Patent ID: 6606396
Filing Date: 2003-08-12
Classification: G06K

Abstract:
A method of determining whether or not a medium on which a two-dimensional code and a predetermined figure pattern are printed is counterfeit, wherein an error in the two-dimensional code is correctable during decoding of the two-dimensional code, and a cell position corresponding to a position of the error is detectable, the predetermined figure pattern being made of special ink, the two-dimensional code and the predetermined figure pattern overlapping each other at a specified place in the medium, the method comprising:optically reading the two-dimensional code from the medium; decoding the two-dimensional code which has been optically read for obtaining decoding results, wherein the decoding of the two-dimensional code includes performing an error correction process on the decoding results and detecting an error correction position that is the position of the error and the cell position corresponding to the position of the error when an error is detected in the decoding results; determining whether or not the detected error correction position is in the specified place; and judging whether or not the medium is counterfeit in response to a result of the determining of whether or not the detected error correction position is in the specified place.