EG2005

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https://diglib.eg.org/handle/10.2312/247

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High Dynamic Range Techniques in Graphics: from Acquisition to Display
(The Eurographics Association, 2005) Goesele, Michael; Heidrich, Wolfgang; Höfflinger, Bernd; Krawczyk, Grzegorz; Myszkowski, Karol; Trentacoste, Matthew; Ming Lin and Celine Loscos
This course is motivated by tremendous progress in the development and accessibility of high dynamic range technology (HDR) that happened just recently, which creates many interesting opportunities and challenges in graphics. The course presents a complete pipeline for HDR image and video processing from acquisition, through compression and quality evaluation, to display. Also, successful examples of the use of HDR technology in research setups and industrial applications are provided. Whenever needed relevant background information on human perception is given which enables better understanding of the design choices behind the discussed algorithms and HDR equipment.
Multimodal Interfaces: an Introduction to ENACTIVE systems
(The Eurographics Association, 2005) Bergamasco, Massimo; Ming Lin and Celine Loscos
Enactive Interfaces are related to a fundamental "interaction" concept which is not exploited by most of the existing human-computer interface technologies. The traditional interaction with the information mediated by a computer is mostly based on symbolic or iconic knowledge, and not on enactive knowledge. While in the symbolic way of learning knowledge is stored as words, mathematical symbols or other symbol systems, in the iconic stage knowledge is stored in the form of visual images, such as diagrams and illustrations that can accompany verbal information. On the other hand, enactive knowledge is a form of knowledge based on the active use of the hand for apprehension tasks. Enactive knowledge is not simply multisensory mediated knowledge, but knowledge stored in the form of motor responses and acquired by the act of "doing". A typical example of enactive knowledge is constituted by the competence required by tasks such as typing, driving a car, dancing, playing a musical instrument, modelling objects from clay, which would be difficult to describe in an iconic or symbolic form. This type of knowledge transmission can be considered the most direct, in the sense that it is natural and intuitive, since it is based on the experience and on the perceptual responses to motor acts.
Fast Body-Cloth simulation with moving humanoids
(The Eurographics Association, 2005) Rodriguez-Navarro, Javier; Sainz, Miguel; Susin, Antonio; John Dingliana and Fabio Ganovelli
In this paper we present a very fast method for body-cloth animation. The usual bottle-neck in cloth simulation performance is collision detection, which becomes more difficult to solve when a complex geometry, like a human body, is involved. Recent image based methods, that use depth images to detect collisions, usually relays on CPU for collision correction. In our work we implement a GPU based simulation that takes care both of cloth simulation and body-cloth collisions when the humanoid is moving. Our solution is based on a hierarchic depth map structure. A high frame rate is obtained with both structured and unstructured cloth meshes with thousands of particles.
Function-based Shape Modeling Framework in Multilevel Education
(The Eurographics Association, 2005) Pasko, A.; Adzhiev, V.; Goto, Y.; Vilbrandt, C.; Jean-Jacques Bourdin and Hugh McCabe
We describe how an approach to the development of a shape modeling and visualization framework based on the rapidly progressing function representation can be used in education. The modeling language and software tools are being developed within an international HyperFun Project. We applied the theoretical framework and software tools on different levels of education starting from elementary schools to doctoral thesis research in various areas related to mathematics, computer graphics, programming languages, artistic design and animation. We illustrate the presented approach by the practical experience examples from different educational institutions and countries
A Scalable Hardware and Software System for the Holographic Display of Interactive Graphics Applications
(The Eurographics Association, 2005) Balogh, Tibor; Forgács, Tamás; Agács, Tibor; Balet, Olivier; Bouvier, Eric; Bettio, Fabio; Gobbetti, Enrico; Zanetti, Gianluigi; John Dingliana and Fabio Ganovelli
We present a scalable holographic system design targeting multi-user interactive computer graphics applications. The display uses a specially arranged array of micro-displays and a holographic screen. Each point of the holographic screen emits light beams of different color and intensity to the various directions, in a controlled manner. The light beams are generated through a light modulation system arranged in a specific geometry and the holographic screen makes the necessary optical transformation to compose these beams into a perfectly continuous 3D view. With proper software control, the light beams leaving the various pixels can be made to propagate in multiple directions, as if they were emitted from physical objects at fixed spatial locations. The display is driven by DVI streams generated by multiple consumer level graphics boards and decoded in real-time by image processing units that feed the optical modules at high refresh rates. An OpenGL compliant library running on a client PC redefines the OpenGL behavior to multicast graphics commands to server PCs, where they are re-interpreted for implementing holographic rendering. The feasibility of the approach has been successfully evaluated with a working hardware and software 7.4M pixel prototype driven at 10-15Hz by three DVI streams.
