<title>Application of Fourier transform profilometry to the recognition of 3-D objects</title>

Abstract

Fourier transform profilometry, a well-known technique to obtain images of three-dimensional (3-D) objects, is used to achieve a real-time optical recognition of 3-D objects. A distorted grating pattern, that carries all the 3-D information of the object, is obtained from the projection of a regular fringe pattern onto the 3-D object surface. The analysis of such patterns is the basis of the optical method for recognizing 3-D objects in real time. The performance of the technique is demonstrated in two different types of correlators: the joint transform correlator and the classical convergent correlator. The proposed method is extended to the rotation-invariant and scale-invariant 3-D optical recognition. As is shown, the whole experimental setup can be constructed with simple equipment. Some experimental results, which demonstrate the ability of the method, are presented.