Image processing machine capable of inhibiting copying of valuable papers

摘要

An image processing machine having an electrophotographically making copies of one or more originals. This image processing machine is designed to inhibit the electrophotographic copying function in the event that one attempts to make a copy of valuable papers such as monetary papers or securities and comprises a detecting unit for detecting a spatial frequency of a small region of an original to be copied, a calculating unit for comparing the detected spatial frequency with a standard spatial frequency used as a standard pattern, thereby to calculate the degree of similarity therebetween, a judging unit for judging whether or not the degree of similarity so calculated is greater than a predetermined value, and a determining unit for determining, when the judging unit indicates the degree of similarity greater than the predetermined value, that the original to be copied is identical with an original used as a basis for the standard pattern.