Back to results
US 6,463,162 B1Granted
Robust watermarking for digital objects
AssigneeHewlett-Packard Company
InventorPoorvi L. Vora
Life of this patent
Estimating the term…
Abstract
Method of embedding a watermark in a digital object. The watermark is used to perform argument modulation of a transform of the object. Watermark data is used in the argument of the transform to effectively shift around values in the transform domain.
Claims20
A method comprising the steps of:
- a) applying a transform to a digital object to generate a transformed digital object comprising a plurality of elements indexed by a first set of arguments;
- b) modulating the first set of arguments to selectively replace elements at selected locations within the transformed digital object with other elements from other locations within the transformed digital object to generate a watermarked transformed digital object;
- and
- c) performing an inverse transform of the watermarked transformed digital object to generate a watermarked digital object.
1 more element
A method comprising the steps of:
- a) transforming a digital object from a first domain f(il, . . .in) to a second domain F(kl, . . . kn);
- and
- b) modulating each argument of the transformed digital object to form a watermarked transformed digital object of the form G(ki, . . . . kn) wherein G(kl, . . .kn)=F(k1+λ1, . . . kn+λn), wherein λi=αi×wi(ki, . . .kn)−γ, wherein wi(kl, . . . .kn) corresponds to the watermark for each argument, ki.
A method of extracting a watermark embedded in a candidate digital object, comprising the steps of:
- a) applying a transform to each of an original digital object and the candidate digital object;
- b) modulating arguments of a selected one of the transformed original and candidate digital objects in accordance with modulation parameters;
- and
- c) identifying a resulting set of modulation parameters resulting in a minimum difference between the modulated transformed digital object and the other transformed digital object, wherein the resulting set of modulation parameters identify the watermark.
1 more element
Dependencies are inferred from the claim text.