Method and apparatus for making and detecting a document verification indicator using optical pattern encryption

Abstract

A method and apparatus for creating and detecting an optically encoded document having a uniquely designed document verification indicator is disclosed. One embodiment includes applying a spatially varying Brewster angle pattern on a substrate. Another embodiment includes an apparatus for detecting the spatially varying Brewster angle pattern including a light source, a slit aperture, a polarizer, at least one parabolic mirror, and an image capturing device.

1 . A document verification indicator comprising an optical pattern of spatially varying refractive index values. 
     
     
         2 . The document verification indicator of  claim 1 , wherein the pattern comprises a spatially varying Brewster angle pattern. 
     
     
         3 . The document verification indicator of  claim 1 , wherein the pattern comprises an optically encoded user recognizable authentication code. 
     
     
         4 . The document verification indicator of  claim 1 , wherein the pattern is transparent. 
     
     
         5 . The document verification indicator of  claim 1 , wherein the pattern is detectable using a bi-directional image capturing system. 
     
     
         6 . The document verification indicator of  claim 1 , wherein the pattern is applied to a substrate using ink jet printing.