PROBLEM TO BE SOLVED: To perform at high speed, authenticity determination processing which is performed based on an image of an authenticity determination object.;SOLUTION: An authenticity determination method is configured to: acquire images of an authenticity determination object in which there is a pattern whose outside is a prescribed color circle (step S101); detect a reference image position where the prescribed color circle is detected first, by scanning acquired images in a prescribed order (step S102); determine a circle center position of the circle on the basis of the detected reference image position and a radius of the circle (step S103); determine average density for plural doughnut-state data surrounded by concentric circles having a different radius respectively and having the circle center position as a circle center, and calculate density distribution in which the average densities are arranged in the radius direction (step S104); and compare reference density distribution for determination which has been determined in advance, with the density distribution, for performing authenticity determination of the authenticity determination object (steps S105-S108).;SELECTED DRAWING: Figure 9;COPYRIGHT: (C)2017,JPO&INPIT
展开▼
