We study the problem of recovering the structure from motion of figures which are allowed to perform a controlled non-rigid motion. We use Regge Calculus to approximate a general surface by a net of triangles. The non- rigid flexing motion we deal with corresponds to keeping the triangles rigid and allowing bending only at the joins between triangles. We show that depth information can be obtained by using a modified version of the Incremental Rigidity Scheme devised by Ullman (1984). We modify this scheme to allow for flexing motion and call our version the Incremental Semirigidity Scheme.
