Method for validating a document and method for determining the direction in which the document is fed

摘要

Random components for each characteristic amount of a paper type to be examined are extracted on the basis of characteristic amounts of the paper type which are read from a plurality of portions on the paper type and reference data previously found with respect to the plurality of portions. Dirt components for each of the plurality of portions on the paper type to be examined are presumed on the basis of the extracted random components for each characteristic amount and a predetermined forecast model of the dirt components. The truth of the paper type to be examined is judged on the basis of the presumed dirt components and the extracted random components. <IMAGE>