Image dissecting document verification system

A verification system for documents bearing machine-readable identification indicia subject to alteration by wear damage or counterfeiting and related to an accessible memory, comprising:

• means for reading said indicia to provide representative pixel test signals for an array including at least part of said indicia;
• means for providing representative pixel reference signals for said array from said accessible memory;
• means for correlating said test signals and said reference signals pixel-to-pixel to provide correlation signals;
• display means controlled by said correlation signals for indicating the locations of specific areas of said document for which said pixel test signal fails to correlate with said pixel reference signal, thereby enabling an operator in visually determining whether those specific areas of said documents indicated by said display means have been tampered with or said documents have merely been subject to wear and tear;
• and
• means for enabling detailed display of said correlation signals on a subpixel-to-subpixel basis.