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Colloquy Cycle SS 2004
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| Current Schedule
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In the summer term of 2004 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)
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| Date | Speaker | Title | Time | Location |
| 05.03.2004 |
Balazs Csebfalvi (Budapest University of Technology and Economics, Hungary)
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Monte Carlo Volume Rendering
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11.05-11.45 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 15.03.2004 |
Dieter Fellner (Universität Braunschweig, Deutschland)
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Digital Libraries: What Type Of Documents Should We Be Dealing With?
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17.00-18.00 s.t. | EI 9 Hlawka-Hörsaal, Gußhausstr. 25-29
Stiege 1/EG, 1040 Wien |
| 15.04.2004 |
Omaira Rodriguez (Universidad Central de Venezuela)
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Virtual Reality and Bioengineering Advanced technological development in Venezuela |
11.00-12.00 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 16.04.2004 |
Alan Chalmers (Universität Bristol)
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Realism in Real-Time |
11.00-12.00 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 20.04.2004 |
Karol Myszkowski (Universität Saarbrücken, Deutschland)
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Perception-motivated High Dynamic Range Video Encoding
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15.00-16.00 | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 30.04.2004 |
Ragnar Bade (Universität Magdeburg, Deutschland)
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Visualization for Medical Education and Intervention Planning
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10.00-10.45 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 30.04.2004 |
Gudrun Klinker (Technische Universität München, Deutschland)
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Confluence of Ubiquitous Computing and Augmented Reality
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11.00-12.00 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 07.05.2004 |
Wolfgang Stürzlinger (York University Toronto, Canada)
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High Dynamic Range Display Systems
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10.00-10.35 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 14.05.2004 |
Francois Faure (University Joseph Fourier, Grenoble)
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Hierarchy-accelerated collision detection
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11.00-11.30 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 18.06.2004 |
Georg Glaeser (Universität für Angewandte Kunst, Wien)
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Didaktischer Einsatz der Computergraphik am Beispiel der Simulation einer Planetenbahn
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10.00-10.40 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 25.06.2004 |
Cecilia Sikne Lanyi (University of Veszprém, Hungary)
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User interface design question in developing multimedia and virtual reality software for handicapped people
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10.00-10.45 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 15.07.2004 |
Pekka Pehkonen (University of Oulu, Finnland)
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Utilizing hypermedia for managing location-based information
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13.00 s.t. | Seminarraum 186, Favoritenstraße 9, 5. Stock |
| 22.07.2004 |
Xavier Decoret (Grenoble)
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View Independent Billboard Clouds
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15.00 s.t. | VRVis-Besprechungsraum, Donau City Straße 1, 3. Stock |
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Monte Carlo Volume Rendering
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Balazs Csebfalvi
In this paper a novel volume-rendering technique based on Monte Carlo integration is presented.
As a result of a preprocessing, a point cloud of random samples is generated using a normalized
continuous reconstruction of the volume as a probability density function. This point cloud is
projected onto the image plane, and to each pixel an intensity value is assigned which is proportional
to the number of samples projected onto the corresponding pixel area. In such a way a simulated X-ray
image of the volume can be obtained. Theoretically, for a fixed image resolution, there exists an M number
of samples such that the average standard deviation of the estimated pixel intensities is under the level of
quantization error regardless of the number of voxels. Therefore Monte Carlo Volume Rendering (MCVR) is mainly
proposed to efficiently visualize large volume data sets. Furthermore, network applications are also supported,
since the trade-off between image quality and interactivity can be adapted to the bandwidth of the client/server
connection by using progressive refinement.
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Digital Libraries: What Type Of Documents Should We Be Dealing With?
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Dieter Fellner, Germany
As if large collections of purely textual documents would not still pose
a rich set of research challenges (i.e., robust and reliable algorithms
for structuring, content extraction and information filtering) for
generations of researchers this presentation advocates a change in the
interpretation of the term ’document’: Rather than seeing a document in
a classical context of being a ’paper’ predominantly compiled of text
with a few figures interspersed we recommend to adopt a more general
view which considers a ’document’ as an entity consisting of any media
type appropriate to store or exchange information in a given context.
Only this shift in the document paradigm will open new application
fields to Digital Library (DL) technology for the mutual benefit of DL’s
and application domains: DL’s offering an unprecedented level of
functionality and (new) application domains (e.g., digital mock-up in
engineering) benefiting from a more powerful DL technology.
According to a study by Lyman et al [3] the world produces between 1 and
2 exabytes (i.e., 1018 bytes or a billion gigabytes) of unique
information per year. From that vast amount of data printed documents of
all kinds only comprise 0.003%. The major share being taken by images,
animations, sound, 3D models and other numeric data. Of course, a large
an increasing proportion of the produced material is created, stored and
exchanged in digital form - currently ranging at about 90% of the
total. Yet, little of this information is accessible through Digital
Library collections.
This presentation gives a motivation for a ’generalized view’ on the
term document and raises several issues stimulating research work in the
field of Computer Graphics to make Digital Libraries of the future more
accessible.
