Programmable sensor aperture

摘要

A document to be verified or tested as a possible counterfeit is scanned by a system that optically senses a specific target area or aperture on the document. This area may include material deposited on the document or may be simply the document material. A reference grid is imprinted on the document to locate the same target area to be sensed each time the document is scanned, independent of the transport used to do the scanning. The reference grid is used to locate the target area both vertically and horizontally and signals sensed from the target area are combined to a representative composite.