Volume 26 (2007)

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https://diglib.eg.org/handle/10.2312/128

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3D Lip-Synch Generation with Data-Faithful Machine Learning
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Kim, Ig-Jae; Ko, Hyeong-Seok
This paper proposes a new technique for generating three-dimensional speech animation. The proposed technique takes advantage of both data-driven and machine learning approaches. It seeks to utilize the most relevant part of the captured utterances for the synthesis of input phoneme sequences. If highly relevant data are missing or lacking, then it utilizes less relevant (but more abundant) data and relies more heavily on machine learning for the lip-synch generation. This hybrid approach produces results that are more faithful to real data than conventional machine learning approaches, while being better able to handle incompleteness or redundancy in the database than conventional data-driven approaches. Experimental results, obtained by applying the proposed technique to the utterance of various words and phrases, show that (1) the proposed technique generates lip-synchs of different qualities depending on the availability of the data, and (2) the new technique produces more realistic results than conventional machine learning approaches.
Layered Performance Animation with Correlation Maps
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Neff, Michael; Albrecht, Irene; Seidel, Hans-Peter
Performance has a spontaneity and aliveness that can be difficult to capture in more methodical animation processes such as keyframing. Access to performance animation has traditionally been limited to either low degree of freedom characters or required expensive hardware. We present a performance-based animation system for humanoid characters that requires no special hardware, relying only on mouse and keyboard input. We deal with the problem of controlling such a high degree of freedom model with low degree of freedom input through the use of correlation maps which employ 2D mouse input to modify a set of expressively relevant character parameters. Control can be continuously varied by rapidly switching between these maps. We present flexible techniques for varying and combining these maps and a simple process for defining them. The tool is highly configurable, presenting suitable defaults for novices and supporting a high degree of customization and control for experts. Animation can be recorded on a single pass, or multiple layers can be used to increase detail. Results from a user study indicate that novices are able to produce reasonable animations within their first hour of using the system. We also show more complicated results for walking and a standing character that gestures and dances.
Interactive Simulation of the Human Eye Depth of Field and Its Correction by Spectacle Lenses
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Kakimoto, Masanori; Tatsukawa, Tomoaki; Mukai, Yukiteru; Nishita, Tomoyuki
This paper describes a fast rendering algorithm for verification of spectacle lens design. Our method simulates refraction corrections of astigmatism as well as myopia or presbyopia. Refraction and defocus are the main issues in the simulation. For refraction, our proposed method uses per-vertex basis ray tracing which warps the environment map and produces a real-time refracted image which is subjectively as good as ray tracing. Conventional defocus simulation was previously done by distribution ray tracing and a real-time solution was impossible. We introduce the concept of a blur field, which we use to displace every vertex according to its position. The blurring information is precomputed as a set of field values distributed to voxels which are formed by evenly subdividing the perspective projected space. The field values can be determined by tracing a wavefront from each voxel through the lens and the eye, and by evaluating the spread of light at the retina considering the best human accommodation effort. The blur field is stored as texture data and referred to by the vertex shader that displaces each vertex. With an interactive frame rate, blending the multiple rendering results produces a blurred image comparable to distribution ray tracing output.
Accurate Depth of Field Simulation in Real Time
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Zhou, Tianshu; Chen, Jim X.; Pullen, Mark
We present a new post processing method of simulating depth of field based on accurate calculations of circles of confusion. Compared to previous work, our method derives actual scene depth information directly from the existing depth buffer, requires no specialized rendering passes, and allows easy integration into existing rendering applications. Our implementation uses an adaptive, two-pass filter, producing a high quality depth of field effect that can be executed entirely on the GPU, taking advantage of the parallelism of modern graphics cards and permitting real time performance when applied to large numbers of pixels.
Real-time homogenous translucent material editing
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Xu, Kun; Gao, Yue; Li, Yong; Ju, Tao; Hu, Shi-Min
This paper presents a novel method for real-time homogenous translucent material editing under fixed illumination. We consider the complete analytic BSSRDF model proposed by Jensen et al. [JMLH01], including both multiple scattering and single scattering. Our method allows the user to adjust the analytic parameters of BSSRDF and provides high-quality, real-time rendering feedback. Inspired by recently developed Precomputed Radiance Transfer (PRT) techniques, we approximate both the multiple scattering diffuse reflectance function and the single scattering exponential attenuation function in the analytic model using basis functions, so that re-computing the outgoing radiance at each vertex as parameters change reduces to simple dot products. In addition, using a non-uniform piecewise polynomial basis, we are able to achieve smaller approximation error than using bases adopted in previous PRT-based works, such as spherical harmonics and wavelets. Using hardware acceleration, we demonstrate that our system generates images comparable to [JMLH01]at real-time frame-rates.