Rendering Realistic Trees and Forests in Real Time
(The Eurographics Association, 2005) Candussi, Alberto; Canduss, Nicola; Höllerer, Tobias; John Dingliana and Fabio Ganovelli
Real-Time rendering of realistic trees on common graphics hardware represents a big challenge due to their inherent geometric complexity. In most cases, trees are composed of hundreds of thousands of leaves and branches with complex lighting interrelations. We present novel techniques to render and animate photorealistic trees in real-time. The described techniques are easily implemented with commonly available graphics cards, making them suitable to applications such as visual simulations and video games. Polygon counts are significantly reduced by the use of simplified textured geometry for minor branches and billboarded leaf textures. Fast and realistic lighting and shadowing of the leaves and surroundings enhances realism. We animate the tree branches and leaf textures using simple vertex shaders, creating a realistic effect of the tree swaying in the wind. Discrete levels of detail allow rendering of a large number of trees, making it possible to represent realistic forest scenes made of 1000-1500 trees.
A 3D Perceptual Metric using Just-Noticeable-Difference
(The Eurographics Association, 2005) Cheng, Irene; Boulanger, Pierre; John Dingliana and Fabio Ganovelli
In multimedia applications, it is essential to distribute resources efficiently among different types of data in order to optimize overall quality. We propose a perceptual metric using Just-Noticeable-Difference (JND) to identify redundant mesh data so that available bandwidth can be allocated to improve texture resolution. Evaluation of perceptual impact during runtime is based on statistics in a lookup table generated during preprocessing. If the impact is less than the JND, no mesh refinement is performed. We apply Weber s fraction to compute the JND threshold, which is verified by perceptual evaluations. Experimental result shows that our JND model can accurately predict perceptual impact based on the human visual system.
A Survey of General-Purpose Computation on Graphics Hardware
(The Eurographics Association, 2005) Owens, John D.; Luebke, David; Govindaraju, Naga; Harris, Mark; Krüger, Jens; Lefohn, Aaron E.; Purcell, Timothy J.; Yiorgos Chrysanthou and Marcus Magnor
The rapid increase in the performance of graphics hardware, coupled with recent improvements in its programmability, have made graphics hardware a compelling platform for computationally demanding tasks in a wide variety of application domains. In this report, we describe, summarize, and analyze the latest research in mapping general-purpose computation to graphics hardware. We begin with the technical motivations that underlie general-purpose computation on graphics processors (GPGPU) and describe the hardware and software developments that have led to the recent interest in this field. We then aim the main body of this report at two separate audiences. First, we describe the techniques used in mapping general-purpose computation to graphics hardware. We believe these techniques will be generally useful for researchers who plan to develop the next generation of GPGPU algorithms and techniques. Second, we survey and categorize the latest developments in general-purpose application development on graphics hardware. This survey should be of particular interest to researchers who are interested in using the latest GPGPU applications in their systems of interest.
Video Textures Exploiting Symmetric Movements
(The Eurographics Association, 2005) Haevre, William Van; Reeth, Frank Van; John Dingliana and Fabio Ganovelli
In this paper, an extension to the traditional method for creating video textures is presented. By exploiting the symmetric properties of the frames in a given video sequence, a new endless video stream or video loop is generated by reversing video playback when appropriate. We aim at a larger set of possible input video's for video texture creation, including captured motions containing no smooth transitions (eg. turbulent plant movements). To achieve this, good turn points, instead of transitions are extracted from the video data, after which a simple algorithm synthesizes a new video sequence while optimally exploiting the original frame data. Visual artifacts caused by changed lighting conditions are reduced significantly.
Fast and Controllable 3D Modelling From Silhouettes
(The Eurographics Association, 2005) Prasad, Mukta; Fitzgibbon, Andrew; Zisserman, Andrew; John Dingliana and Fabio Ganovelli
We show how a 3D model of a complex curved object can be easily extracted from a single 2D image. A userdefined silhouette is the key input; and we show that finding the smoothest 3D surface which projects exactly to this silhouette can be expressed as a quadratic optimization, a result which has not previously appeared in the large literature on the shape-from-silhouette problem. For simple models, this process can immediately yield a usable 3D model; but for more complex geometries the user will wish to further shape the surface. We show that a variety of editing operations which can be defined either in the image or in 3D can also be expressed as linear constraints on the 3D shape parameters. We extend the system to fit higher genus surfaces. Our method has several advantages over the system of Zhang et al. [ZDPSS01] and over systems such as SKETCH and Teddy.
