| 摘要 |
PROBLEM TO BE SOLVED: To prevent forgery and alteration by performing recording onto an optical recording medium while providing a recording part and an erasing part for a hologram pattern so that a combinational code composed of binary codes can correspond to the recording part and erasing part for the hologram pattern. SOLUTION: The information of binary codes, to which combinational coding is performed, is recorded on an optical recording medium 1 corresponding to the erasure/non-erasure of a hologram image. Every information, to which combinational coding is performed, is recorded by the erasure/non-erasure of plural holograms 2 in a group allocated for every information. As an erasing method for holograms 2, they are erased by a thermal head 3. The light of LD is reflected on the hologram 2, its image is received by an imaging device, and information is provided by judging the non-erasure/erasure of the hologram 2 corresponding to the presence/absence of the desired hologram image. In alteration analysis, the imaging device comprehends the presence/absence of the hologram image as binary codes and when the combinational code is formed as ruled, the absence of alteration is judged. |
