CeVis
  1. Center of Complex Systems and Visualization
  2. Lehre
  3. Oberseminar

In dem regelmäßig stattfindenden Oberseminar tragen Gäste aus aller Welt über Forschungsarbeiten zu Themen vor, die mit der Arbeit von CeVis und MeVis in Verbindung stehen, und Mitarbeiter von CeVis und MeVis präsentieren ihre neusten Ergebnisse.

Program for the Summer-Semester 2006

04.05.2006, 11:00
Fully Automatic Model-Based Segmentation of the Heart
Date: 04.05.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Jürgen Weese
Philips Research Laboratories Aachen

Fully Automatic Model-Based Segmentation of the Heart

Segmentation of the heart is an essential tool that enables image inspection and the determination of important functional parameters such as the ejection fraction, wall thickening or wall motion. As manual and semi-automatic segmentation consumes a lot of time, fully automatic segmentation is highly desired and can be seen as an enabling technology for the fast and comprehensive inspection of cardiac images. Within the talk, a model-based approach for the fully automatic segmentation of the full heart is presented. The method is based on a geometrical model of the heart represented by a triangular mesh. To each triangle of the mesh further information is attached that provides anatomical information as well as information required for the adaptation of the model to images. In particular, suitable feature functions for boundary detection are learned from sample images and attached to each triangle to enable reliable adaptation of the heart model to images. For segmentation, the heart center is localized in a first step. Afterwards, the heart model is adapted to the images. During this process successively more degrees of freedom are allowed. The results for the automatic heart segmentation in MSCT images show that the approach works fully automatically in about 90% of cases tested with good to very good results according to an evalutation of clinical experts. Finally it is illustrated that the entire technology can also be used for the fully automatic segmentation of other anatomical structures and organs.

Jürgen Weese , Philips Research Laboratories Aachen
10.05.2006, 11:00
Simultaneous homogenization and registration of histological serial sections
Date: 10.05.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Stefan Wirtz
MeVis

Simultaneous homogenization and registration of histological serial sections

In registration of histological serial sections one has to deal with a huge amount of data. Beneath this, inhomogeneities from staining cause many misalignments during the registration process. State-of-the-art approaches tackle homogenization and registration separately. But there is a dependency between homogenization and registration, so both processes have to been done simultaneously. The simultaneous homogenization and registration is modelled as a minimization problem of a functional consisting of a distance measure and regularizers for the displacement field and the grayscale correction term. The new approach enables an automatic correction of gray values and improves the local contrast. The combined approach takes slightly more computing time for an optimization step as compared to the non-combined scheme and so is much faster than sequential methods.

Stefan Wirtz , MeVis
07.06.2006, 11:00
Blood Advection in RFA Simulation – Concepts, Experiments, Prototypes, and Insights
Date: 07.06.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Tim Kröger
CeVis

Blood Advection in RFA Simulation – Concepts, Experiments, Prototypes, and Insights

The cooling effect due to blood perfusion is an important aspect of numerical simulation of radio frequency ablation. The talk gives a chronologic overview of my recently developped concepts, performed experiments, implemented prototypes, and achieved insights. As a conclusion, the talk will suggest a rather simple (and well-known) model of perfusion handling, but at the same time, it will show that some amount of work will have to be spent on the simulation of the formation and the effect of thromboses.

Tim Kröger , CeVis
14.06.2006, 11:00
Dimension theory: historical overview and some important results
Date: 14.06.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Prof. Vesko Valov
Department of Computer Science and Mathematics, Nipissing University, Canada

Dimension theory: historical overview and some important results

Different types of topological dimensions (inductive, covering, cohomological and extension) will be described. Some of the most important results in dimension theory will be also presented.

