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 emphasises tractability and error minimisation. To this end, we discuss issues such as the acquisition and accurate simulation of material BRDFs and the light source distribution, as well as error analysis. In addition, we present a nearest neighbour resampling technique for BRDFs and a simple method for extracting the light source distribution from digitised high dynamic range images. Finally, we compare the measurements to a forward and backward raytracing solution (photon map and RADIANCE, respectively) in a set of case studies.