EG2007

Permanent URI for this community

https://diglib.eg.org/handle/10.2312/258

Browse

Now showing 1 - 20 of 74

Haptic Simulation, Perception and Manipulation of Deformable Objects
(The Eurographics Association, 2007) Magnenat-Thalmann, Nadia; Volino, Pascal; Bonanni, Ugo; Summers, Ian R.; Brady, A. C.; Qu, J.; Allerkamp, D.; Fontana, M.; Tarri, F.; Salsedo, F.; Bergamasco, Massimo; Karol Myszkowski and Vlastimil Havran
This tutorial addresses haptic simulation, perception and manipulation of complex deformable objects in virtual environments (VE). We first introduce HAPTEX, a research project dealing with haptic simulation and perception of textiles in VEs. Then, we present state-of-the-art techniques concerning haptic simulation and rendering, ranging from physically based modelling to control issues of tactile arrays and force-feedback devices. In the section on cloth simulation for haptic systems we describe techniques for simulating textiles adapted to the specific context of haptic applications. The section concerning tactile aspects of virtual objects shows how arrays of contactors on the skin can be used to provide appropriate spatiotemporal patterns of mechanical excitation to the underlying mechanoreceptors. Finally, the last section addresses the problem of developing suitable force feedback technologies for the realistic haptic rendering of the physical interaction with deformable objects, addressing the design of novel force feedback systems, innovative concepts for curvature simulation and control algorithms for accuracy improvement.
Inverse Kinematics and Kinetics for Virtual Humanoids
(The Eurographics Association, 2007) Boulic, Ronan; Kulpa, Richard; Karol Myszkowski and Vlastimil Havran
The present tutorial deals with the use of inverse kinematics and kinetics for postural adaptations of virtual hu- manoids to different kind of constraints. It first proposes an overview of the problematic of this thematic and then of the existing techniques. Then it technically describes two key approaches: the prioritized inverse kinematics for accurate and realistic adaptation and a CCD-like algorithm based on groups for fast and realistic adaptation of hundreds of characters in real-time.
Capturing Reflectance - From Theory to Practice
(The Eurographics Association, 2007) Lensch, Hendrik P. A.; Goesele, Michael; M¨uller, Gero; Karol Myszkowski and Vlastimil Havran
One important problem in photorealistic or predictive rendering nowadays is to realistically model the light interaction with objects. Measurements can capture the reflection properties of real world surface, i.e., they are one way of obtaining realistic reflection properties. For arbitrary (non-fluorescent, non-phosphorescent) materials, the reflection properties can be described by the 8D reflectance field of the surface, also called BSSRDF. Since densely sampling an 8D function is currently not practical various acquisition methods have been proposed which reduce the number of dimensions by restricting the viewing or relighting capabilities of the captured data sets. In this tutorial we will mainly focus on three different approaches, the first allowing to reconstruct opaque surfaces from a very small set of input images, the second allows for arbitrary surfaces but under the assumption of distant light sources and the last which allows for relighting an arbitrary scene with arbitrary spatially varying light patterns. After a short introduction explaining some fundamental concepts regarding measuring and representing reflection properties, the basics of data acquisition with photographs will be addressed. The tutorial present the set of current state-of-the art algorithms for acquiring and modeling 3D objects. The tutorial investigates the strengths and limitations of each technique and sorts them by their complexity with regard to acquisition costs. Besides describing the theoretical contributions we will furthermore point out the practical issues when acquiring reflectance fields in order to help interested users to build and implement their own acquisition setup.
Visualization of Multi-variate Scientific Data
(The Eurographics Association, 2007) Bürger, Raphael; Hauser, Helwig; Dieter Schmalstieg and Jiri Bittner
In this state-of-the-art report we discuss relevant research works related to the visualization of complex, multivariate data. We focus on non-classical approaches, i.e. approaches which haven t been discussed in previous related reports, and we highlight techniques which potentially lead towards new directions in visualization research. We discuss how different techniques take effect at specific stages of the visualization pipeline and how they apply to multi-variate data sets being composed of scalars, vectors, and tensors. We also provide a categorization of these techniques in the aim for a better overview of related approaches. In the second part of this paper we take a look at recent techniques that are useful for the visualization of complex data sets either because they are general purpose or because they can be adapted to specific problems.
Virtual Agent Navigation in Open Spaces using Iterative Shrinking Polygons
(The Eurographics Association, 2007) Haciomeroglu, Murat; Laycock, Robert; Day, Andy; Paolo Cignoni and Jiri Sochor
