Patent ID: 7574033

Claim:
A sheet paper identification device that images an image of sheet paper by means of an image pickup section located on a feed path for the sheet paper and identifies the sheet paper on the basis of image data of the sheet paper thus imaged and acquired, comprising: image data acquisition means for acquiring sheet-paper-absent image data imaged and acquired by the image pickup section in a state where sheet paper has not yet arrived at the image pickup section and there is no sheet paper, and sheet-paper-present image data imaged and acquired in a state where sheet paper has arrived at the image pickup section and there is the sheet paper; measurement means for measuring a position and area of an image in the sheet-paper-absent image data acquired by the image data acquisition means; unwanted image discrimination means for discriminating an image that exists in the sheet-paper-present image data in the same position and over the same area as the image in the sheet-paper-absent image data measured by the measurement means as an unwanted image; and sheet paper identification means for attaching the unwanted image discriminated by the unwanted image discrimination means to standard data found beforehand from genuine sheet paper in the same position and over the same area as the unwanted image, and identifying the authenticity of the sheet paper by comparing the standard data to which the unwanted image is attached with the sheet-paper-present image data.