Shape reconstruction from cast shadows using coplanarities and metric constraints

To date, various techniques of shape reconstruction using cast shadows have been proposed. The techniques have the advantage that they can be applied to various scenes including outdoor scenes without using special devices. Previously proposed techniques usually require calibration of camera parameters and light source positions, and such calibration processes make the application ranges limited. If a shape can be reconstructed even when these values are unknown, the technique can be used to wider range of applications. In this paper, we propose a method to realize such a technique by constructing simultaneous equations from coplanarities and metric constraints, which are observed by cast shadows of straight edges and visible planes in the scenes, and solving them. We conducted experiments using simulated and real images to verify the technique.