Patent ID: 6970235

Claim:
A method of inspecting documents of value, the method comprising moving a document past a document monitoring system, the document monitoring system: a) obtaining images of one or more parts of the document from radiation received from that part or those parts of the document in respective different wavelength bands by using a document monitoring system comprising illumination apparatus for illuminating a region, at which part of the document is located in use, with radiation in at least two different wavelength bands; and detection apparatus for detecting any of said radiation which is reflected by or transmitted through substantially the same said part of the document and for generating corresponding output signals; b) performing an analysis of one of said images to identify a first type of class within which the document is included; and c) performing an analysis of another of said images using corresponding predetermined data relating to members of the first type of class identified in step b) so as to determine a second type of class within which the document of value is included.