To derive accurate three-dimensional (3-D) information of a scene is an important pur-pose in computer vision. Two-viempoints stereo vision (we will call it stereo vision in thefollowing) is a technique for reconstructing the 3--D description of a scene from the imagesobserved from two viewpoints. The main procedure in stereo vision is: (i) define and ex-tract the primitives in images; (ii) find the correspondence of these primitives between two To derive accurate three-dimensional (3-D) information of a scene is an important pur-pose in computer vision. Two-viempoints stereo vision (we will call it stereo vision in the following) is a technique for reconstructing the 3 - D description of a scene from the imagesobserved from two viewpoints. The main procedure in stereo vision is: (i) define and ex-tract the primitives in images; (ii) find the correspondence of these primitives between two