Populating an urban environment with a virtual crowd provides a dynamic element to an otherwise static scene; bringing the virtual environment to life. One of the fundamental components governing the fidelity of the scene is the realistic simulation of the crowd behaviour. To create a believable crowd simulation one group of methods considers constructing a graph covering the space available to the virtual agents and subsequently performing path planning to allow the agents to navigate their environment by traversing the edges of the graph. To avoid computationally expensive path planning algorithms there exists a tradeoff between the number of edges in the graph and the amount of available space which an agent can visit. In order to alleviate this problem we propose to compute the straight skeleton to provide an initial covering of the environment. This is subsequently augmented using iterative shrinking polygons to generate additional edges in the larger open spaces. The technique developed requires limited knowledge of the urban environment, processes the relevant information automatically and is illustrated in this paper to control the behaviour of a virtual crowd in real time.
Report of the CGE 06 Computer Graphics Education Workshop, Vienna, Austria, September 9, 2006
(The Eurographics Association, 2007) Bourdin, Jean-Jacques; Cunningham, Steve; Fairn, Marta; Hansmann, Werner; Isabel Navazo and Petr Felkel
In order to include computer graphics in European university programme programmes in computer science, the computer graphics curriculum must be organised along lines that satisfy the Bologna requirements for cross cross-university transfers. This workshop suggests ways to organise courses so that a computer graphics programme can be as comprehensive in its scope as fits any particular university, have its curriculum be easily understood by others, and allow simple transferring into and out of its programme. The structure developed by this workshop is still in ou outline form, but it serves as a tline framework from which actual courses and textbooks can be developed to fill out a comprehensive Bachelors and Masters computer graphics curriculum.
Bridging Semantic Web and Digital Shapes
(The Eurographics Association, 2007) Papaleo, Laura; Floriani, Leila De; Hendler, Jim; Paolo Cignoni and Jiri Sochor
Since the volume of multimedia content available on the Web is continuously increasing, a clear need for advanced techniques capable of performing an effective retrieval and management of such data. In this context, in order to reason on digital shapes and their associated semantic, we see a growing interest in exploiting the potential of the Semantic Web in different research fields. We present here the design and initial development of our new system, that we call be-SMART for inspecting digital 3D shapes by extracting geometrical and topological information from them and for structuring and annotating these shapes using ontology-driven metadata. We describe the general structure of the system, its modules and their mutual relations. We also provide motivations for further work in developing new techniques for managing 3D models on the Web.
Mapping highly detailed color information on extremely dense 3D models: the case of David s restoration
(The Eurographics Association, 2007) Dellepiane, Matteo; Callieri, Marco; Ponchio, Federico; Scopigno, Roberto; David B. Arnold and Andrej Ferko
The support of advanced Information Technology (IT) to preservation, restoration and documentation of Cultural Heritage is becoming a very important goal for the research community. Michelangelo's David was one of the first applications of 3D scanning technology on a highly popular work of art. The subsequent restoration campaign, started in 2002 and concluded in 2004, was also a milestone for the adoption of modern scientific analysis procedures and IT tools in the framework of a restoration process. One of the focuses in this restoration was also methodological, i.e. to plan and adopt innovative ways to document the restoration process. In this paper we present the results of an integration of different restoration data (2D and 3D datasets) which has been concluded recently. The recent evolution of HW and SW graphics technologies gave us the possibility to interactively visualize an extremely dense 3D model which incorporates the color information provided by two professional photographic campaigns, made before and after the restoration. Moreover, we present the results concerning the mapping, in this case on the 2D media, of the reliefs produced by restorers to assess and document the status of the marble surface before the restoration took place. This result could lead to new and fascinating applications of computer graphics for preservation, restoration and documentation of Cultural Heritage.
New Trends in 3D Video
(The Eurographics Association, 2007) Theobalt, Christian; Würmlin, Stephan; Aguiar, Edilson de; Niederberger, Christoph; Karol Myszkowski and Vlastimil Havran
