Media and methods employing steganographic marking
First Claim
1. A substrate useful in forming a printed object, characterized in that the substrate has been marked to encode a steganographic digital watermark pattern thereon that conveys plural bits of digital information, said marking not being apparent to a human observer of the printed object, said steganographic pattern being detectable by visible-light scanning of the printed object to yield data from which the plural bits of digital information can be recovered, wherein said plural bits of digital information correspond to the digital watermark pattern in accordance with an algorithmic transformation, and the marking comprises a speckling of ink dots.
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Accused Products
Abstract
Stationery, or other printable media, is encoded with a digital watermark. The watermark is not conspicuous to a human observer of the media, yet conveys plural bits of auxiliary information when optically scanned and digitally processed. The watermark can be formed by ink-jet printing, or otherwise. The encoded information can be used for various purposes, including authenticating the document as an original, linking to associated on-line resources, and distinguishing seemingly-identical versions of the same document (document serialization).
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Citations
23 Claims
- 1. A substrate useful in forming a printed object, characterized in that the substrate has been marked to encode a steganographic digital watermark pattern thereon that conveys plural bits of digital information, said marking not being apparent to a human observer of the printed object, said steganographic pattern being detectable by visible-light scanning of the printed object to yield data from which the plural bits of digital information can be recovered, wherein said plural bits of digital information correspond to the digital watermark pattern in accordance with an algorithmic transformation, and the marking comprises a speckling of ink dots.
- 20. A method of processing a blank substrate prior to formation of a printed object, the method comprising encoding the substrate with a steganographic digital watermark pattern that does not impair subsequent use of the substrate, yet conveys plural-bit digital information, said pattern not being apparent to a human observer of the printed object, said steganographic pattern being detectable by visible-light scanning of the printed object to yield data from which the plural bit digital information can be recovered, wherein said plural bits of digital information correspond to the digital watermark pattern in accordance with an algorithmic transformation.
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22. A method comprising:
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applying an algorithmic transformation to plural bits of digital information to generate pattern data corresponding thereto; marking a substrate with dots of ink to encode a steganographic pattern thereon corresponding to said pattern data; wherein said marking is not apparent to a human observer of the marked substrate, but the plural bits of digital information are decodable from visible light scan data captured from the marked substrate. - View Dependent Claims (23)
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Specification