REPORT OF THE STATUTORY AUDITORS TO THE GENERAL MEETING OF THE MEMBERS OF EUROGRAPHICS ASSOCIATION GENEVA
(The Eurographics Association and Blackwell Publishing Ltd, 2007)
EUROGRAPHICS 2006 4 - 8 September, 2006 Vienna, Austria
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Purgathofer, Werner
ShaderX by Wolfgang Engel
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Callieri, M.
Teaching, Exploring, Learning-Developing Tutorials for In-Class Teaching and Self-Learning
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Beckhaus, S.; Blom, K. J.
This paper presents an experience report on a novel approach for a course on intermediate and advanced computer graphics topics. The approach uses Teachlet Tutorials, a combination of traditional seminar-type teaching with interactive exploration of the content by the audience, plus development of self-contained tutorials on the topic. In addition to a presentation, an interactive software tool is developed by the students to assist the audience in learning and exploring the topic s details. This process is guided through set tasks. The resulting course material is developed for two different contexts: (a) for classroom presentation and (b) as an interactive, self-contained, self-learning tutorial. The overall approach results in a more thorough understanding of the topic both for the student teachers as well as for the class participants. In addition to detailing the Teachlet Tutorial approach, this paper presents our experiences implementing the approach in our Advanced Computer Graphics course and presents the resultant projects. Most of the final Teachlet Tutorials were surprisingly good and we had excellent feedback from the students on the approach and course.
A Survey of Haptic Rendering Techniques
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Laycock, S.D.; Day, A.M.
Computer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human s sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment.
Siggraph 2006 Boston, Massachusetts, 30th July-3rd August 2006
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Laycock, R.G.; Laycock, S.D.; Ryder, G.; Day, A.M.
Distance-Ranked Connectivity Compression of Triangle Meshes
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Marais, P.; Gain, J.; Shreiner, D.
We present a new, single-rate method for compressing the connectivity information of a connected 2-manifold triangle mesh with or without boundary. Traditional compression schemes interleave geometry and connectivity coding, and are thus typically unable to utilize information from vertices (mesh regions) they have not yet processed. With the advent of competitive point cloud compression schemes, it has become feasible to develop separate connectivity encoding schemes that can exploit complete, global vertex position information to improve performance.Our scheme demonstrates the utility of this separation of vertex and connectivity coding. By traversing the mesh edges in a consistent fashion, and using global vertex information, we can predict the position of the vertex that completes the unprocessed triangle attached to a given edge. We then rank the vertices in the neighborhood of this predicted position by their Euclidean distance. The distance rank of the correct closing vertex is stored. Typically, these rank values are small, and the set of rank values thus possesses low entropy and compresses very well. The sequence of rank values is all that is required to represent the mesh connectivity-no special split or merge codes are necessary.Results indicate improvements over traditional valence-based schemes for more regular triangulations. Highly irregular triangulations or those containing a large number of slivers are not well modelled by our current set of predictors and may yield poorer connectivity compression rates than those provided by the best valence-based schemes.
Editorial
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Duke, David; Scopigno, Roberto
Precomputed Radiance Transfer Field for Rendering Interreflections in Dynamic Scenes
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Pan, Minghao; Wang Xinguo Liu, Rui; Peng, Qunsheng; Bao, Hujun
In this paper, we introduce a new representation - radiance transfer fields (RTF) - for rendering interreflections in dynamic scenes under low frequency illumination. The RTF describes the radiance transferred by an individual object to its surrounding space as a function of the incident radiance. An important property of RTF is its independence of the scene configuration, enabling interreflection computation in dynamic scenes. Secondly, RTFs naturally fit in with the rendering framework of precomputed shadow fields, incurring negligible cost to add interreflection effects. In addition, RTFs can be used to compute interreflections for both diffuse and glossy objects. We also show that RTF data can be highly compressed by clustered principal component analysis (CPCA), which not only reduces the memory cost but also accelerates rendering. Finally, we present some experimental results demonstrating our techniques.
Omni-directional Relief Impostors
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Andujar, C.; Boo, J.; Brunet, P.; Fairen, M.; Navazo, I.; Vazquez, P.; Vinacua, A.
