A method for estimating light direction, shape, and reflection parameters from a single image

This paper presents a novel approach for estimating light direction, shape, and reflectance parameters from a single image based on iterative optimisation. We depart from a generalist view of the reflection process based upon a physical interpretation and cast the recovery of the reflection parameters in an optimisation setting. With the estimated specular reflectance parameters, we recover the light source direction from specular highlights while applying two novel constraints, coplanarity and Kullback-Leibler divergence. Then, by integrating the knowledge of light source direction and diffuse reflectance parameters, we recover shape of the scene from diffuse component. Our approach is quite general in nature and can be applied to a family of reflectance models that are based on the Fresnel reflection theory. We demonstrate the utility of our method on synthetic and real world imagery.