Ensemble Learning for Reectometry

Abstract

In “Blind Reflectometry” (Romeiro and Zickler, 2010 [3]) we describe a variational Bayesian approach to inferring material properties (BRDF) from a single image of a known shape under unknown, real-world illumination. This technical report provides additional details of that approach. First, we detail the prior probability distribution for natural lighting environments. Second, we provide a derivation of the bilinear likelihood expression that is based on discretizing the rendering equation. Third and finally, we provide the update equations for the iterative algorithm that computes an approximation to the posterior distribution of BRDFs.