Short Presentations

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https://diglib.eg.org/handle/10.2312/215

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WebTalk: a 3D collaborative environment to access the Web
(Eurographics Association, 1999) Paolini, P.; Barbieri, T.; Loiudice, P.; Alonzo, F.; Arru, M.; Zanti, M.; Gaia, G.
The notion of cooperative visit and interaction within a web site, both at 2D and 3D level, could add decisive motivation to pursue exploitation of the third dimension in networked environments. A prototype developed at the HOC laboratory in Politecnico of Milan, WEBTALK, allows development of custom 3D environments in which actions and situations can be shared throughout a network. The current prototype makes use of standard web-based Internet/Intranet technology: it is composed of a VRML (Virtual Reality Modeling Language) graphical engine and a Java-based TCP/IP (the Internet Protocol) communication layer. The technique has proven itself successful and has given rise to several interesting applications, such as the creation of Virtual 3D Museum Spaces at the National Science Museum (www.museoscienza.org), in which visitors can visit the museum interacting with the exhibits themselves and sharing their experiences with other visitors - even joining a guided tour with the virtual museum guide. A new prototype will make use of a completely Java-based environment, using Sun’s Java 2 and Java 3D. The new WEBTALK will stress even further the issues of third party external authoring of virtual worlds and of cooperation patterns within the shared environments, with a distinction between shared object geometries, shared object behaviors, shared object data (stored in an on-line DBMS), and cooperation metaphors within the virtual world. Linking to 2D-based web sites resources will lead cooperation patterns to be extended also to regular web-space.
Visual Learning with Computer Art Graphics Artwork Description
(Eurographics Association, 1999) Ursyn, Anna
In my work, I use the computer on different levels. For my two-dimensional works, I have been programing in Fortran IV then Fortran 77 using Cyber, then VAX mainframes and Interactive Graphic Library (IGL). I have been setting color combinations, transforming light intensity, applying grid patterns and moir effects in order to gain composition. The two-dimensional programs serve as a point of departure for photolithographs after computer programs and photo silkscreened prints on canvas and paper; they are included both into my two-dimensional and three-dimensional works. Scanners, digital camera and PC/PPCs serve for further image manipulation. All of these approaches are combined for image creation with the use of painterly markings. Printouts have been obtained in several ways: first, black-and white plots from the Versatec plotter and color slides via the Computer Output Microfilmer (COM) recorder, then the Apple, Hewlett-Packard, and Novajet printers/plotters.
Creating light-weight virtual humans for Virtual Environments
(Eurographics Association, 1999) Oliveira, Joao; Buxton, Bernard
With the advent of whole body, 3D electro-optical scanners, a new range of applications are emerging that exploit the availability of personalised, realistic human models. However, realistic rendering of such models usually entails a large number of polygons which can be unacceptable in many applications. We present a framework that exploits the approximate cylindrical and spherical symmetry of human body parts to create light-weight representations that retain the overall dimension of body parts, even at very low polygon counts.
A Rapid Clustering Algorithm for Efficient Rendering
(Eurographics Association, 1999) Müller, Gordon; Schäfer, Stephan; Fellner, Dieter W.
Hierarchical radiosity using object clusters greatly improves rendering times and reduces memory consumption of radiosity computations. The key feature of the algorithm is using a hierarchy of object clusters to approximate the energy exchange between surfaces. The cluster hierarchy used for this purpose however, must accurately reflect the actual scene geometry to justify this approach. Bad clusters easily lead to rendering artifacts. Inspired by the results of our hierarchical bounding volume optimization for ray tracing, we applied the same scheme to a clustering algorithm for hierarchical radiosity. Using an object-oriented framework, the extension of the implementation was straight forward and seems to be promising. Due to the good performance of our hierarchy regarding ray tracing, the same data structure could successfully be used for two things: visibility checks based on ray casting and energy exchange for the radiosity computation. In this short paper, first results regarding our new clustering scheme will be presented. The properties of the underlying bounding volume optimization give reason for interesting applications enhancing various rendering techniques. Some of these new ideas will be discussed here.
Monitoring of the visual arts degrade by means of the active vision system “3EYES”
(Eurographics Association, 1999) Cojoc, D.; Grattoni, P.; Nerino, R.; Pettiti, G.
Monitoring of some physical characteristics (colour, geometry, size of fissures, ...) of object surfaces is of utmost importance in the field of conservation and restoration of work of arts. In order to get effective results a very high repeatability in the localization of the test points is required. At present, repositioning is a tricky task and is performed by means of manual empirical procedures which can be time consuming and expensive. In this short paper an application of the 3EYES active vision system to the automation of the monitoring is presented. An application of the system to object monitoring in laboratory environment is described.