Interaction in Distributed Virtual Environments
(The Eurographics Association, 2005) Glencross, Mashhuda; Otaduy, Miguel; Chalmers, Alan; Ming Lin and Celine Loscos
This course will describe the main challenges faced when building engaging shared virtual environments supporting complex behaviour and interaction, and provide discussions on techniques that can be adopted to support some of these. In order to build such environments, it is necessary to combine high quality graphics, better modes of interaction, rich behavioural simulations and appropriate distribution strategies. After introducing the field of interaction and rich behaviour in collaborative virtual environments, we cover the main issues in three parts. First we look at techniques for improving the user s experience by using high-fidelity graphical rendering, and explore how this may be achieved in real-time through exploitation of features of the human visual perception system. We examine also how additional sensory modalities such as audio and haptic rendering may further improve this experience. Second we consider issues of distribution with an emphasis on avoiding potential pitfalls when distributing complex simulations together with an analysis of real network conditions, and the implications of these for distribution architectures that provide for shared haptic interaction. Finally we present the current state of the art of haptic interaction techniques. In particular the motivations for perceptually-inspired force models for haptic texture rendering, interaction between such models and GPU techniques for fast haptic texture rendering. The objective of this course is to give an introduction to the issues to consider when building highly engaging interactive shared virtual environments, and techniques to mediate complex haptic interaction with sophisticated 3D environments.
Visual Learning for Science and Engineering
(The Eurographics Association, 2005) Brown, Judith R.; Cunningham, Steve; Hansmann, Werner; McGrath, Michael B.; Jean-Jacques Bourdin and Hugh McCabe
Visual Learning is the use of graphics, images and animations to enable and enhance learning. <br>The goal of this study is to make faculty in science, computer science, and engineering disciplines aware of the potential for learning through visual means and to encourage them to use visual methods for teaching. Exploiting the visual senses of students can engage their interests and enhance learning. These active visual methods have the potential to increase the number of students, especially women and minorities.
Facial Motion Cloning Using Global Shape Deformation
(The Eurographics Association, 2005) Fratarcangeli, Marco; Schaerf, Marco; John Dingliana and Fabio Ganovelli
We present a novel Facial Motion Cloning method relying on the combination of the radial basis functions (RBF) based scattered data interpolation with the encoding capabilities of the MPEG-4 Facial and Body Animation (FBA) international standard. Beside from an initial manual selection of feature points, our method works fully automatically without user interaction. The produced talking head is able to perform generic face animation which is stored in a MPEG-4 FBA data stream.
Illustrative Visualization
(The Eurographics Association, 2005) Viola, Ivan; Gröller, Meister E.; Hadwiger, Markus; Bühler, Katja; Preim, Bernhard; Ebert, David; Ming Lin and Celine Loscos
The tutorial presents state-of-the-art visualization techniques inspired by traditional technical and medical illustrations. Such techniques exploit the perception of the human visual system and provide effective visual abstractions to make the visualization clearly understandable. Visual emphasis and abstraction has been used for expressive presentation from prehistoric paintings to nowadays scientific and medical illustrations. Many of the expressive techniques used in art are adopted in computer graphics, and are denoted as illustrative or non-photorealistic rendering. Different stroke techniques, or brush properties express a particular level of abstraction. Feature emphasis or feature suppression is achieved by combining different abstraction levels in illustrative rendering. Challenges in visualization research are very large data visualization as well as multi-dimensional data visualization. To effectively convey the most important visual information there is a significant need for visual abstraction. For less relevant information the dedicated image space is reduced to enhance more prominent features. The discussed techniques in the context of scientific visualization are based on iso-surfaces and volume rendering. Apart from visual abstraction, i.e., illustrative representation, the visibility of prominent features can be achieved by illustrative visualization techniques such as cut-away views or ghosted views. The structures that occlude the most prominent information are suppressed in order to clearly see more interesting parts. Another smart way to provide information on the data is using exploded views or other types of deformation. Illustrative visualization is demonstrated via application-specific tasks in medical visualization. An important aspect as compared to traditional medical illustrations is the interactivity and real-time manipulation of the acquired patient data. This can be very useful in anatomy education. Another application area is surgical planning which is demonstrated with two case studies: neck dissection and liver surgery planning.
