Virtual Reality

Since November 2004, we possess an immersive projection system, a device that makes three dimensional computer generated worlds "walkable". What this means, immediately becomes obvious when one uses such a system. But let's try to explain: we dispose of a back projection screen, which is 2.5 metres wide and has a height of 2 metres. Two projectors illuminate the screen from behind, one projects the image for the left eye, the other for the right one. Polarising filters in front of the projector lenses and corresponding ones within the glasses users are obliged to wear ensure that every eye only sees the corresponding image.

A wireless tracking system measures the head position of the beholder and enables the image generating computers to render specially adapted views of the scene several times per second - one for the left and another for the right eye respectivly. In this way the human ability of stereoscopic viewing can be exploited in order to give an impression as realistic as possible. This makes the user feel more present in the virtual environment and raises her attention for it. But above all, the abilities for spatial perception, which are very well trained from everyday life, can be used to gain insight into structures that are only present within the computer. As the rendered image is adapted to the viewer's position, the user can move in front of the projection screen and has the impression to move around the virtual model. By means of this natural way of interaction with the scene, comprehension is additonally augmented.

When is it especially advantageous to use these technologies? Three dimensional representation is immediately useful when the data to be explored has a canonical 3D structure. For instance, computational fluid dynamics as used in meteorology or in the automotive industry yield such data. Simulations from astronomy and chemical sciences also produce three dimensional output. But visualisation is not limited to synthetic data: medical volume data such as from computed tomography or magnetic resonance imagery possess natural placement in space. Geological layer models are also a possible source of data. Architects and archeologists profit from making buildings and other structures walkable that are not yet built or do not exist any longer. If there isn't a canonical embedding in 3D space, then there is the possibility to use the additional degree of freedom to untangle otherwise unmanageable information clutter - the areas of use are manifold.

For driving the projection screen, the software COVISE is used. Under the direction of Prof. Ulrich Lang it was developed at the supercomputing centre at the University of Stuttgart (HLRS). Since Prof. Lang is head of the computing centre here (RRZK) development continues jointly with HLRS and the software is available for free to all academic users here at the University of Cologne. But also the immersive projection screen is accessible to all members of the University. As COVISE does not only support the visualisation in a virtual environment but also on the desktop, it is possible to preprocess your data at your workstation before analysing it more thoroughly with the immersive projection system or before presenting it to a larger audience.

Are you interested in using COVISE or the immersive projection screen? Then we encourage you to participate in the COVISE course. There you will gain profound insight into the possibilities of COVISE and of virtual reality. But you can also talk directly to us, please address Prof. Lang.