A method to register multiple range images from unknown viewing directions

This paper presents a total system to register multiple range images to obtain complete object shape in the case where their relative viewing positions are unknown. To determine the relative position of. each viewpoint with respect to a common world coordinate system, the correspondences of the object's planar faces are used. For non-polyhedral objects, we produce a three dimensional convex hull of partial shape of the object observed in each range image. In the every two consecutive images, corresponding faces are found by matching adjacency graphs of their large faces. Then, the relative rotations between all viewpoints are calculated simultaneo~isly by least squares fitting with a constraint that the rotation matrix should he orthonormal with unit determinant. Relat,ive translations are obtained by simple least squares fitting.