Prof. Vesko Valov , Department of Computer Science and Mathematics, Nipissing University, Canada
15.06.2006, 11:00
Vision and Color: implications for effective communication
Date: 15.06.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Prof. Richard F. Voss
Florida Atlantic University, Boca Raton

Vision and Color: implications for effective communication

The optics of the eye and the neurophysiology of vision have important implications for the effective use in technology in communication.

Prof. Richard F. Voss , Florida Atlantic University, Boca Raton
28.06.2006, 11:00
Modelle zur prognostischen und prädiktiven Vorhersage des Outcomes von Patienten in der Onkologie: Der Einsatz maschineller Lernverfahren
Prof. Dr. Manfred B. Wischnewsky , ZAIT, University of Bremen
29.06.2006, 11:00
Computational Methods for Quantifying Uncertainty in Biological Modeling
Prof. Dr. R. M. Kirby , SCI, University of Utah, USA
03.07.2006, 11:00
Complex wavelets and an application to image fusion
Date: 03.07.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Prof. Dr. Brigitte Forster
Centre for Mathematical Sciences Munich University of Technology and Institite of Biomathematics and Biometry GSF National Research Centre for Environment and Health

Complex wavelets and an application to image fusion

Multiresolution analyses have proven to be an adequate tool for signal analysis. But for some applications, e.g. in speech processing and digital holography, complex-valued scaling functions and wavelets are more favourable than real ones, since they allow to deduce the crucial phase information. Our approach to complex multiresolution analyses consists in the extension of the classical resp. fractional B-splines to complex B-splines. We perform this by choosing a complex exponent, i.e., a complex order z of the B-spline, and show that this does not influence the basic properties such as smothness and decay, recurrence relations and others. Moreover, the resulting complex B-splines satisfy a two-scale relation and generate a multiresolution analysis of L^2(R). We show that the complex B-splines converge to Gabor functions as Re z increases and Im z is fixed. Thus they are approximately optimally time-frequency localized.

As an example for the application of complex wavelets we give a method for image fusion in bright field microscopy.

This is joint work with Michael Unser and the Biomedical Imaging Group, EPF Lausanne.

Keywords: Complex-valued wavelets, B-splines, multiresolution analysis, Gabor functions, image fusion

References:
  • Brigitte Forster, Thierry Blu and Michael Unser: (Complex B-Splines (Applied and Computational Harmonic Analysis, Volume 20, Issue 2, Pages 261-282, March 2006
  • Brigitte Forster, Dimitri Van De Ville, Jesse Berent, Daniel Sage, Michael Unser: Complex Wavelets for Extended Depth-of-Field: A New Method for the Fusion of Multi-Channel Microscopy Images Microscopy Research and Technique 65, p. 33-42, 2004

Prof. Dr. Brigitte Forster , Centre for Mathematical Sciences Munich University of Technology and Institite of Biomathematics and Biometry GSF National Research Centre for Environment and Health
05.07.2006, 11:00
Petri Net Models and Applications
Date: 05.07.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Lawrence Cabac
Universität Hamburg
Download talk.

Petri Net Models and Applications

In my talk I will give a short introduction to Petri nets and reference nets, which combine Petri net concepts with those of object-orientation. Reference nets can be executed efficiently in Renew (The Reference Net Workshop), an extensible editor and simulator/VM for multiple formalisms, including reference nets, p/t-nets, feature structure nets, workflow nets, etc.
The reference net-based model Mulan (Multi-Agent Nets) is a conceptual model of a FIPA-conform (Foundation for Intelligent Physical Agents) multi-agent system (MAS) implemented in reference nets and executable in Renew. It is extended by Capa (Concurrent Agent Platform Architecture) to provide FIPA-compliant communication, which enables Mulan/Capa to communicate within a heterogeneous MAS environment. To show the modeling power and the transformation from model to executable model/implementation, the conceptual architecture of a plugin management system (PMS) will be presented. This is also the conceptual basis of the plugin system implemented in Renew (since version 2.0). Furthermore, some similarities of agent systems and plugin systems will conclude the presentation.
The models will be presented and executed in Renew.