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Realism in Real-Time
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Alan Chalmers, Bristol
The computer graphics industry, and in particular those involved with
films, games and virtual reality, continue to demand more realistic
multi-sensory computer generated environments. In addition, there is
an ever increasing desire for multi-user networked interaction.
Despite the ready availability of modern high performance graphics
cards, the complexity of the scenes being modelled, the need for
interaction and the high fidelity required of the images and sound
means that synthesising such scenes is still simply not possible in a
reasonable, let alone real time on a single computer.
Two approaches do, however, appear to offer the possibility of
helping achieve high fidelity virtual environments in real-time: Parallel
Processing and Visual Perception. Parallel Processing has a number of
computers working together to render a single image, which appears to
provide almost unlimited performance, however, enabling many
processors to work efficiently together is a significant
challenge. Visual Perception, on the other hand, takes into account
that it is the human who will ultimately be looking at the resultant
images, and while the human eye is good, it is not that
good. Exploiting knowledge of the human visual system can save
significant rendering time by simply not computing those parts of a
scene which the human will fail to notice.
This talk will consider how parallel processing and visual perception
may be combined to achieve perceptual realism in real-time. The
application considered for this approach is the high fidelity
reconstruction of archaeological sites.
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Perception-motivated High Dynamic Range Video Encoding
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Karol Myszkowski, Germany
Due to rapid technological progress in high dynamic range (HDR)
video capture and display, the efficient storage and
transmission of such data is crucial for the completeness of any HDR
imaging pipeline. We propose a new approach for
inter-frame encoding of HDR video, which is embedded in the
well-established MPEG-4 video compression standard. The key
component of our technique is luminance quantization
that is optimized for the contrast threshold perception in the
human visual system. The quantization
scheme requires only 10--11 bits to encode 12 orders of magnitude of
visible luminance range and does not lead to perceivable contouring
artifacts. Besides video encoding, the proposed quantization
provides perceptually-optimized luminance sampling for fast
implementation of any
global tone mapping operator using a lookup table.
To improve the quality of synthetic video sequences, we introduce
a coding scheme for discrete cosine transform (DCT) blocks with
high contrast. We demonstrate the capabilities of HDR video in
a player, which enables decoding, tone mapping, and applying
post-processing effects in real-time. The tone mapping algorithm as well
as its parameters can be changed interactively while the video is playing.
We can simulate post-processing
effects such as glare, night vision, and motion blur, which appear
very realistic due to the usage of HDR data.
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Visualization for Medical Education and Intervention Planning
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Ragnar Bade, Germany
In this talk we will first discuss a case-based educational system for treatment decision-making
and intervention planning of liver tumors. We will focus on the appropriateness and development of
visualization techniques for exploring patient specific data in a problem-oriented learning environment.
In this framework, NPR-techniques such as silhouettes and hatching lines are discussed.
In the second part, we outline a method for visualization of anatomic tree structures, such as vascular and
bronchial trees by means of convolution surfaces. We will go into detail of the filter design to achieve a
correct visualization of the vessel diameter and avoid irritating bulges and unwanted blending. Afterwards
examples and validation details are presented and discussed.
Example Image 1, Example Image 2.
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Confluence of Ubiquitous Computing and Augmented Reality
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Gudrun Klinker, Germany
When people hear the term "Augmented Reality" (AR) they currently
first think of a head-mounted display and a local tracking system
which superimposes virtual information into a user's field of view.
Recently, research into AR-setups has started to move away from this
primary setup. Information is presented not only in head-mounted
displays but also on world-registered monitors that can be
attached to portable instruments or which are carefully arranged
within an ubiquitous environment. Furthermore, the increasing need
for mobile AR-applications requests tracking arrangements to be laid
out in a more global scheme integrating a number of heterogeneous
trackers. To this end, an ubquitously available tracking system needs
to be able to let mobile users establish dynamic connections to
various tracking services. This talk will present several examples
which show the confluence of concepts from ubiquitous computing and
augmented reality..
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High Dynamic Range Display Systems
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Wolfgang Stürzlinger, Canada
The dynamic range of many real-world environments exceeds the capabilities
current of display technology by several orders of magnitude. In this talk I
present the results of a collaborative research project, namely the design of
two different display systems that are capable of displaying images with a
dynamic range much more similar to that encountered in the real world. One
system can be built from off-the-shelf components and the other relies on a
custom backlighting system. Software issues as well as the advantages and the
disadvantages of the two designs are discussed together with potential
applications.
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Hierarchy-accelerated collision detection
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Fancois Faure, Grenoble
We present a new framework to efficiently trade off acuracy for speed in collision detection between deformable objects.
It combines a conventional proximity detection based on hierarchical bounding volumes with a stochastic method for collision detection. The hierarchical method selects regions of possible collisions. The stochastic method randomly selects pairs of geometric primitives in these regions and make them iteratively converge to local distance minima. By tuning the number of active pairs, a trade-off between complete detection and computation speed is obtained. Preliminary results exhibit significant speedups over previous approaches.
