About the SemSeg Project




What is the SemSeg project about?

The thorough analysis of flows plays an important role in many different processes, such as airplane and car design, environmental research, and medicine.  Scientific Visualization and its subfield flow visualization have provided a variety of techniques for the domain experts to visually analyze large and complex flow data sets.  Among them, so-called topology-based methods play an important role.  Vector field topology (VFT) is a mathematically rigorous theory that reveals the essential structure of a static vector field.  However, this approach is only fully valid for static vector fields. 

Recent developments in the target domains of this project show a clear transition from steady to unsteady flow scenarios.  Accordingly, we have to see that the traditionally proven approaches do not apply any more and that a conceptual change in the methodology of visual analysis is necessary.  Topology-based methods which account for the complete dynamic behaviour of flow fields are strongly needed but do not exist.  Steps toward this goal have been done from several sides, delivering promising but yet only partial results. 

It is the objective of this project to research a new segmentation method for unsteady flows that has the elegance and specificity of (steady) VFT, but which provides correct results for unsteady flows as well.  This project aims at the formulation of a sound theoretical mechanism to describe structural features in time-dependent flow.  Similar to the case of steady flow, were topology has proven its usefulness in many years, it is straight-forward to expect that the new approach will also establish its important role in the analysis and discussion of time-dependent flow scenarios.  As part of a successful project, concrete algorithms to extract and visualize the topological structures are derived from the new mechanism.  Implementations of them will allow studying the usefulness on a number of real-life flow data from different areas of application. 

Who is in need of SemSeg research?

In the following, we sketch a limited subset of the selected potential application areas wrt. the solutions that we expect to result from the SemSeg project. 

Automotive industry


Simulated flow within a car (left), around a car (middle), and in a cylinder of a Diesel engine (right):  three application examples of complex time-dependent flows in the automotive industry where a thorough understanding is important (all images courtesy of AVL.com).

Hydrodynamics, aerodynamics


Simulated unsteady flow in draft tube of a Francis turbine (left, visualization of data from VATECH), flow around an airplane wing (middle, work by Sahner et al.), complex 3D flow (right, visualization and data by FFI.no).

Safety, medicine


Simulation of smoke due to a fire in the ventilation of a cinema (left, data from AFC.com), blood flow near the vessel wall of an aneurysm (middle, visualization of data by AVL.com), 3D blood flow within an aneurysm in the brain (right, visualization by partner UMAG).

Meteorology, climate research


Air movements which lead an extreme weather condition over Germany in 2002 (left, work by James et al.), simulation of a ''Medicane'' (a hurricane in the Mediterranean) as maybe possible due to climate change (middle, visualization by M. Böttinger from DKRZ), simulation of ocean currents off the south-west coast of Norway (right, visualization by N. Winther from NERSC).

A brochure about the SemSeg project

We have consolidated our six-sided brochure about the SemSeg project, which can be downloaded from this web page.