objects play an important role in surgery simulation and entertainment technology. These environments require fast deformable models and very efficient collision handling techniques. While collision detection for rigid bodies is well investigated, collision detection for deformable objects introduces additional challenging problems. This paper focuses on these aspects and summarizes recent research in the area of deformable collision detection. Various approaches based on bounding volume hierarchies, distance fields and spatial partitioning are discussed. In addition, image-space techniques and stochastic methods are considered. Applications in cloth modeling and surgical simulation are presented.Item Constrained Visualization Using the Shepard Interpolation Family(The Eurographics Association and Blackwell Publishing Ltd., 2005) Brodlie, K. W.; Asim, M. R.; Unsworth, K.This paper discusses the problem of visualizing data where there are underlying constraints that must be preserved. For example, we may know that the data are inherently positive. We show how the Modified Quadratic Shepard method, which interpolates scattered data of any dimensionality, can be constrained to preserve positivity. We do this by forcing the quadratic basis functions to be positive. The method can be extended to handle other types of constraints, including lower bound of 0 and upper bound of 1-as occurs with fractional data. A further extension allows general range restrictions, creating an interpolant that lies between any two specified functions as the lower and upper bounds.Item Cubical Marching Squares: Adaptive Feature Preserving Surface Extraction from Volume Data(The Eurographics Association and Blackwell Publishing, Inc, 2005) Ho, Chien.-Chang; Wu, Fu-Che; Chen, Bing-Yu; Chuang, Yung-Yu; Ouhyoung, MingItem Cutting and Pasting Irregularly Shaped Patches for Texture Synthesis(The Eurographics Association and Blackwell Publishing Ltd., 2005) Dong, Feng; Lin, Hai; Clapworthy, GordonThis paper proposes a patch-based texture synthesis approach that cuts and stitches irregularly shaped texture patches to generate new texture images with minimized visual discontinuity. It works well on a wide range of textures. A semiautomatic algorithm is developed to obtain the irregularly shaped patches. To synthesize strictly structured textures, a regular pasting method is proposed to identify the texture structures and subsequently position the irregularly shaped patches according to the identified structures. The results and comparisons with related work are given.