3D Video is an emerging and challenging research discipline that lives on the boundary between computer vision and computer graphics. The goal of researchers working in the field is to extract spatio-temporal models of dynamic scenes from multi-video footage in order to display them from user-controlled synthetic perspectives. 3D Video technology has the potential to lay the algorithmic foundations for a variety of intriguing new applications. This includes stunning novel visual effects for movies and computer games, as well as, facilitating the entire movie production pipeline by enabling virtual rearranging of cameras and lighting during post-processing. Furthermore, 3D Video processing will revolutionize visual media by enabling 3D TV and movies with interactive viewpoint control, or by enabling virtual fly-arounds during sports-broadcasts. To achieve this purpose, several challenging problems from vision and graphics have to be solved simultaneously. The speakers in this course will explain the foundations of dynamic scene acquisition, dynamic scene reconstruction and dynamic scene rendering based on their own seminal work, as well as related approaches from the literature. They will explain in more detail three important categories of algorithms for dynamic shape and appearance reconstruction, namely silhouette-based, stereobased, and model- based approaches. Alternative methods, such as data-driven approaches, will also be reviewed. The tutorial will focus on latest 3D Video techniques that were not yet covered in a tutorial, including algorithms for freeviewpoint video relighting, model-based deformable mesh tracking, as well as highquality scene reconstruction with camera/projector setups. The course keeps a balance between the explanation of theoretical foundations, engineering problems and emerging applications of 3D Video technology. We therefore believe that the course will be a valuable and entertaining source of information for students, researchers and practitioners alike.
State-of-the-Art Computer Graphics in Neurosurgical Planning and Risk Assessment
(The Eurographics Association, 2007) Köhn, Alexander; Weiler, Florian; Klein, Jan; Konrad, Olaf; Hahn, Horst; Peitgen, Heinz-Otto; Paolo Cignoni and Jiri Sochor
We present a novel software assistant that unlocks new potentials in neurosurgical planning and risk assessment. It allows surgeons to approach the task in an intuitive manner, by providing them with the possibility to simultaneously observe all relevant data of a case in synchronized 2D and 3D views. State-of-the-art technologies from the field of computer graphics are combined to allow simultaneous interactive rendering of anatomical and functional MR data in combination with manually segmented objects and slice-based overlays. This allows surgeons to perceive a clearer impression of the anatomical and functional structures affected by an intervention, and especially the way they are related to each other. Thus, it significantly facilitates the finding of an optimal intervention strategy.
View-based Shape Similarity using Mutual Information Spheres
(The Eurographics Association, 2007) García, Francisco González; Feixas, Miquel; Sbert, Mateu; Paolo Cignoni and Jiri Sochor
We present a new method for computing the shape similarity between 3D polygonal models using an informationtheoretic viewpoint selection framework. Given a 3D model, a sphere of viewpoints surrounding this model is used to obtain its shape signature from the mutual information of each viewpoint. This signature represents the essence of the shape from a view-based approach. Then, in order to quantify the dissimilarity between two models, their mutual information spheres are registered by minimizing the L2 distance between them. Several experiments show the discrimination capabilities of our approach and its potential suitability for object recognition.
An Interactive Exploration of the Virtual Stronghold Dillenburg
(The Eurographics Association, 2007) Todt, Severin; Rezk-Salama, Christof; Horz, T.; Pritzkau, Andrew; Kolb, Andreas; David B. Arnold and Andrej Ferko
This paper presents the results of an interdisciplinary project aiming at the virtual three-dimensional reconstruction of the stronghold Dillenburg, which has been completely destroyed in 1768. For an interactive virtual exploration, a high-quality 3D model was generated in close cooperation between local historians and scientists from the field of Computer Graphics based on a collection of ancient text documents, drawings and floor plans. Computer animations were generated and assembled in a DVD product for comfortable access to the virtual fortress. For the exhibition in the museum Dillenburg, a real-time application was developed for on site virtual exploration. Provided with a touch screen for interaction and a wide-screen display system, visitors can intuitively explore the virtual reconstruction and access supplemental historical background material on demand. With the multimedia installation we present a new experience which empowers visitors of the museum to explore an historical site freely at their own preferences and encourages younger audience to show more interest in cultural heritage.
The Arnolfini Portrait in 3D - Creating Virtual World of a Painting with Inconsistent Perspective
(The Eurographics Association, 2007) Jansen, Philip H.; Ruttkay, Zsofia M.; David B. Arnold and Andrej Ferko
We report on creating a 3d virtual reconstruction of the scene shown in "The Arnolfini Portrait" by Jan van Eyck. This early Renaissance painting, if painted faithfully, should confirm to one-point perspective, however it has several vanishing points instead of one. Hence our 3d reconstruction had to be based on some, from an art historian s point of view plausible assumptions on choosing a unique vanishing point and measures of certain items in the scene. We compare our approach to similar reconstructions by others. Using professional modeling and image processing computer tools, we created a 3d reconstruction of the geometry of the interior, the textures and the lighting. A perspective view of this model is compared to the original painting, showing high fidelity, but at the same time also large local mismatches due to the inconsistent handling of parallel lines in the original painting, as well as some differences in the reflected image in the mirror. A reconstruction such as ours provides new details of the original scene for scholars, is useful for art historians to find out more about the way the painting was created, and could be used as an installation for exploration in museums or other learning environments by the general public.
