Patent ID: 7757095

Claim:
A personal identification method for identifying a user by projecting an objective beam and a reference beam subjected to spatial light modulation in accordance with information to be recorded onto a holographic recording portion of an optical information recording medium having the holographic recording portion to record the information by interference fringes, and projecting a reproduction reference beam onto the interference fringes to reproduce the object beam, the method comprising: subjecting the reference beam to the spatial light modulation by record cryptographic identification information based on biometric information of the user when recording the information, subjecting the reproduction reference beam to the spatial light modulation by validation cryptographic identification information based on biometric information directly obtained from the user when reproducing the information, imaging the biometric information by a predetermined encoding scheme, forming the record cryptographic identification information and the validation cryptographic identification information, and this image is used as a modulation pattern of the reference beam and the reproduction reference beam, wherein the encoding scheme comprises the steps of: dividing an original image displaying the biometric information into a plurality of pixel blocks, said pixel blocks being composed of a plurality of and the same number of pixels, and detecting and counting the number of ON pixels or OFF pixels in each pixel block; and converting the pixels of each pixel block into a corresponding one of a plurality of predetermined conversion pixel patterns based on the counted number of ON pixels or OFF pixels in order to provide a bitmap image indicating the record cryptographic identification information and the validation cryptographic identification information; and wherein each pixel block is composed of an even number equal to or more than six of pixels, and each conversion pixel pattern has the same number of ON pixels and OFF pixels.