The atrium of St. Mary Abbey in Pomposa: a hypermedial 3-D network database
(Eurographics Association, 1999) Alessandri, Claudio; Gaiani, Marco
The analysis carried out on the atrium of the church of Pomposa is an example of a multidisciplinary experience which gathered historians, computer analysts, structural and computer graphics experts on the same project. A 3-D virtual model and the related data base can be considered a common basis for the different approaches attempted and tools indispensable to a correct representation of the complexities characterizing the atrium.
Interactive Information System for the Camposanto Monumentale of Pisa
(Eurographics Association, 1999) Baracchini, C.; Brogi, A.; Merlitti, D.
Multimedia Database gathering the historical-preservative documentation of the monumental complex, including a digital reconstruction achieved through a solid modelling of the building and its fittings.
A Study of Automatic Program Production Using TVML
(Eurographics Association, 1999) Douke, Mamoru; Makino, Eiji; Hayashi, Masaki
This paper describes a method to create TV programs automatically using TVML(TV program Making Language). TVML is a scripting language that we have developed for generating TV programs by computer. In this paper, we focus on automatic news program creation. We define XML tags for describing contents of a news program, and presentation data for creating the program by given XML file. We have also developed an automatic news program creation software based on the idea.
Contour Extraction of Watermarks in Old Manuscripts
(Eurographics Association, 1999) Wenger, Emanuel; Karnaukhov, Victor N.; Haidinger, Alois
The comparison of watermarks in old paper is the major technique for dating undated medieval manuscripts. The extraction of watermarks as contours is the crucial task in digitalization and building a watermark database. In this paper the method of object delineation by active curves (snakes) is modified and applied to the contour tracing and skeletonization of watermarks.
A Minimalist Approach to Facial Reconstruction
(Eurographics Association, 1999) Gotla, M.; Huang, Z.
We propose a minimalist approach to 3D facial reconstruction. By applying cognitive and anatomical heuristics, we show that a realistic face model can be reconstructed from a generic face model using only one or two real facial images and minimal user interaction.
Animating Brachiation
(Eurographics Association, 1999) Zhang, Zheng; Wong, Kok Cheong
This paper presents a physically-based animation system for generating realistic motion of primate brachiation. One of the main aims of this system is to facilitate the process of generating brachiation sequences with appropriate automaticity and also provide the animator with adequate controllability. A hybrid system based on an integration of three control modules of different levels. The low-level control module, namely forward dynamics interactive module can be employed to rapidly manipulate the torque values at specific joints of a simplied primate figure. Both the mid-level and high-level control modules are designated to automate the process of generating the basic global brachiation movements of the primate figure. The performance of the system is evaluated by measuring the animation results qualitatively and quantitatively. Experimental results have demonstrated the effectiveness and robustness of the paradigm by generating animated sequences of realistic brachiating motion
Registration methods for harmonious integration of real worlds and computer generated objects
(Eurographics Association, 1999) Simon, G.; Lepetit, V.; Berger, M.-O.
This page is an extension of our paper entitled "Registration methods for harmonious integration of real and computer generated objects". We focus in this paper on the problem of adding computer-generated objects in video sequences. We propose a robust method for viewpoint computation which utilizes 3D knowledge on the scene as well as 2D/2D correspondences of key-points. Next, we extend this method to the case of unknown focal length varying from image to image. Finally, we describe how to solve possible occlusions between the computer generated objects and the real scene. Many videos illustrating these different points are presented here.
A Global Routing Mechanism for Modular VRML-Worlds
(Eurographics Association, 1999) Mader, S.
With the increasing complexity of virtual worlds VRML97 reveals its lack of native support for logical modularization of these worlds. Though the inherent mechanisms as PROTO-typing and Inlining allow us to partition our worlds into several files, the restriction to file-limited namespaces makes an event-routing for complex interactions between different modules a rather difficult task. In this paper we present an easy-to-use method for event-based communication across modular VRML scenes. Based on VRML´s event model, this solution goes conform with the VRML97 standard ISO/IEC 14772-1:19971 . In order to show its ability to support the implementation of highly interactive and complex VRML-worlds we demonstrate its application in a current project from the fields of virtual heritage.
