Current Schedule

In the winter term of 2002/2003 the following talks will be organized by our Institute. The talks are partially financed by the "Arbeitskreis Graphische Datenverarbeitung" of the OCG (Austrian Computer Society)

Date SpeakerTitleTimeLocation
12.9.2002 Soeren Grimm (Germany) What is the best way to do volume rendering in a real-world medical visualization system? 15.00-16.00 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
23.9.2002 MARCO ANTONIO GÓMEZ-MARTÍN, PEDRO PABLO GÓMEZ-MARTÍN (Universidad Complutense de Madrid, Spain) Virtual Visits and Archaeology 14.00-14.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
11.10.2002 Michael Haller (FHS Hagenberg, Austria) Virtual Reality Research at FHS Hagenberg 10.00-10.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
18.10.2002 J. Andreas Baerentzen (Danmark) Volume Sculpting using the Level-Set Method 10.00-10.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
8.11.2002 Ronan Boulic (EPFL, Switzerland) Hierarchy of Kinematic Constraints for Postural Control and Motion Editing 10.00-10.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
8.11.2002 Raphael Grasset (iMAGIS/GRAVIR, Grenoble, France) MARE : Multiuse Augmented Reality Environment for Real Table Setup 11.00-11.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
22.11.2002 Klaus Dorfmueller-Ulhaas (Germany) Optical Tracking: From User Motion To 3D Interaction 10.00-10.45 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
22.11.2002 Martin Martinov, ("St. Kliment Ohridski" University, Sofia, Bulgaria) Image Processing in Java 10.45-11.15 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
6.12.2002 Jiri Bittner (Prague, Czech Republic) Hierarchical Techniques for Visibility Computations 11.00-11.30 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
13.12.2002 Anna Vilanova Bartroli (TU Eindhoven, Holland) Biomedical Image Analysis 10.00-10.30 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
13.12.2002 Martin Wagner (Lehrstuhl für angewandte Softwaretechnik, Institut für Informatik, TU München, Germany) The SHEEP Game: Multi-Modal Collaborative Interaction Using the DWARF Architecture 10.30-11.00 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock
20.12.2002 Oliver Bimber (Bauhaus University Weimar, Germany) The Virtual Showcase: An AR Digital-Storytelling Platform? 11.00-12.00 s.t.Seminarraum 186, Favoritenstraße 9, 5. Stock

Previous Schedules


What is the best way to do volume rendering in a real-world medical visualization system?

Soeren Grimm, Germany

Today's real-world medical visualization systems for medical data are much more than just the visualization. Such systems have a back-end that stores the medical data and reports, and a front-end that assists the user in analyze and exam the data. The front-end has means to manual-segment, auto-segment, carve, measure, annotate, etc, and to view the data in 2D or 3D. The visualization is a small, but a very crucial, part of such a system. Since it is the visual feedback the user gets after he performed any operation and therefore it has to be interactive and in high quality. The 3D view is basically volume rendering and needs enormous computational power and memory bandwidth to get high quality and interactivity. There are several ways to do volume rendering, however it is still not clear what is the best way to do it in a real-world visualization system. This talk presents four different ways of volume rendering - based on SIMD, VolumePro, Texture mapping, and finally pure CPU -, their underlying volume memory layouts, and their usability in real-world visualization systems.

Keywords: Volume rendering, Ray casting, Texture Mapping, Multithreading, Hyperthreading, OpenGL, VolumePro, Parallel processing.

Virtual Visits and Archaeology

MARCO ANTONIO GÓMEZ-MARTÍN, PEDRO PABLO GÓMEZ-MARTÍN; Universidad Complutense de Madrid, Spain

The increase in the number of tourists who visit fragile monuments endangers their preservation. In other cases, an interested person can't afford the long trip required to get to the place that she wants to see. Virtual archeology seems to be the solution to both problems, because the user can see the monument in the computer and walk in it without any kind of contact. Additionally, these virtual reconstructions allow the user to ask for information about the different elements she finds there. We will show three examples of this kind of applications, like the virtual visit to the Nefertari's tomb, which we rebuilt using plans and pictures. We will describe some of the computer graphics techniques we have used to develop them. Finally, we will talk about our current research area: the addition of avatars or agents to these environments to guide the visitor.

