Patent ID: 6868173

Claim:
A method of judging the truth of a paper type, comprising the steps of: measuring, with respect to each of true paper types previously prepared, a plurality of types of characteristic amounts by a plurality of types of sensors for each of a plurality of portions for examination previously determined, analyzing principal components on the basis of obtained results of the measurement, to find an equation of a straight line corresponding to a predetermined principal component, wherein the equation of the straight line for the predetermined principal component is calculated through a sum of squares of the obtained results, and producing reference data composed of a value relating to the predetermined principal component for the portion for examination on the basis of the found equation of straight line; measuring, with respect to the paper type to be examined, the plurality of types of characteristic amounts by the plurality of types of sensors for each of the plurality of portions for examination previously determined, and producing data for examination composed of a value relating to the predetermined principal component for the position for examination on the basis of obtained results of the measurement and said equation of straight line; and comparing the reference data and the data for examination, to judge the truth of the paper type to be examined.