Patent ID: 6394358
Filing Date: 2002-05-28
Classification: B41M,G07D

Abstract:
A device for authenticating a security document, said security document including a security image printed on a face thereof, wherein said security image is defined by a collection of security image elements, wherein said security image defines at least one document authentication scheme, and wherein said document authentication scheme is arranged to provide a primary indication of document authenticity, said authentication device comprising:an optical imaging device arranged to generate a security image signal representative of at least a portion of said security image; and a controller programmed to define an authentication constellation within said security image, wherein said authentication constellation defines a set of constellation pixels, and wherein said constellation pixels are arranged at predetermined coordinates within said security image; identify respective occupation characteristics of each of said constellation pixels based on said security image signal, wherein each of said respective occupation characteristics represents a degree of printed matter within a selected constellation pixel; and determine whether said respective identified occupation characteristics correspond to an authentic document by comparing said respective identified occupation characteristics to a set of authentic occupation characteristics.