Lawrence Cabac , Universität Hamburg
11.07.2006, 11:15
On Intensity Correction Algorithms for MRI Data
Dr. Feng Huang , Research Scientist, Invivo Corp. - Diagnostic Imaging, Gainesville, FL
19.07.2006, 11:00
Multigrid Methods for the solution of Partial Differential Equations
Tobias Preusser , CeVis
26.07.2006, 14:00
Bericht: Doktorandentraining ISMRM, am MPI für neurologische Forschung Köln I) Nager, Fische und Vögel: Kleintiermodelle in der medizinischen Grundlagenforschung. II) Das Bildverarbeitungsframework im MPI für neurologische Forschung Köln
Date: 26.07.2006
Time: 14:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Hans Drexl, Markus Wenzel
MeVis

Bericht: Doktorandentraining ISMRM, am MPI für neurologische Forschung Köln I) Nager, Fische und Vögel: Kleintiermodelle in der medizinischen Grundlagenforschung. II) Das Bildverarbeitungsframework im MPI für neurologische Forschung Köln

I) Mit Kleintiermodellen lassen sich Hirnkrankheiten isoliert hervorrufen und beobachten. Das ist von Nutzen, um Bildgebungsmodalitäten und Therapieansätze unter kontrollierten Bedingungen zu erproben. Nach vorheriger Erwägung ethischer Aspekte bieten Kleintiermodelle zudem die Möglichkeit, Diagnosen und Befunde, die durch die Bildgebungsmodalitäten nichtinvasiv gestellt wurden, durch post-mortem-Untersuchungen zu verifizieren, validieren und zu erweitern. Das ist auch unter dem Gesichtspunkt des sich rapide entwickelnden Feldes "Molecular and Functional Imaging" relevant.

Wir wollen die besonderen Problematiken und die Reichweite medizinischer Grundlagenforschung an einigen Beispielen verdeutlichen.

II) Das MPI entwickelt mit einigen Programmierern ein Bildverarbeitungsframework namens VINCI. Wir wollen die Features dieser frei im Netz erhältlichen Software vorstellen. Unseren Eindruck im Vergleich zu MeVisLab schildern wir im zweiten Teil des Vortrags.

Hans Drexl, Markus Wenzel , MeVis
27.07.2006, 14:00
Classification of NMR spectra for clinical applications
Date: 27.07.2006
Time: 14:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Dr. Uwe Himmelreich
Max-Planck-Institute for Neurological Research Cologne and Centre for Infectious Disease and Microbiology, Westmead Hospital, Australia

Classification of NMR spectra for clinical applications

Current non-invasive methods in routine diagnosis of brain lesions are able to identify the mass lesions, however, they are not able to differentiate between them unequivocally (e.g. tumour, benign or infective lesion). Surgery remains necessary to provide definite diagnosis. Applications of localised in vivo NMR spectroscopy, NMR spectroscopy of biopsy samples and NMR spectroscopy of infection causing microorganisms for the diagnosis of infections and tumours will be discussed.

The main focus will be on the classification of the NMR spectra according to pathology. Supervised and unsupervised methods as well as various feature extraction and classification methods will be compared to address the various classification problems. Such problems include: low spectral resolution, low signal-to-noise ratio, data sets with low number of members per class as well as data sets with excessive number of classes.

Dr. Uwe Himmelreich , Max-Planck-Institute for Neurological Research Cologne and Centre for Infectious Disease and Microbiology, Westmead Hospital, Australia
22.08.2006, 09:30
Modulators of Aging: Genes or Fractals?
Date: 22.08.2006
Time: 09:30:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Prof. Dr. Andres Kriete
Drexel University, Philadelphia

Modulators of Aging: Genes or Fractals?

