Authenticity determination method, and authenticity determination apparatus of the recording medium composed of a diffraction grating pixel

摘要

PPROBLEM TO BE SOLVED: To provide an authenticity determination method and an authenticity determination apparatus that achieve accurate authenticity determination without limiting an irradiation position of a laser beam. PSOLUTION: The authenticity determination method, for determining authenticity of a recording medium M in which a pattern is expressed by two-dimensionally and regularly arranging pixels comprising diffraction gratings, is configured as follows: a plurality of sampling positions of the recording medium M are successively irradiated with a laser beam 6, having a cross-sectional area smaller than an area of the recording medium M; diffracted-light pattern images, obtained by corresponding to the sampling positions, are imaged by an imaging means 5; and a plurality of the obtained diffracted-light pattern images are superposed and overlapped so as to form a composite pattern image. By determining whether the obtained composite pattern image matches the previously-prepared determination criteria, the recording medium M is determined to be authentic or counterfeit. PCOPYRIGHT: (C)2010,JPO&INPIT