 |
Colloquy Cycle WS 2006/2007
|
| Current Schedule
| |
In the winter term of 2006/2007 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 | Speaker | Title | Time | Location |
| 20.10.2006 |
Torsten Möller
(Simon Fraser University, Canada) |
A Spectral Analysis of Function Composition and Its Implications
for Sampling in Direct Volume Visualization
|
10:00 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
| 20.10.2006 |
Klaus Müller
(State University of New York at Stony Brook) |
Volumetric Datasets: Conception and An Enriched Life
|
11:00 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
| 10.11.2006 |
Jean Pierre Charalambos
(Universitat Politècnica de Catalunya) |
Coherent Hierarchical Level of detail (HLOD)
Refinement Through Hardware Occlusion Queries
|
10:30 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
| 24.11.2006 |
Philip Willis
(University of Bath) |
Projective Alpha Colour and its Application
|
10:30 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
| 12.1.2007 |
Sergi Grau
(University of Barcelona) |
Temporal coherence in rendering time-varying volume data
|
10:30 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
| 2.2.2007 |
Dr. Renate Sitte
(Griffith University) |
Challenges in Mems Virtual Prototyping
|
10:30 | Seminarroom 186/2, Favoritenstraße 9,
5. Stock |
|
A Spectral Analysis of Function Composition and Its Implications
for Sampling in Direct Volume Visualization
|
|
Torsten Möller, Simon Fraser University
In this talk we investigate the effects of function composition in the
form g(f(x)) = h(x) by means of a spectral analysis of h. We decompose the
spectral description of h(x) into a scalar product of the spectral
description of g(x) and a term that solely depends on f(x) and that is
independent of g(x). We then use the method of stationary phase to derive
the essential maximum frequency of g(f(x)) bounding the main portion of
the energy of its spectrum. This limit is the product of the maximum
frequency of g(x) and the maximum derivative of f(x). This leads to a
proper sampling of the composition h of the two functions g and f. We
apply our theoretical results to a fundamental open problem in volume
rendering -- the proper sampling of the rendering integral after the
application of a transfer function.
|
|
Volumetric Datasets: Conception and An Enriched Life
|
|
Klaus Müller, State University of New York at Stony Brook
Fully 3D datasets have become ubiquitous in a wide range of disciplines, such as science, engineering, medicine,
and even entertainment. There is a vast demand to efficiently create these data, as well as fuse, relate, and visualize them.
In this talk I will report on our efforts in all of these domains. First I will discuss techniques that utilize GPUs for
rapid tomographic volume reconstruction and even direct volume visualization from X-ray projection data. Then I will describe
our Magic Volume Lens framework which fuses and augments different types of volumetric data at different scales into one
composite representation, providing a variety of zoom lenses for focus+context GPU-accelerated viewing with semantic context.
|
Coherent Hierarchical Level of detail (HLOD)
Refinement Through Hardware Occlusion Queries
|
|
Jean Pierre Charalambos, Universitat Politècnica de Catalunya
We present a coherent hierarchical level of detail (HLOD)
culling algorithm that employs a novel metric to perform the refinement of
a HLOD-based system that takes into account visibility information. The
information is gathered from the result of a hardware occlusion query
(HOQ) performed on the bounding volume of a given node in the hierarchy.
Although the advantages of doing this are clear, previous approaches treat
refinement criteria and HOQ as independent subjects. For this reason, HOQs
have been used restrictively as if their result were boolean. In contrast
to that, we fully exploit the results of the queries to be able to take
into account visibility information within refinement conditions. We do
this by interpreting the result of a given HOQ as the virtual resolution
of a screen space where the refinement decision takes place. In order to
be able to use our proposed metric to perform the refinement of the HLOD
hierarchy as well as to schedule HOQs, we exploit the spatial and temporal
coherence inherent to hierarchical representations. Despite the simplicity
of our approach, in our experiments we obtained a substantial performance
boost (compared to previous approaches) in the frame-rate with minimal
loss in image quality.
|
|
Projective Alpha Colour and its Application
|
|
Philip Willis, University of Bath
Image compositing is combining two or more images by overlaying them. For
this to be meaningful, some of the image areas need to be less than
perfectly opaque, so the rearmost images can be seen. When Porter and Duff
wrote their 1984 paper on Image Compositing, they used a four channel colour
model (r,g,b,a). The extra channel, called alpha, represented the opacity of
the colour (r,g,b). We have recently shown that this is mathematically a
projective space, which extends the range of use of the alpha colour model,
including to applications beyond compositing. This published work will be
described. We also have some very recent unpublished results and these too
will be presented.
|
|
Temporal coherence in rendering time-varying volume data
|
|
Sergi Grau, University of Barcelona
This presentation introduces myself and explains briefly which are my research activities
|
|
Challenges in Mems Virtual Prototyping
|
|
Dr. Renate Sitte, Griffith University
|
|
