Encoding technique of data patterns to improve signal-to-noise ratio during content-addressable retrieval

摘要

A content-addressable optical storage system in which a first beam of light is modulated an image to-be-stored and directed to a storage location in an optical storage medium. The image to-be-stored has a plurality of pixels representing at least one field of digital data that are selectively organized along a selected data track as a pattern of ON and OFF pixels representing a data value by a position of a block of pixels of a predetermined size on the data track. A second beam of light, which is coherent with the first beam of light, is modulated with a predetermined modulation pattern and directed to the storage location. The second beam of light passes through the optical storage medium and is focussed at a plurality of localized portions of a correlation plane in the predetermined modulation pattern. The image to-be-stored in the storage medium is recorded at the storage location medium based on an intersection of the first beam and the second beam in the optical storage medium. Optical correlation is provided by blocking the second beam of light, and modulating a third beam of light an image to-be-correlated and that is directed to the optical storage medium. At least one set of reconstructed correlation peaks are detected at the correlation plane matching the modulation pattern of the second beam of light. A brightness of the set of detected reconstructed correlation peaks indicates a similarity between the image to-be-correlated and a stored image.