To provide a method for extracting feature value from the picture data of a medium without being influenced by the expansion of the medium or the variation of the carrying speed.
The coordinates 2 of the center are found out from the contour of picture data 1 of a bill medium and set up as the coordinate origin of a center coordinate system. The coordinates 3 to 6 of four corners are set up as the coordinate origins of a four-corner coordinate system. Since the center coordinate system is not almost influenced by the expansion or the like of a bill, coordinates around the origin can be accurately found out. Since the four-corner coordinate system can be found out from an intersection between a minor side and a major side even when a corner of picture data is lost by the fold of the corner of a bill, a reliable coordinate value prevented from being influenced by the expansion or the like of the bill can be obtained. A featured value extraction area is found out by using the center coordinate system for the vicinity of the center of the bill and using the four-corner coordinate system for four corners and feature values consisting of the average, dispersion, maximum and minimum values of pixel values are found out from the area.
MATSUMOTO HARUYUKI
KADOSAKI TOYOSHI
FURUI TATSUYA
