3D reconstruction of mirror-type objects using efficient ray coding

Mirror-type specular objects are difficult to reconstruct: they do not possess their own appearance and the reflections from environment are view-dependent. In this paper, we present a novel computational imaging solution for reconstructing the mirror-type specular objects. Specifically, we adopt a two-layer liquid crystal display (LCD) setup to encode the illumination directions. We devise an efficient ray coding scheme by only considering the useful rays. To recover the mirror-type surface, we derive a normal integration scheme under the perspective camera model. Since the resulting surface is determined up to a scale, we develop a single view approach to resolve the scale ambiguity. To acquire the object surface as completely as possible, we further develop a multiple-surface fusion algorithm to combine the surfaces recovered from different viewpoints. Both synthetic and real experiments demonstrate that our approach is reliable on recovering small to medium scale mirror-type objects.