Improving Bivariate BRDF Measurement by Optimizing Light Directions

Abstract

We propose a method for measuring reflectance with a simple setup based on bivariate BRDF, a simplified version of BRDF. Most measurement methods require large systems for illuminating target objects from various lighting directions. Our method reduces the number of lights by finding light directions suited for a target shape via combinatorial optimization. We also reduce artifacts occurring when recording reflectance, which stem from the narrow representation domain of bivariate BRDF. We further reduce the impact of clustering errors in case of objects containing multiple materials. In summary, we demonstrate our method can capture reflectance more accurately with less lights.