Relief impostors have been proposed as a compact and high-quality representation for high-frequency detail in 3D models. In this paper we propose an algorithm to represent a complex object through the combination of a reduced set of relief maps. These relief maps can be rendered with very few artifacts and no apparent deformation from any view direction. We present an efficient algorithm to optimize the set of viewing planes supporting the relief maps, and an image-space metric to select a sufficient subset of relief maps for each view direction. Selected maps (typically three) are rendered based on the well-known ray-height-field intersection algorithm implemented on the GPU. We discuss several strategies to merge overlapping relief maps while minimizing sampling artifacts and to reduce extra texture requirements. We show that our representation can maintain the geometry and the silhouette of a large class of complex shapes with no limit in the viewing direction. Since the rendering cost is output sensitive, our representation can be used to build a hierarchical model of a 3D scene.
12th Eurographics Symposium on Virtual Environments
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Hubbold, Roger; Jorge, Joaquim; Lin, Ming
Crowds by Example
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Lerner, Alon; Chrysanthou, Yiorgos; Lischinski, Dani
We present an example-based crowd simulation technique. Most crowd simulation techniques assume that the behavior exhibited by each person in the crowd can be defined by a restricted set of rules. This assumption limits the behavioral complexity of the simulated agents. By learning from real-world examples, our autonomous agents display complex natural behaviors that are often missing in crowd simulations. Examples are created from tracked video segments of real pedestrian crowds. During a simulation, autonomous agents search for examples that closely match the situation that they are facing. Trajectories taken by real people in similar situations, are copied to the simulated agents, resulting in seemingly natural behaviors.
Shape-aware Volume Illustration
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Chen, Wei; Lu, Aidong; Ebert, David S.
We introduce a novel volume illustration technique for regularly sampled volume datasets. The fundamental difference between previous volume illustration algorithms and ours is that our results are shape-aware, as they depend not only on the rendering styles, but also the shape styles. We propose a new data structure that is derived from the input volume and consists of a distance volume and a segmentation volume. The distance volume is used to reconstruct a continuous field around the object boundary, facilitating smooth illustrations of boundaries and silhouettes. The segmentation volume allows us to abstract or remove distracting details and noise, and apply different rendering styles to different objects and components. We also demonstrate how to modify the shape of illustrated objects using a new 2D curve analogy technique. This provides an interactive method for learning shape variations from 2D hand-painted illustrations by drawing several lines. Our experiments on several volume datasets demonstrate that the proposed approach can achieve visually appealing and shape-aware illustrations. The feedback from medical illustrators is quite encouraging.
Geodesic-Controlled Developable Surfaces for Modeling Paper Bending
(The Eurographics Association and Blackwell Publishing Ltd, 2007) Bo, Pengbo; Wang, Wenping
We present a novel and effective method for modeling a developable surface to simulate paper bending in interactive and animation applications. The method exploits the representation of a developable surface as the envelope of rectifying planes of a curve in 3D, which is therefore necessarily a geodesic on the surface. We manipulate the geodesic to provide intuitive shape control for modeling paper bending. Our method ensures a natural continuous isometric deformation from a piece of bent paper to its flat state without any stretching. Test examples show that the new scheme is fast, accurate, and easy to use, thus providing an effective approach to interactive paper bending. We also show how to handle non-convex piecewise smooth developable surfaces.
Boundary Constrained Swept Surfaces for Modelling and Animation
(The Eurographics Association and Blackwell Publishing Ltd, 2007) You, L. H.; Yang, X. S.; Pachulski, M.; Zhang, Jian J.
Due to their simplicity and intuitiveness, swept surfaces are widely used in many surface modelling applications. In this paper, we present a versatile swept surface technique called the boundary constrained swept surfaces. The most distinct feature is its ability to satisfy boundary constraints, including the shape and tangent conditions at the boundaries of a swept surface. This permits significantly varying surfaces to be both modelled and smoothly assembled, leading to the construction of complex objects. The representation, similar to an ordinary swept surface, is analytical in nature and thus it is light in storage cost and numerically very stable to compute. We also introduce a number of useful shape manipulation tools, such as sculpting forces, to deform a surface both locally and globally. In addition to being a complementary method to the mainstream surface modelling and deformation techniques, we have found it very effective in automatically rebuilding existing complex models. Model reconstruction is arguably one of the most laborious and expensive tasks in modelling complex animated characters. We demonstrate how our technique can be used to automate this process.

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