Wavelet Projections for Volume Rendering
(Eurographics Association, 1999) Horbelt, Stefan; Unser, Michael; Vetterli, Martin
We extended Gross’s 3 method of volume wavelet rendering by computing splats via an orthogonal projection operator. The method decomposes the volume data into a wavelet pyramid representation in the spline domain. The splats of the basis functions are approximated on a multiresolution grid. Using least-squares approximation ensures the smallest possible error for a given sampling step size. The approximation error on the grid is derived as a function of the sampling step h. The choice of the appropriate wavelet space and spatial resolution at each step produces the smallest possible filters. Our approach reduces the number of computations and allows full control of the image quality.
Gaseous Volume Visualization Using Particle Maps
(Eurographics Association, 1999) Adabala, Neeharika; Manohar, Swami
This paper presents a new method of rendering gaseous volumes using particle maps which store the particles that model the gaseous volume. The particle maps enable quick estimation of densities within a gaseous volume during rendering, analogous to how photon maps enable estimation of radiance during ray tracing. Particle based approaches to model gases are inherently simple and facilitate easy inclusion of physical correctness, but do not generally give realistic images. The alternate of texture based approaches give realistic images but have limited scope for inclusion of physical correctness. We combine these two approaches to give a method that (i) has flexibility to model any gaseous geometry, (ii) offers high scope for incorporation of physical correctness, (iii) does not possess arcane control parameters and (iv) results in realistic images.
Information Technologies for Set-designers
(Eurographics Association, 1999) Silva, C.
The project The set-designer and the instruments of his days–New information technologies for the theatre was proposed in the second edition of the Solomon R. Guggenheim Foundation competition, Impresa & Cultura, Intrapresae Collezione Guggenheim enterprise, being awarded a mention by the jury for the originality of the application in a typical Italian field, the opera theatre, in need of deep innovations. The complete system used for the project consisted of a powerful computer along with specialized software for solid modelling, ALIAS, and a sophisticated program for modifying photographs and image processing used to apply materials to the graphic structure. The author, graduated from the Art Academy of Brera in Milan, was hired to lead the technical part of the project. He had used information technology preparing his exams at the Academy, where he had already realized virtual set-design. On the occasion of the introduced project was trained in the Alias software secrets and he could work closely with the professionals of the Stage setting departments of the theatres involved in the experimental project. At the same time he could finished his studies with a thesis on the use of computer technologies in the theatre.
Adaptive Refinements in Subdivision Surfaces?
(Eurographics Association, 1999) Xu, Zheng; Kondo, Kunio
One problem in subdivision surfaces is the number of meshes grows quickly after every subdivision step. The number of meshes of the subdivision surface is usually huge and the scheme is difficult to manipulate. In this paper, an adaptive refinement method based on Doo-Sabin subdivision surfaces is presented. Adaptation process is controlled by an allowable angle tolerance between the normal vectors of adjacent faces. Local refinements can be realized.
HIT! BAT! IT!
(Eurographics Association, 1999) Maegawa, Hideaki
Today’s high technology is tomorrow’s standard technology. In this rapidly progressing computer graphics world, my goal as designer is to polish and improve on the "old" and well-used skills. This production was originally made as title for my personal video portfolio. Therefore, one of the main criteria was to make it something that could be used for a relatively long time so I took particular care in character motion and camera work, as they are the basic factors of animation.
Virtual Reality and Cultural Heritage Examples: the Mysterious City Fresco, the Domus Aurea
(Eurographics Association, 1999) Cuomo, Massimo; Funto, Fabrizio; Levner, Geoff
Cultural heritage can benefit greatly from the use of virtual reality. Among the demands of cultural heritage that this technology can help to satisfy are the following: Giving laymen the opportunity to appreciate works from the past of which only fragments remain, or which contain cultural references that have been lost over time. Providing researchers with powerful tools. Ensuring the preservation of cultural heritage over risky restoring and degradation due to excessive number of visitor. Making virtual replicas that can be transported without risk to the original, increasing enormously the number of potential visitors. Two examples are presented: The Mysterious City Fresco and The Domus Aurea.
Edinburgh: 200 years of heritage through image-based virtual environments
(Eurographics Association, 1999) Wright, Mark W.; Watson, Gordon; Dunlop, Gair; Middleton, Roy
Heritage is an important application of virtual environments. The key role of virtual environments in this sector is to provide a spatial context for historical records, artifacts and places. This spatial context makes the material more readily understandable by the public and provides a useful framework for teaching and research. Furthermore, the delivery of such material over the Internet turns heritage itself into a virtual commodity with all the associated economic advantages. Freed from physical and geographical constraints the material can be made available to a much wider audience at remote locations.

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