Method of encoding data in a monochrome media

摘要

A method for encoding data in a monochrome media utilizing the capability of the media for grayscale resolution. A document is processed to provide an image in electronic format, in which each pixel has an assigned data value with a given bit depth. A mapping operation is performed for generating a monochrome data word ( 120 ), preferably having a reduced bit depth. The monochrome data word ( 120 ) can be used to encode multiple data fields ( 114, 116, 118 ). A printer ( 92 ) then produces a preserved document record ( 90 ) in which the appropriate monochrome data word ( 120 ) determines the grayscale value for each pixel.