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. The proposed method was optically implemented by means of a two-cycle joint transform correlator. The rotation invariance is achieved by means of encoding with the fringe pattern a single component of the circular-harmonic expansion derived from the target. Thus the method is invariant for rotations around the line of sight. The whole experimental setup can be constructed with simple equipment. Experimental results show the utility of the proposed method.
© 2000 Optical Society of America
José J. Esteve-Taboada, Javier García, and Carlos Ferreira, "Rotation-Invariant Optical Recognition of Three-Dimensional Objects," Appl. Opt. 39, 5998-6005 (2000)