Methods and sytems using multiple watermarks
First Claim
1. A method of determining whether a document is likely an original document, the document comprising a first steganographic watermark and a second steganographic watermark, said method comprising:
- reading a first characteristic related to the first steganographic watermark;
reading a second characteristic related to the second steganographic watermark;
reading a third characteristic related to the document'"'"'s physical condition; and
with reference to the first, second and third characteristics, assessing whether the document is likely an original document.
6 Assignments
0 Petitions
Accused Products
Abstract
Two or more digital watermarks, with different characteristics, are embedded in a document. The characteristics are chosen so that the watermarks will be affected in different manners if the document is subsequently copied or reproduced. The detection process or mechanism reads two or more of the watermarks and compares their characteristics. While wear and handling may change the characteristics of the digital watermarks in a document, the relationship between the characteristics of the multiple digital watermarks in a document will nevertheless give an indication as to whether a document is an original or a copy of an original. Document wear can be independently assessed and used as an aid in interpreting the detected watermark characteristics.
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Citations
13 Claims
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1. A method of determining whether a document is likely an original document, the document comprising a first steganographic watermark and a second steganographic watermark, said method comprising:
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reading a first characteristic related to the first steganographic watermark;
reading a second characteristic related to the second steganographic watermark;
reading a third characteristic related to the document'"'"'s physical condition; and
with reference to the first, second and third characteristics, assessing whether the document is likely an original document. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for determining whether a printed object is likely an original printed object, the printed object comprising at least a first digital watermark and a second digital watermark, said method comprising:
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detecting a first characteristic related to the first digital watermark;
detecting a second characteristic related to the second digital watermark; and
comparing the first characteristic and the second characteristic to determine whether the printed object is likely an original printed object. - View Dependent Claims (8, 9, 10, 11, 13)
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12. A document including a substrate with printing thereon, the printing comprising at least a first steganographic watermark and a second steganographic watermark, the first steganographic watermark comprising a first characteristic and the second steganographic watermark comprising a second characteristic, wherein the first and second characteristics are affected in a different manner when the document is subjected to a first corruption process and a second corruption process.
Specification