05396559 is referenced by 179 patents and cites 8 patents.

A security device for use on identification cards, monetary documents, and the like using a reference pattern and a message pattern each having the appearance of a random pattern of dots. The reference pattern is a dense pattern of randomly positioned dots, and the message pattern is a modulated version of the reference pattern in which the dots of the reference pattern are slightly repositioned by an amount depending on the grey value or color value of a message image at each dot location. The message image is decrypted and becomes visible with a range of grey values when it is viewed through a film transparency of the reference pattern. The dot pattern may be printed, embossed or recorded as a photograph or a hologram. Decryption of the message image may be accomplished by viewing through a contact mask, superposition of images of the message pattern and reference pattern, by viewing the message pattern through a mask positioned at a real image of the reference pattern, or like means.

Anticounterfeiting method and device utilizing holograms and pseudorandom dot patterns
Application Number
Publication Number
Application Date
August 24, 1990
Publication Date
March 7, 1995
Stephen P McGrew
149-B Josephine St., Santa Cruz, 95060
Wells St John Roberts Gregory & Matkin
G09C 5/00
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