Realistic Materials and Illumination Environments

(2007 Alain Fournier Ph.D. Thesis Award) 

by A. Ghosh
supervised by W. Heidrich

BRDF acquisition setup

David in grace cathedral

Active lighting
Left: BRDF acquisition setup. Center: David in the Grace Cathedral environment. Right:  Active room illumination set to the Grace Cathedral environment.


Throughout its history, the field of computer graphics has been striving towards increased realism. This goal has traditionally been described by the notion of photorealism, and more recently and in many cases the more ambitious goal of perceptual realism. Photo-realistic image synthesis involves many algorithms describing the phenomena of light transport in a scene as well as its interaction with various materials. On the other hand, research in perceptual realism typically involves various tone mapping algorithms for display devices as well as algorithms that mimic the natural response of the human visual system in order to recreate the visual experience of a real scene.

An important aspect of realistic rendering is the accurate modeling of the scene elements such as light sources and material reflectance properties. This dissertation proposes a set of new techniques for efficient acquisition of material properties as well as new algorithms for high quality rendering with acquired data. Here, we are mostly concerned with the acquisition and rendering of local illumination effects. In particular, we propose a new optical setup for efficient acquisition of the bidirectional reflectance distribution function (BRDF) with basis illumination and various Monte Carlo strategies for efficient sampling of direct illumination.

The dissertation also looks into the display end of the image synthesis pipeline and proposes algorithms for displaying scenes on high dynamic range (HDR) displays for visual realism, and for tying the room illumination with the viewing environment for a sense of presence and immersion in a virtual environment. Here, we develop real-time rendering algorithms for driving the HDR displays as well as for active control of room illumination based on dynamic scene content. Thus, we propose contributions to the acquisition, rendering, and display end of the image synthesis pipeline while targeting real-time rendering applications, as well as high quality off-line rendering with realistic materials and illumination environments.