Acquisition and Visualization of Optical Material Properties

The optical reflectance behavior of materials and surfaces is of great importance for the perception of a scene. For example, the specific gloss and the texture of a surface give important hints about properties of the material it is made of. Parametric modeling of this behavior is often difficult or even practically impossible. This is especcially true for spatially varying materials. Therefore, in our group we research techniques for the effective data-driven representation of material appearance based on measurements.

In this context we focused on the acquisition, compression, editing and rendering of Bidirectional Texture Functions (BTF). BTFs are six-dimensional functions dependent on surface location as well as incoming and outgoing light directions. It is able to capture the appearance of very complex materials with strong interreflections and shadowing effects. Currently, we are investigating the extension of our RGB BTF techniques to fully spectral BTFs for correct color reproduction under arbitrary illumination.

Several devices for the acquisition of BTF have been built by our group, an overview of these and of our most important publications in this context can be found on this project page.