Watermark embedding and detection of a motion image signal
US7844072B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 13, 2004 |
| Grant date | Nov 30, 2010 |
| Priority date | — |
| Expiry date | Aug 3, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0051
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Methods and arrangements are disclosed for embedding and detecting a watermark in a cinema movie, such that the watermark can be detected in a copy made by a handheld video camera. The watermark embedder divides each image frame into two areas. A watermark bit ‘+1’ is embedded in a frame by increasing the luminance of the first part and decreasing the luminance of the second part. A watermark bit ‘−1’ is embedded by decreasing the luminance of the first part and increasing the luminance of the second part. It is achieved with the invention that the embedded watermark survives ‘de-flicker’ operations that are often used to remove flicker caused by the different frame rates of cinema projection equipment and consumer camcorders.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.