Patent ID: 7675664

Claim:
An apparatus for reproducing data from a recording medium, said apparatus comprising: a first reproducing reference beam source configured to apply a first reproducing reference beam to said recording medium at a first angle; a second reproducing reference beam source configured to apply a second reproducing reference beam to said recording medium at a second angle, wherein said recording medium includes a first element hologram formed by interference fringes generated by interference between a first data object beam and a first recording reference beam applied at the first angle, and a second element hologram formed on the recording medium by interference fringes generated by interference between a second data object beam and a second recording reference beam applied at the second angle, the second angle being different from the first angle, and the second element hologram partly overlapping the first element hologram; a reproduced image detecting section configured to detect hologram images reproduced from said recording medium irradiated with the reproducing reference beams and outputting reproduced image signals representing said hologram images, wherein each of said reproduced image signals representing adjacent element holograms which are disposed in an overlapping relation have a first identifier and a second identifier; an identifier detecting section configured to detect the first identifier and the second identifier in each of said reproduced image signals, to generate a first identifier signal from successive first identifiers detected by the identifier detecting section, and to generate a second identifier signal from successive second identifiers detected by the identifier detecting section; a comparator configured to determine a difference between the first identifier signal and the second identifier signal; a signal reading section configured to read the reproduced image signals representing said hologram images detected by said reproduced image detecting section, and to store the reproduced image signal in a memory device; a timing detecting section configured to detect scanning times for scanning the element holograms recorded in said recording medium from the reproduced image output from said reproduced image detecting section when said recording medium is irradiated with the reproducing reference beams at one of said first angle and said second angle; and a control section configured to control each of said first and second reproducing reference beam sources to apply the reproducing reference beams at the respective angles corresponding to the element holograms at the scanning times detected by said timing detecting section based on the difference between the first identifier signal and the second identifier signal, and controlling said reproduced image detecting section to detect and reproduce said hologram images from said recording medium in response to the applied reference beams.