Patent ID: 8107145

Claim:
A reproducing device for performing reproduction regarding a hologram recording medium in which a hologram page is recorded in accordance with signal light, by interference between said signal light in which bit data is arrayed with the information of light intensity difference in pixel increments, and reference light, said reproducing device comprising: reference light generating means configured to generate said reference light to be irradiated when obtaining a reproduced image regarding said hologram page recorded in said hologram recording medium; coherent light generating means configured to generate coherent light of which the intensity is greater than the absolute value of the minimum value of the amplitude of said reproduced image, and the phase becomes the same phase as the reference phase within said reproduced image; an image sensor configured to receive an input image in pixel increments to obtain an image signal; an optical system configured to guide said reference light to said hologram recording medium, and also guide said reproduced image obtained from said hologram recording medium according to the irradiation of said reference light, and said coherent light to said image sensor, wherein the number of pixels of said image sensor side, and said optical system are adjusted such that an over-sampling rate representing a ratio regarding whether to receive the image of one data pixel worth representing the information of one data bit worth within said reproduced image at the region of how many pixels worth of said image sensor side is greater than at least one; square root calculating means configured to input an image signal obtained based on light-receiving operation by said image sensor to calculate the square root of each value making up said image signal; removing means configured to remove the components of said coherent light from an image signal serving as the square root calculation result by said square root calculating means; pixel position identifying means configured to identify the position of each data pixel included in said reproduced image from an image signal after removal processing by said removing means; pixel amplitude value obtaining means configured to obtain the amplitude value at each data pixel position within said image signal based on the information of the position of each data pixel identified by said pixel position identifying means; and reproducing means configured to reproduce recorded data based on the amplitude value at each data pixel position obtained by said pixel amplitude value obtaining means.