METHOD AND DEVICE FOR DETECTING COLOR FADING ON A VALUE DOCUMENT, IN PARTICULAR A BANKNOTE, AND VALUE-DOCUMENT PROCESSING SYSTEM

摘要

The invention relates to a method for detecting color fading on a value document, in particular a banknote, on the basis of a captured image (4) of the value document, which image has a plurality of pixels, each pixel being assigned at least one intensity value (P_i), wherein the following steps are performed for each pixel of a selection of pixels of the image (4): determining an intensity value, in particular a mean, from intensity values (P₀ - P₈) assigned to the pixel and to pixels near the pixel; calculating a contrast value on the basis of intensity values (P₀ - P₈) assigned to the pixel and to pixels near the pixel; and classifying the pixel with respect to color fading of the value document (1) in accordance with the determined intensity value, in particular mean, and the calculated contrast value. The invention further relates to a corresponding device and to a value-document processing system.