PhD defenses at the Faculty of Informatics

You are cordially invited to attend the PhD Dissertation Defense of Randolf SCHÄRFIG on Tuesday, December 6th 2016 at 14h30 in room SI-008 (Informatics building)

Abstract:
Computer graphics can nowadays produce images in realtime that are hard to distinguish from photos of a real scene. One of the most important aspects to achieve this is the interaction of light with materials in the virtual scene. The lighting computation can be separated in two different parts. The first part is concerned with the direct illumination that is applied to all surfaces lit by a light source; algorithms related to this have been greatly improved over the last decades and together with the improvements of the graphics hardware can now produce realistic effects. The second aspect is about the indirect illumination which describes the multiple reflections of light from each surface. In reality, light that hits a surface is never fully absorbed, but instead reflected back into the scene. And even this reflected light is then reflected again and again until its energy is depleted. These multiple reflections make indirect illumination very computationally expensive. The first problem regarding indirect illumination is therefore, how it can be simplified to compute it faster.
Another question concerning indirect illumination is, where to compute it. It can either be computed in the fixed image that is created when rendering the scene or it can be stored in a light map. The drawback of the first approach is, that the results need to be recomputed for every frame in which the camera changed. The second approach, on the other hand, is already used for a long time. Once a static scene has been set up, the lighting situation is computed regardless of the time it takes and the result is then stored into a light map. This is a texture atlas for the scene in which each surface point in the virtual scene has exactly one surface point in the 2{D} texture atlas. When displaying the scene with this approach, the indirect illumination does not need to be recomputed, but is simply sampled from the light map.

Dissertation Committee:

  • Prof. Kai Hormann, Università della Svizzera italiana, Switzerland (Research Advisor)
  • Prof. Marc Stamminger, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany (Research co-Advisor)
  • Prof. Marc Langheinrich, Università della Svizzera italiana, Switzerland (Internal Member)
  • Prof. Evanthia Papadopoulou, Università della Svizzera italiana, Switzerland (Internal Member)
  • Prof. Marco Tarini, Università degli Studi dell'Insubria, Italy (External Member)
  • Prof. Matthias Zwicker, University of Bern, Switzerland (External Member)