Simultaneous reflectance estimation and surface shape recovery using polarisation

In this paper we develop a practical method for estimating shape and reflectance using only three polarised images. Using polarised light and retro-reflection settings during image acquisition, we separate the diffuse and specular reflectance components using Blind Source Separation without the accurate knowledge of the polariser angle information. Next, we compare the capacities of five chosen reflectance models, and estimate parameters of appropriate models for the two separated components together with their corresponding zenith angles. Finally, we recover surface shape by using a mixture model to match the two zenith angle estimations. We present experiments to demonstrate the validity of the proposed method for a variety of materials, and we show that the proposed method is capable of accurately estimating both shape and reflectance information.