Using 3D Graphics for Learning and Collaborating Online
(The Eurographics Association, 2005) Monahan, T.; McArdle, G.; Bertolotto, M.; Jean-Jacques Bourdin and Hugh McCabe
Today, the use of e-learning is common place. E-learning courses are now becoming prevalent on the Internet. They offer students great flexibility as well as a wide range of subjects. Traditionally the majority of these courses provide learners with text-based material and allow them to contact the course tutor via email. Virtual Reality (VR) has a lot to offer the e-learning paradigm. 3D virtual worlds can give people a sense of belonging and, as they mimic the real world, they are a natural way to access information. This paper describes CLEV-R, a collaborative learning environment with Virtual Reality. This environment uses VR and multimedia to deliver learning material to students in a stimulating and motivating manner. By using a suite of communication tools, students can learn, collaborate and socialise on line.
A Sharpness Dependent Approach to 3D Polygon Mesh Hole Filling
(The Eurographics Association, 2005) Chen, Chun-Yen; Cheng, Kuo-Young; Liao, H.Y. Mark; John Dingliana and Fabio Ganovelli
A sharpness dependent hole filling approach is proposed in this paper. The proposed method can fill the hole of a mesh-based model and recover its sharp feature located at the hole area. Interpolation based on radial basis function is applied to create a smooth implicit surface and this surface can approximate the shape of the missed data. Then, a regularized marching tetrahedral algorithm is adopted to triangulate the above implicit surface and to produce a polygonal hole patch. A repaired mesh model is obtained by stitching the hole patch and the hole boundary of the original model. Finally, a feature enhancement process is applied if there exists a sharp feature on the hole boundary of the original model. The introduction of a sharpness dependent filter enhances the sharp feature of a hole-filled model. Experiment results show that our approach can produce excellent reparation results especially for recovering sharp feature.
Leaf Cluster Impostors for Tree Rendering with Parallax
(The Eurographics Association, 2005) Garcia, Ismael; Sbert, Mateu; Szirmay-Kalos, László; John Dingliana and Fabio Ganovelli
This paper presents a simple method to render complex trees on high frame rates while maintaining parallax effects. Based on the recognition that a planar impostor is accurate if the represented polygon is in its plane, we find an impostor for each of those groups of tree leaves that lie approximately in the same plane. The groups are built automatically by a clustering algorithm. Unlike billboards, these impostors are not rotated when the camera moves, thus the expected parallax effects are provided. On the other hand, clustering allows the replacement of a large number of leaves by a single semi-transparent quadrilateral, which improves rendering time considerably. Our impostors well represent the tree from any direction and provide accurate depth values, thus the method is also good for shadow computation.
Preface
(The Eurographics Association, 2005) -; Jean-Jacques Bourdin and Hugh McCabe
Preface and Table of Contents
Estimating Mobile Memory Requirements and Rendering Time for Remote Execution of the Graphics Pipeline
(The Eurographics Association, 2005) Banerjee, Kutty; Wu, Fan; Agu, Emmanuel; John Dingliana and Fabio Ganovelli
Mobile devices have limited processing power, memory and battery power. Remote execution, wherein part or entire graphics pipeline is offloaded to a powerful surrogate server, is an attractive solution for low end mobile devices such as PDAs and cell phones that lack floating point units or GPUs. We have found that remote execution of floating-point-intensive pipeline stages such as transform and geometry operations can produce speedups of up to 10 times for a low-end mobile device. We introduce generalized pipeline-splitting, a paradigm whereby 15 sub-stages of the graphics pipeline are instrumented with networking code such that they can run either on a mobile client or a surrogate server. To validate our concepts, we create Remote Mesa (RMesa). As a foundation for deciding which stages of the pipeline would benefit from remote execution, this paper presents analytical models for the overall rendering time, memory requirements and roundtrip network delay incurred by RMesa.
Key Techniques for interactive Virtual Garment Simulation
(The Eurographics Association, 2005) Volino, Pascal; Magnenat-Thalmann, Nadia; Thomaszewski, Bernhard; Wacker, Markus; Ming Lin and Celine Loscos
Virtual garment design and simulation involves a combination of a large range of techniques, involving mechanical simulation, collision detection, and user interface techniques for creating garments. Here, we perform an extensive review of the evolution of these techniques made in the last decade to bring virtual garments to the reach of computer applications not only aimed at graphics, but also at CAD techniques for the garment industry.

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