Method and apparatus for video watermarking
US6546113B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1999 |
| Grant date | Apr 8, 2003 |
| Priority date | — |
| Expiry date | Mar 2, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0051
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Watermark data consisting of known two-dimensional codeword patterns are added to a first portion of each video frame by modifying parameters defining the first portion. Limited randomization of the spatial position of the codeword pattern is also provided. During a decoding process, a predictor continuously estimates the current value of the modified parameters. In one embodiment of the present invention, the predictor employs video samples taken from unmodified areas of the frame to provide the estimates. The estimated parameter values are subtracted from the actual parameter values to provide an error signal. Multiple correlators attempt to detect the presence of the codeword pattern in the error signal within a range of spatial locations surrounding a nominal position of the codeword pattern. The use of multiple correlators provides immunity to feasible attacks aimed at damaging or obscuring the watermark.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.