Aging is a process changing structure and function at almost any level of biological organization, being a major risk factor for diseases like cancer, diabetes, and dementias. Biological complexities, different model systems and a variety of experimental approaches have so far prevented a consistent explanation; rather different opinions or theories of aging coexist. It appears that one key to understand aging is to take a broader systems approach, which not includes the use of bioinformatics data, but also quantitative imaging. Gaining knowledge of system level properties deciphers feedback loops between processes and different levels of biological organization, the role of stochastic events, robustness and fractality. The new view offers surprising insights for interpretation of lifespan variations between individuals, differences between organisms and cause for chronic disorders.

Prof. Dr. Andres Kriete , Drexel University, Philadelphia
05.09.2006, 11:00
Biomarkers and Molecular Imaging
Prof. Dr. Andres Kriete , Drexel University, Philadelphia
12.09.2006, 10:30
Visualisierung baumartiger anatomischer Strukturen mit MPU Implicits
Prof. Dr. Bernhard Preim , Universität Magdeburg
12.09.2006, 11:00
METK - Das MedicalExplorationToolkit
Konrad Mühler , Universität Magdeburg
12.09.2006, 11:30
Der NeckSurgeryPlanner
Christian Tietjen , Universität Magdeburg
12.09.2006, 14:15
Reduktion von Artefakten in ISO-Oberflächen aus binären Volumendaten
Ragnar Bade , Universität Magdeburg
12.09.2006, 14:45
Haptische Interaktion zur Planung von Nasennebenhöhlen-Operationen
Arno Krüger , Universität Magdeburg
13.09.2006, 11:00
Wahrnehmungsbasierte medizinische Visualisierung
Prof. Dr. Bernhard Preim , Universität Magdeburg
14.09.2006, 09:45
Kardio-MRT: Aktueller Stand und zu bewältigende Aufgaben
Dr. Frank Grothues , Universität Magdeburg, Medizinische Fakultät
15.09.2006, 11:00
Neue Techniken zur Visualisierung und Exploration von Gefäßbäumen
Prof. Dr. Bernhard Preim , Universität Magdeburg
25.09.2006, 14:15
Simultaneous extraction of 12 organs from abdominal CT image
Prof. Akinobu Shimizu , Tokyo University of Agriculture and Technology
26.09.2006, 11:00
Matching von Baumstrukturen in der medizinischen Bildverarbeitung
Jan Metzen , Universität Münster
27.09.2006, 11:00
Verwendung von Textur in der Gefäßvisualisierung
Date: 27.09.2006
Time: 11:00:00
Place: CeVis/MeVis, Seminarraum Mandelbrot, UNI 29
Speaker: Christian Hansen
MeVis
Download talk.

Verwendung von Textur in der Gefäßvisualisierung

In dem Vortrag wird ein Konzept zur Visualisierung von anatomischen Gefäßbäumen unter Verwendung von Textur vorgestellt. Unter Textur (lat. textura = Gewebe) wird dabei die Oberflächenstruktur von Objekten verstanden.

Im Zentrum der Betrachtung steht der Einsatz von Textur für die Multiparameterdarstellung und die intraoperative Projektion von Gefäßbäumen. Ferner behandelt der Vortrag die Evaluierung, welche in Form einer Benutzerstudie durchgeführt wurde. Abschließend werden die entwickelten Visualisierungsszenarien in MeVisLab präsentiert und relevante Module erläutert.

Der Vortrag beruht auf den Arbeiten bei MeVis, die im Rahmen der Diplomarbeit von Christian Hansen durchgeführt wurden. Die Diplomarbeit kann unter folgender Adresse eingesehen werden: http://isgwww.cs.uni-magdeburg.de/cv/pub/files/DA_ChristianHansen.pdf

Christian Hansen , MeVis
28.09.2006, 14:15
Two talks: (1) Development of CAD of liver cancer; (2) CAD competition for liver cancer detection in Japan
Prof. Akinobu Shimizu , Tokyo University of Agriculture and Technology

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