Hierarchical Reconstruction of BRDFs using Locally Supported Functions

BRDFs are the backbone of realistic rendering algorithms. Analytical models are sometimes ineffective since they frequently cannot represent very particular material characteristics (retro-reflection, anisotropy, off-specularity, …). Consequently one might want to use measured BRDF data directly; this leads to solving the problem of BRDF reconstruction. In this paper, we propose a new solution which uses locally supported functions that lead to a hierarchical approach able to take irregular distributions of sampled data into account. This method is not computationally expensive and guarantees a physically valid reconstruction. We also discuss the quality of the reconstruction, introducing some new error parameters.