METHOD FOR EMBEDDING MESSAGE INTO DOCUMENT, AND METHOD FOR EMBEDDING MESSAGE INTO DOCUMENT USING DISTANCE FIELD

摘要

PROBLEM TO BE SOLVED: To embed a message into a document according to a method that is inconspicuous and tolerant.

SOLUTION: A message 110 is embedded in a document 120 containing a set 125 of glyphs. Individual glyphs in the document 120, groups of glyphs in the document 120, or the entire document 120 are represented using a distance field that includes distance values from the shapes of interest. Each symbol 140 of a message 110 is represented as modifications of a subset 136 of the distance values in the distance field. This subset 136 of the distance values in the distance field is modified according to the modifications to produce a modified glyph 156 in a modified document 155, wherein the symbol in the message 110 is embedded in the modified glyph 156.

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