PRINTED MEDIUM INSPECTION SYSTEM USING IMAGE PROCESSING, AUTHENTICITY DETERMINATION METHOD FOR PRINTED MEDIUM, AND IMAGE PICKUP APPARATUS THEREFOR

摘要

A first pattern (27a) printed in a first ink containing an infrared-absorbing pigment and a colour-changing pigment and a second pattern (27b) printed in a second ink containing an infrared-reflecting pigment and a colour-changing pigment are printed on the surface of an authentic printed medium (2), a plurality of first images of the surface of a printed medium are picked up while changing the irradiation angle of a source of visible light, as well as a plurality of second images of the surface of the printed medium being picked up while changing the irradiation angle of a source of infrared light, all of the image data is compared with data corresponding to the first pattern and the second pattern, and the print medium is determined to be authentic when data corresponding to the first pattern and data corresponding to the second pattern are present in one part of the first image data, and when data corresponding to the first pattern is missing from and data corresponding to the second pattern is present in one part of the second image data, or when data corresponding to the second pattern is missing from and data corresponding to the first pattern is present in one part of the second image data.