Authentication system for authenticating hidden image or concealment information, authentication method, and authentication program

摘要

PROBLEM TO BE SOLVED: To provide an authentication method and an authentication system capable of performing character recognition by decoding an invisible image by moving a reference point of reduction processing and performing reduction processing on an original image photographed using a commercially available imaging device, and acquiring a difference image from the original image.;SOLUTION: An authentication terminal reduces an original image at a predetermined reduction ratio with reference to a reference point in a photographed image, and generates a reduced image; enlarging the reduced image at an enlargement ratio which is the inverse of the reduction ratio with reference to the reference point, performing interpolation processing to make the number of pixels of the enlarged image the same as that of the original image, and generating an enlarged image; subtracting a luminance value of each pixel of the original image from a luminance value of each pixel of the enlarged image, and generating difference image data; separating a background region and a character region from the difference image data and shifting the reference point to a predetermined direction by pixel units; collating the character region extracted from the difference image data with a character pattern, performing OCR, and authenticating a concealed image or concealed information.;SELECTED DRAWING: Figure 45;COPYRIGHT: (C)2020,JPO&INPIT