Phase filter multiplexing for pattern recognition process

Usually filters used in optical correlators are holograms, digitally or optically synthesized, that store the phase information of the objet by encoding it in an amplitude media. The impulse response produced by these kinds of filters presents, beside the image of the object, the conjugate one. Thus, the number of channels available in the correlation plane is reduced. We present here a method to directly store the phase information of the objects in a liquid crystal television display working in phase-only mode. In that way the conjugate image of the object is not present in the impulse response of the filter. We introduce two different types of composed filters and compare the results obtained experimentally and by numerical simulation.