Metric depth recovery from monocular images using Shape-from-Shading and specularities

Abstract

Despite recent advances in modeling the Shape-from-Shading (SFS) problem and its numerical solution, practical applications have been limited. This is primarily due to the lack of perspective SFS models without the assumption of a light source at the camera centre and the non-metric spatial localisation of the reconstructed shape. In this work, we propose a novel formulation of the SFS problem that allows the reconstruction of surfaces lit by a near point light source away from the camera centre. We also show how knowledge of the light source position can enable the recovery of depth information in a metric space by triangulating specular highlights. Validation of the proposed technique is reported on synthetic and endoscopic images.