Begriffe, Krankheiten, Einrichtungen u.v.m., verknüpft mit dem zuständigen Bereich.
Im Menüpunkt "Übersicht" sind Einrichtungen unter verschiedenen Gesichtspunkten gruppiert: Kliniken, Abteilungen, Institute, Zentrale Einrichtungen und ähnliches.
Geometric Morphometrics and Shape analysis
The methods of modern morphometrics open a vast field of oportunities for physical anthropologists, as they allow to grasp the shape of a complex configuration of points (representing a biological feature) mathematically. Thus makes it possible to extract statistical information not only adressing a set of points but a shape as a whole. At the moment, we do research in hindsight to medical applications, anthropological questions such as sexual dimorphism, changes of osseous structures due to aging and forensic purposes like reconstructing the shape of soft tissue from information obtained by the underlying bone configuration. To achieve this, I am working with dense sets of coordinates representing surface structures by using sliding semi-landmarks.
Software development
Most of my current work involves implementing and developing various algorithms into usable software. The platform of my choice hereby is R (http://cran.r-project.org/) as it provides flexibility and the integration of C++ and Fortran routines. So far, two packages have been released on my sourceforge page (http://sourceforge.net/projects/morpho-rpackage): Morpho and Rvcg. While Morpho mainly targets landmark based shape analysis, Rvcg implements meshing routines from vcglib (Meshlab) into the R environment, thus allowing sophisticated operations from within R. These packages contain the following features:
Morpho
- Processing landmarks (Im- and Export, Procrustes registration)
- Various tools, such as detection and removal of outliers based on sample distribution
- Statistical shape analysis
- sliding of 3D Semilandmarks on triangular meshes
- Mesh import
- Mesh warping
Rvcg
- Mesh smoothing
- Mesh simplification (Quadric edge collapse decimation)
- Fast PLY import
- Closest point matching
- Very fast - based on the C++ code from vcglib
Trimesh-tools (additional command line tools)
- also based on vcglib
- available from (http://sourceforge.net/projects/morpho-rpackage/files/Auxiliaries/Binaries/)
All software is available for Linux (recommended), Mac OSX and Windows.
Contact: Stefan Schlager
Examples of our current research
Soft tissue estimation of the human nose
My current dissertation thesis tries to extrapolate shape variability of both, soft- and hard-tissue, of the human nose. It is based on surfaces generated from CT-Scans from ~500 Indivuals from Shanghai and Freiburg. The goal is to attribute the shape shifts associated with population membership, gender and age and to incorporate this knowledge into statistical models to estimate the nasal soft-tissue shape from the underlying bone tissue.
Below are some visualisations of results:
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| Ageing of the soft-tissue nose (green=old; red=young). | Population specific asymmetry (exaggerated by factor 10: Green=Chinese; red=European). | Skin patch estimated from database (visualised on original skull mesh) |
Medical Purposes
Construction of titanium mandible plates for reconstruction of the bone structure after tumor section.
Deformation based on statistical modelling
Extreme pronlongation of a nose based on information from a shape database generated by 250 European noses.The deformation tries to make the prolongation as probable as possible (with probability measured by the distribution of the database’s entries).
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Surface registration
Two facial surfaces registered by elastic surface matching.