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Didaktischer Einsatz der Computergraphik am Beispiel der Simulation einer Planetenbahn
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Georg Glaeser, Wien
Die Keplerschen Gesetze und Begriffe wie Präzessionsbewegung oder Zeitgleichung werden didaktisch mittels Computeranimationen
aufbereitet und damit innerhalb kurzer Zeit anschaulich klar.
Wieso dauert das Winterhalbjahr fünf Tage weniger als das Sommerhalbjahr?
Wie sind Tag-Nacht-Gleichen geometrisch charakterisiert?
Warum kommen wir gerade ins Zeitalter des Wassermanns?
Zum Abschluss wird eine realistische Simulation einer minutengenauen Sonnenuhr gezeigt,
deren Funktionsweise ohne zu erwähnten Begriffe völlig unverständlich wäre.
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User interface design question in developing multimedia and virtual reality software for handicapped people
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Cecilia Sikne Lanyi
The multimedia and virtual reality projects of our Laboratory during last ten years can be summarized as follows:
Tutorial and entertainment programs for handicapped children
Rehabilitation programs for stroke patients and persons with phobias
We have developed multimedia software for handicapped children having different impairments: partial-vision, hearing difficulties, loco-motive difficulties, mental retardation, dyslexia, etc.
We show the advantages of multimedia software to develop handicapped children.
What are the advantages of multimedia software to develop handicapped children's skills?
It is an audiovisual medium
It is interactive
The treatment or situation can be reproduced, the same condition can be repeated several times.
The display presentation can be set according to the visus. The size, form, contrast, colour, size of line width, etc. of the objects and the background can be selected for best suiting the patient.
It can be adjusted to the individual needs.
Multimedia systems have an effect on more then one sense, and can be more effective.
It can help creativity, it can be varied.
It is like a game: (the child does not find the exercise as penitence, he/she likes it.
The child feels the success.
One can use motivating audio feed-back.
It can be used both in individual and small-group therapy.
Also the parent can use it with success.
Most important is that the child should get interested and his/her interest is kept for long periods of time. This is not an easy task, but multimedia presentations are very effective in this respect too.
One can include in "games" into the multimedia programs.We show the special needs of the handicapped children that have to be considered when developing multimedia software.
What are the user interface design questions in developing multimedia software for handicapped children?
To draw the picture with thick contour lines for low vision -,
Give short sentences for mentally handicapped -,
Design the navigation tools for children with loco-motive difficulties.
The hearing impaired children want the sounds too.
Rehabilitation programs for stroke patients and persons with phobias.
We developed a computer controlled method which enables - as a difference to methods used internationally - not only the establishment of the diagnosis, but permits measurement of the effectiveness of the therapy. It allows
To produce a database of the patients that contains not only their personal data but also the results of the tests, their drawings and audio recordings.
It is an intensive therapeutic test and contains tutorial programs.
Now we are collecting the test results in this project.
We developed some virtual worlds for treating phobias: virtual balcony, a ten-storied building with an external glass elevator and an internal glass elevator in the virtual Attrium Hyatt hotel. We developed virtual environment for claustrophobia too: a closed lift and a room, where the wall can be moved. For specific phobias (fear of travelling) we modelled the underground travelling in Budapest. For the education we developed virtual shopping software for autistic children too.
I show the advantages of Virtual Reality in the investigation, evaluation and therapy of perception, behaviour and neuropsychological studies.
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Utilizing hypermedia for managing location-based information
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Pekka Pehkonen
Hypermedia enables the use of associative modeling and management of
information. One of the topics studied in the ATELIER -project was
hypermedia's utilization possibilities with location-based data. Special
tool called E-Diary was developed for collecting multimedia data and
location information during remote visits and for storing them in a
hypermedia database. Hypermedia combined with physical input devices
provided interesting new ways to browse through the collected data,
including gesture based navigation. This presentation illustrates the
framework and tools used to study the use of hypermedia with
location-based data.
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View Independent Billboard Clouds
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Xavier Decoret, Grenoble
Over the past years, impostors and image based simplification have been
proposed to replace complex geometry with simpler meshes and appropriate
replacement textures. Along this path, the Billboard Clouds approach
approximates the global shape of an objects with a small set of planes
and uses semi-transparent textures to capture finer details such as
silouhettes for example. The problem is cast as a geometric cover,
where a minimal set of planes is searched to intersect "regions of
validity" of the model's faces. In view-independent billboard clouds
(where the BC simplification must be usable for any viewpoint), those
regions are defined by spheres around the vertices indicating the
maximum displacement allowed during simplification. In view-independent
cases (where the BC simplification is to be used for a given viewcell),
the definition of the validity region involves an accurate computation
of the reprojection error. In this talk, we will briefly present the
view-independent billboard clouds and will then introduce our recent
results on their extension to the view-dependent case.
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