Preface and Table of Contents
(The Eurographics Association, 2007) -; Isabel Navazo and Petr Felkel
Preface and Table of Contents
Volumetric Normal Mapping in Rendering of Multivariate Volume Data
(The Eurographics Association, 2007) Seipel, Stefan; Paolo Cignoni and Jiri Sochor
The work presented in this paper introduces volumetric normal maps for producing visual structure in direct volume rendering (DVR) of 3D data for the purpose of visualizing multiple attributes in a 3D volume. We use volumetric normal maps to represent normal vector glyphs that are subsequently applied to warp the gradients in the primary volume data. This method is intended to visualize some secondary attribute in DVR. We demonstrate that our method can render visual structures in DVR without the need of explicit surface reconstruction and texturing.
Color Pages
(The Eurographics Association, 2007) Arnold, David B.; Ferko, Andrej; David B. Arnold and Andrej Ferko
Color Pages
A Unified Interpolatory and Approximation sqrt-3 Subdivision Scheme
(The Eurographics Association, 2007) Lin, Shujin; Luo, Xiaonan; Paolo Cignoni and Jiri Sochor
We have found that there is a relationship between the cubic B-spline and four-point curve subdivision method. In the paper it is used to deduce interpolatory subdivision schemes from cubic B-spline based approximation subdivision schemes directly and construct unified schemes for compositing approximation and interpolatory subdivision. A new interpolatory p3 subdivision scheme and a interpolatory and approximation blended p3 subdivision scheme are created by this straightforward method. The former produces C1 limit surface and avoids the problem in the exsiting interpolatory p3 subdivision mask where the weight coefficients on extraordinary vertices can not be described by explicit formulation. The latter can be used to solve the "popping effect" problem when switching between meshes at different levels of resolution, provide the possibility to locally choose an interpolating variant of the conventionally approximating subdivision scheme, and give more flexibility for feature modeling. These are realized by only changing the value of a parameter. The method is thoroughly simple without needs of constructing and solving equations.
A Discussion of the CGE06 Workshop Report
(The Eurographics Association, 2007) Cunningham, Moderator: Steve; Isabel Navazo and Petr Felkel
The CGE06 workshop, held after the EG06 conference in Vienna, recommended a structure for first cycle an and second cycle education in computer graphics. The workshop report is online at d http://education.siggraph.org/conferences/eurographics/2006/cge2006. This discussion will present an overview of the recommended structure by four European workshop participa participants. They will present their views on the workshop recommendations and will discuss any nts. steps that have been taken to implement them in their own or in other universities.
3D Shape Description and Matching Based on Properties of Real Functions
(The Eurographics Association, 2007) Biasotti, Silvia; Falcidieno, Bianca; Frosini, Patrizio; Giorgi, Daniela; Landi, Claudia; Marini, Simone; Patané, Giuseppe; Spagnuolo, Michela; Karol Myszkowski and Vlastimil Havran
This tutorial covers a variety of methods for 3D shape matching and retrieval that are characterized by the use of a real-valued function defined on the shape (mapping function) to derive its signature. The methods are discussed following an abstract conceptual framework that distinguishes among the three main components of these class of shape matching methods: shape analysis, via the application of the mapping function, shape description, via the construction of a signature, and comparison, via the definition of a distance measure. Goal of the tutorial is to facilitate the understanding of the performance of the various methods by a methodical analysis of the properties of various methods at the three different stages.
Shape Representations Based on Simplicial and Cell Complexes
(The Eurographics Association, 2007) Floriani, L. De; Hui, A.; Dieter Schmalstieg and Jiri Bittner
Simplicial and cell complexes are the most common way to discretize 3D shapes and two-, three and higherdimensional scalar fields. In this state-of-the-art report, we review, analyze and compare data structures for simplicial and cell complexes. We first classify such representations, based on the dimension of the complexes they can encode, into dimension-independent, and dimension-specific ones. We further classify the data structures in each group according to the basic types of topological entities they represent. We present a description of each data structure in terms of the entities and topological relations it encodes, and we evaluate it based on its expressive power, on its storage cost, on the efficiency in supporting navigation inside the complex (i.e., in retrieving topological relations not explicitly encoded in the data structure). We also discuss a decomposition approach to modeling non-manifold shapes, which has led to powerful and scalable representations.

Browse

Browsing EG2007 by Issue Date

Results Per Page

Sort Options