Fast associative filtering based on two-dimensional discrete Walsh transform by a volume holographic correlator

An optical fast associative filtering method based on a multi-channel volume holographic correlator to search the database as a front-end filter is described. The features of searching query are parallelly extracted by a volume holographic correlator based on two-dimensional discrete Walsh transform, and are used to measure the similarity between the query and all the database records. The best matches are picked up for further searching. An experiment is carried out, and the experimental results prove the validity of the method.