Data processing apparatus and method
US7609849B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2005 |
| Grant date | Oct 27, 2009 |
| Priority date | — |
| Expiry date | Oct 18, 2027 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0083
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method includes generating, for a signal sample, first and second gaussian likelihood functions describing a likelihood of a watermark codeword coefficient value embedded into the signal sample being, respectively, positive and negative. The first gaussian likelihood function has a mean defined by a sum of a local mean value and a watermark strength value and a standard deviation defined by a local standard deviation. The second gaussian likelihood function has a mean defined by a difference between the local mean value and the watermark strength value and the standard deviation defined by the local standard deviation. The method also includes detecting a watermark in an image signal based on a probability of watermark codeword coefficients added to the signal sample being one of positive or negative, the probability being calculated from the first gaussian likelihood function and the second gaussian likelihood function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.