Binary zone-plate array for a parallel joint transform correlator applied to face recognition

Taking advantage of small aberrations, high efficiency, and compactness, we developed a new, to our knowledge, design procedure for a binary zone-plat e array (BZPA) and applied it to a parallel joint transform correlator for the recognition of the human face. Pairs of reference and unknown images of faces are displayed on a liquid-crystal spatial light modulator (SLM), Fou rier transformed by the BZPA, intensity recorded on an optically addressabl e SLM, and inversely Fourier transformed to obtain correlation signals. Con sideration of the bandwidth allows the relations among the channel number, the numerical aperture of the zone plates, and the pattern size to be deter mined. Experimentally a five-channel parallel correlator was implemented an d tested successfully with a 100-person database. 20-channel BZPA for phone tic character recognition are also included. The design and the fabrication of a (C) 1999 Optical Society of America.