Physical validation of global illumination methods: Measurement and error analysis

In this paper, we present a physical validation of global illumination algorithms based on measurements from a simple experimental setup. The validation methodology emphasizes tractability and error minimization. To this end, we discuss issues such as the acquisition and accurate simulation of material bidirectional reflection distribution functions (BRDFs) and the light source distribution, as well as error analysis. In addition, we present a nearest-neighbor resampling technique for BRDFs and a simple method for extracting the light source distribution from digitized high dynamic range (HDR) images. Finally, we compare the measurements to a forward and backward raytracing solution (photon map and RADIANCE, respectively) in a set of case studies.