Curve-based stereo: figural continuity and curvature

An edge-based trinocular stereovision algorithm is presented. The primitives it works on are cubic B-spline approximations of the 2-D edges. This allows one to deal conveniently with curvature and to extend to some nonpolyhedral scenes to previous stereo algorithms. To build a matching primitive, the principle of the algorithm is, first, to find a triplet of corresponding points on three splines. This is provided by the bootstrapping part. Second, the algorithm propagates along the three supporting splines to find other matching points. This provides a set of ordered point triplets along these three splines, for which all the matching constraints are verified. This primitive constitutes a trinocular hypothesis. The set of all hypotheses is obtained by propagating from all the point triplets provided by the bootstrapping process. A criterion based on the size of the hypotheses is then used to choose among them a compatible set with respect to the uniqueness constraint. Results of several 3-D reconstructed scenes are shown