Watermark information embedding apparatus, image processing device, watermark information embedding method and image processing method

摘要

A watermark information embedding apparatus capable of embedding a plurality of different types of information together in a document is provided. In a pattern table 19, (1) a permanent dot pattern which is to remain after a document is copied and (2) a temporary dot pattern which is to be erased as the document is copied, are both allocated to each of symbols constituting confidential information and they are classified and managed as hyper-complex matrices. A watermark image is formed based upon anti-copy information used to determine whether the permanent dot pattern or the temporary dot pattern is to be set. Since this allows both the anti-copy information and the confidential information to be embedded together in the document, duplication of the document containing the confidential information embedded therein can be deterred.