Method and apparatus for determining authenticity

摘要

In an authenticity determining apparatus, an image-data acquiring unit acquires image data of a paper sheet; a block-value calculating unit divides the image data into a plurality of blocks each composed of a plurality of pixels and calculates a block value of each of blocks; an average-block-value calculating unit calculates an average block value of blocks composing a predetermined area of the image data; a correction-block-value calculating unit calculates a corrected block value of each of the blocks by correcting each of the block values so that the average block value is equal to a predetermined reference value; and an authenticity determining unit that determines authenticity of the paper sheet based on whether each of corrected block values of the blocks composing the predetermined area is within a predetermined allowable numerical range that is preliminarily defined for the predetermined area.