Virtual Reality Research at FHS Hagenberg

Michael Haller; FHS Hagenberg, Austria

Media Technology and Design (MTD) is a 4-year engineering program focused on technical and creative aspects of digital media. MTD is one of several IT-related programs offered by the College of Engineering at Hagenberg as part of the Upper Austrian University of Applied Sciences (Europe).

The engineering part of the MTD curriculum includes audio/video technology, computing, networking and multi-media programming as core subjects, with a careful balance of basic and selected in-depth material.

The design part of the program starts out with elementary drafting techniques, study of shape and color, art and media history, typography, sound, and music; this is followed by advanced subjects such as multi-media design, audio and video design, 3D modeling and animation, media production and experimental media.

The Media Technology and Design (MTD) curriculum focuses on three broad areas:

  • Multimedia
  • 3D computer graphics and animation
  • Internet/WWW

The talk describes activities of MTD concerning computer graphics, Virtual Reality, and Augmented Reality. We will give a short overview of the courses and show some student projects. Finally, we will describe the European founded project AMIRE (Authoring Mixed Reality).

Related links:

Hierarchy of Kinematic Constraints for Postural Control and Motion Editing

Ronan Boulic ; (EPFL, Switzerland)

In this talk, I will present an IK architecture allowing the enforcement of multiple constraints distributed on an arbitrary number of priority levels. The cost of the IK algorithm building the projection operators is linear with the number of priority levels thus allowing interactive postural control of human characters. The talk will end on presenting our on-going work that evaluate how to apply this technique to motion editing.

Optical Tracking: From User Motion To 3D Interaction

Klaus Dorfmueller-Ulhaas; (Germany)

Tracking user movements is one of the major low-level tasks which every Virtual Re-ality (VR) system needs to fulfill. There are different methods how this tracking may be performed. Common tracking systems use magnetic or ultrasonic trackers in dif-ferent variations as well as mechanical devices. All of these systems have drawbacks which are caused by their principles of work. Typically, the user has to be linked to a measurement instrument, either by cable or, even more restraining for the user, by a mechanical linkage. Furthermore, while mechanical tracking systems are extremely precise, magnetic and acoustic tracking systems suffer from different sources of distor-tions. For this reason, an optical tracking system has been developed which overcomes many of the drawbacks of conventional tracking systems. This work is focused on stereoscopic tracking that provides an effective way to enhance the accuracy of optical based trackers. Vision based trackers in general fa-cilitate wireless interaction with 3D worlds for the users of a virtual reality system. Additionally, the proposed tracker is very economic through the use of standard sensor technology that will furthermore reduce cost. The proposed tracker provides an ac-curacy in the range of sub-millimeters, thus it meets the requirements of most virtual reality applications. The presented optical tracker works with low frequency light and is based on retro-reflective sphere shaped markers illuminated with infrared light to not interfere with the user's perception of a virtual scene on projection based display technology systems in environments with dim light. In contrast to commercial optical tracking systems, the outcome of this work is operating in real-time. Furthermore, the presented sytem can make use of very small cameras to be applicable for inside-out tracking. This work presents novel approaches to calibrate a stereoscopic camera setup. It utilizes the standard equipment used for commercial optical trackers in computer ani-mation, but contrarily to calibration methods available today, it calibrates internal and external camera parameters simultaneously, including lens distortion parameters. The calibration is very easy to use, fast and precise. To provide the robustness required by most virtual reality applications, human mo-tion needs to be tracked over time. This has been often done with a Kalman filter facilitating a prediction of motion which may not only enhance the frequency of the tracking system, but may also cope with display lags of complex virtual scenes or with acquisition or communication delays. A new filter formulation is presented that may also be used with non-optical based trackers providing the pose of an object with six degrees of freedom. Finally, some extensions to natural landmark tracking are presented using a contour tracking approach. First experimental results of an early implementation are shown, detecting a human pointing gesture in environments with different lighting conditions and backgrounds. Perspectives are given how this method could be extended to 3D model based hand tracking using stereoscopic vision.

