3-D recognition and shape estimation from image contours using invariant 3-D object curve models

The problem of recognizing and estimating the shape of objects with special markings (text, symbols, drawings, etc.) on their surfaces using B-spline curve modeling and a pair of binocular images is considered. As a direct consequence of the invariance of the B-splines to affine transformations the computation of the 3-D coordinates of the object curve points from a pair of stereo images becomes a straightforward task, and is obtained using minimum-mean-square-error estimation. The 3-D curve is recovered from the estimated object curve control points, and is subsequently used for the object shape estimation and classification