Digital watermarking in a perceptually uniform domain
US6792129B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2000 |
| Grant date | Sep 14, 2004 |
| Priority date | — |
| Expiry date | Mar 5, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0202
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Methods and apparatus for watermarking a digital media object, and for detecting watermarks, are presented. The basic concept underlying the disclosed approach is watermarking/detection in a transform space that allows the same level of watermarking to be applied to all samples. For instance, in one embodiment, a watermarking system first nonlinearly transforms the original signal to a perceptually uniform domain, and then embeds the watermark in this domain without varying the statistical properties of the watermark at each sample. At the watermark detector, a candidate image is transformed to the same perceptually uniform domain, and then correlated with the original watermark sequence. Under such conditions, it is shown that an optimal watermark detector can be derived. This approach is particularly attractive when the original image is unavailable at the detector, as it effectively prevents the image content from biasing the watermark detection score.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.