Image Processing in Java

Martin Martinov ; ("St. Kliment Ohridski" University, Sofia, Bulgaria)

The possibilities of Java 2D, Java 3D, Java Swing and Advanced Java Imaging for doing Computer Graphics are going to be presented demonstrating them in an custom-developed program implementing the following algorithms:

  • Line-drawing: Simple method, Bresenham method, Portion method
  • Line-smoothing: area based, distance-based
  • Circle-drawing: Simple method, Bresenham method, by second-order differnces
  • Ellipse-drawing: Bresenham method
  • Line-clipping: Cohen-Sutherland method, Liang-Barsky method

Biomedical Image Analysis

Anna Vilanova Bartroli ; (TU Eindhoven, Holland)

The group Biomedical Image Analysis (BMIA) is part of the Master program Biomedical Imaging and Informatics (BMI2), one of the four Master programs in the Department of Biomedical Engineering at Eindhoven University of Technology. In this talk I will present the structure and the ongoing research projects of BMIA.

The Virtual Showcase: An AR Digital-Storytelling Platform?

Oliver Bimber ; (Bauhaus University, Weimar)

The Virtual Showcase is a new projection-based Augmented Reality display that offers an imaginative and innovative way of accessing, presenting, and interacting with scientific and cultural content. Almost three years after the development of the first proof-of-concept prototype, the Virtual Showcase is turning into an efficient multi-user display that effectively addresses several shortcomings of today's Augmented Reality displays. I will give an overview of the different Virtual Showcase prototypes built so far, their technical components, and their recent application to the field of digital story-telling for education and scientific visualization.

References
http://www.nsf.gov/od/lpa/news/02/tip021022.htm http://www.wissenschaft-online.de/artikel/605814&template=d_bnt_n_inhalt&_stempel_datum_bis=1034719199 http://cgw.pennnet.com/Articles/Article_Display.cfm?Section=Articles&Subsection=Display&ARTICLE_ID=125448 http://www.vrnews.com/invited/fa20011207.html

Curriculum Vitae
Oliver Bimber is currently a scientist at the Bauhaus University Weimar, Germany. He received a Ph.D. in Engineering at the Technical University of Darmstadt, Germany under supervision of Prof. Dr. Encarnação (TU Darmstadt) and Prof. Dr. Fuchs (UNC at Chapel Hill). From 2001 to 2002 Bimber worked as a senior researcher at the Fraunhofer Center for Research in Computer Graphics in Providence, RI/USA, and from 1998 to 2001 he was a scientist at the Fraunhofer Institute for Computer Graphics in Rostock, Germany. He initiated the Virtual Showcase project in Europe and the Augmented Paleontology project in the U.S.A. He received the degree of Dipl. Inform. (FH) in Scientific Computing from the University of Applied Science Giessen and a B.Sc. degree in Commercial Computing from the Dundalk Institute of Technology. In his career, Bimber received several scientific achievement awards and is author of more than thirty technical papers and journal articles. He was guest editor of the Computer & Graphics special issue on "Mixed Realities - Beyond Conventions", and has served as session chair and review committee member for several international conferences. Bimber also gave a number of guest lectures at recognized institutions. Among them were Brown University, Princeton University, the IBM T.J. Watson Research Center, the DaimlerChrysler Virtual Reality Competence Center, and the Mitsubishi Electronic Research Lab (MERL). His research interests include display technologies, rendering and human-computer interaction for Mixed Realities. Bimber is member of IEEE, ACM and ACM Siggraph.