Three dimensional(3-D) object recognition with rotation-invariant

An automatic method for rotation-invariant three-dimensional (3-D) object recognition is proposed. The method is based on the use of 3-D information contained in the deformed fringe pattern obtained when a grating is projected onto an object's surface. Since the deformed fringe pattern contains the height information of object, the method has the characteristic of intrinsic 3-D recognition. The rotation invariance is achieved by using the multi-channel phase-only filter. The filter is composed of deformed fringe patterns of the same object at different angle. The proposed method can be optically implemented by means of VanderLugt optical correlator. Experimental results show the utility of the proposed method and its ability to estimate the rotational angle of the objects.