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Colloquy Cycle WS 2005/2006
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| Current Schedule
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In the winter term of 2005/2006 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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Visual Exploration of Complex Information Spaces through Coherent Dynamic Textual Annotations
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Knut Hartmann, University of Magdeburg
Scientific and technical textbooks, documentations and visual dictionaries should convey fairly complex subject matters in an easy-to-understand way.
These types of learning materials heavily rely on illustrations to achieve various tasks in parallel:
1. Introduce a large amount of unknown terms either in a domain-specific or foreign language,
2. Explain complicated spatial configurations,
3. Provide classifications and descriptions for domain entities, and
4. Pin-point the reader's attention at important features in the illustration.
Therefore, these illustrations are carefully tuned to the above-mentioned communicative functions. Moreover, the illustrations have to be coordinated
with the associated text segments. This is mainly achieved by establishing links between visual and textual elements. In practice, human illustrators
employ a number of techniques: Labels, legends, and figure captions which provide denotations, technical terms, and descriptions for visual elements.
An interactive 3D browser is well suited to explore complex spatial configurations (Task 2) and can ease the mental integration of visual and textual
information (Task 1, 3) through a synchronized object selection and highlighting mechanism (Task 4). Moreover, the properties of the visual elements
viewing direction, graphical emphasis techniques) as well as the layout of the visual and textual element can be adjusted according to the user specific
requirements. This scenario raises a challenging dynamic layout problem which has to be solved by automated and real-time layout algorithms.
This talk presents a novel system that integrates 3D information with dynamic textual annotations. It presents real-time layout algorithms for
annotation placement. The demo compares several implemented layout styles with their hand-drawn counterparts in order to demonstrate the flexibility
of the system.
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Enforcing Regular Structures in Synthesizing Near-Regular Textures
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Jan Meseth, Universität Bonn
Rendering highly realistic images requires - besides other things - suitable materials for covering modelled objects. Despite the big advantages of
parametric material models (e.g., compact storage and efficient and/or intuitive modification by adjusting, interpolating or otherwise mixing parameters),
the best results are currently achieved employing material representations derived from sampling real materials. Due to physical limitations the spatial
extent of sampled materials is limited. This limitation can be overcome by texture synthesis methods which handle most types of materials in a satisfying
way today. In the talk a method for capturing and reproducing regular structures in materials is presented which is based on fractional Fourier analysis.
The approach is applied to texture synthesis to enable fully automatic handling of the special yet highly relevant class of near-regular textures, which
was not possible previously. Since regular structures are captured by a parametric model the approach marks a step towards automatic high-quality
modelling of real-world materials by parametric models.
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Transfer Functions Design Based on Statistical Shape Models
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Peter Kohlmann, Universität Siegen
This presentation examines statistical models for transfer functions
based on an initially generated set of manually assigned transfer
functions with respect to a very specific type of data set and a
strictly delimited type of application. The process of transfer
function design is decoupled from the specialized knowledge about the
transfer function domain (intensity, gradient magnitude etc.).Transfer
function design is difficult because of the high degrees of freedom
and the lack of a truly goal-directed process.
Existing approaches have been developed for automatic of
semi-automatic transfer function design and can be categorized in
image-driven and data-driven techniques. To concentrate on the
anatomical or functional structures which are interesting for the user
an application-driven method is needed. For a well-defined
application scenario it is possible to reduce the complexity of
transfer function generation by restricting the classification process
to structures of interest for a specific examination procedure.
At first, transfer functions are manually generated for an initial
collection of volume data sets that has been recorded for one specific
clinical purpose. A single transfer function is represented by a set
of parameters of geometric primitives (ramps or trapezoids). Each of
these individually assigned transfer functions can be regarded as a
point sample in the (high-dimensional) parameter space of the transfer
function model. From this set of point samples in parameter space a
statistical shape model is created by applying Principal Component
Analysis. A higher-level transfer function models, with only a very
limited set of parameters, based on this analysis is established to
make the process of transfer function setup very simple and intuitive.
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