METHOD AND DEVICE FOR TESTING VALUE DOCUMENTS

摘要

The invention relates to a method and apparatus for recognizing forged value documents, for example composed forgeries which are assembled from parts of different value documents. In the inventive method, the signal intensity of a measuring signal is determined at a plurality of measuring points on a value document. For one or more selected groups of measuring points which are disposed in particular along certain directions on the value document there are determined gradient values of the signal intensities. The gradient values of a group are subsequently linked to form a connection strength of the group which provides a quantitative statement about the extent to which a large gradient value exists consistently within the particular group. From a relatively great connection strength there can be inferred the presence of a separating line in the area of the selected group of measuring points.