Image Analysis and Computer Graphics > Research > Visualization


Global Illumination

This image is rendered in real-time. Various techniques have been used to create multiple reflections from planar and curved reflectors. Finally, this was combined with a radiosity solution. The richness of real world illumination is rarely captured in computer graphics. However, many inroads have been made in recent years, and it is now possible to render effects such as reflections, shadows, indirect illumination, caustics, translucent materials and participating media. Most of these effects have been made possible through the use of Photon Mapping. Photon mapping was originally invented at the department and it is still an area of research. However, many global illumination effects are still hard or impossible to achieve in real-time rendering. For instance, soft shadows in real-time systems is still a research topic. Hence, another important focus of our research is to incorporate global illumination effects in real-time rendering. Ultimately, the goal is to blur the distinction between real-time rendering and off-line rendering. Recent real-time projects include multiple specular reflections from curved and planar reflectors, accelerated form factor computation for radiosity, dynamic relighting, and soft shadows. more

Contact: Niels Jørgen Christensen, Bent Dalgaard Larsen

Point Rendering

In this image, a random selection of points have been used as an impostor for a tree model that is more costly to render. Points were first proposed as a rendering primitive in the mid-eighties but have received little interest till recently. However, points have some benefits in conjunction with very large data sets. When the average projected size of each triangle approaches a pixel it begins to make sense to render points instead of triangles. In connection with volume data, points also have the advantage that they are faster to generate than triangles, thus points are well suited for dynamic data. Finally, since points have not connectivity (as opposed to triangles) there are no cache issues. We have proposed techniques for point rendering of distance fields and medical volume data. Currently, we are experimenting with point rendering of dynamic volume data and LOD encompassing techniques for point rendering of complex objects such as trees.

Contact: Andreas Baerentzen

Visualization and Manipulation of Medical Data

The preintegrated (i.e. using slabs insted of slices) texture-based volume rendering method was used to generate an isosurface with few artefacts. Medical visualization on commodity hardware has become feasible thanks to the enormous recent advances in the field of consumer graphics cards. This project is a part of the collaborative 3D-Med project whose goal is the development of a PC-based medical workstation for viewing and measurement of volumetric, medical data such as CT or MR scans. Our goals include fast texture based visualization of large volumes, flexible and intuitive tools for adjusting transfer functions, likewise intuitive tools for measurement, and finally tools for manipulation of bone structures using shape modelling techniques.

Contact: Bjarke Jakobsen