Patent ID: 7623279

Claim:
A method for use with a storage medium that holographically stores information, the method comprising the following steps: (a) generating a reconstructed data beam by directing a first coherent light beam into a storage medium, wherein the first coherent light beam reproduces a reference beam used to holographically store information in the storage medium; (b) obtaining a first image from a first combined beam produced by combining at least a portion of the reconstructed data beam with at least a portion of second coherent light beam, wherein the reconstructed data beam and the second coherent light beam have a phase difference that is a first phase difference; (c) obtaining a second image from a second combined beam produced by combining the reconstructed data beam with the second coherent light beam, wherein the phase difference of the reconstructed data beam and the second coherent light beam has been adjusted to produce a second phase difference; (d) processing the first image and second image to obtain first image contrast information and second image contrast information; (e) obtaining combined information from the first image and second image using the first image contrast information and the second image contrast information; and (f) processing the combined information to obtain the information holographically stored by the storage medium.