Embedding and detection of watermark in a motion image signal
US8452971B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 22, 2011 |
| Grant date | May 28, 2013 |
| Priority date | — |
| Expiry date | Jul 22, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0051
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A video watermarking scheme is disclosed, which is designed for the digital cinema format, as it will be used on large projector screens in theaters. The watermark is designed in such a way that it has minimal impact on the video quality, but is still detectable after capture with a handheld camera and conversion to, for instance, VHS, CD-Video or DVD format. The proposed watermarking system only exploits the temporal axis. This makes it invulnerable to geometrical distortions generally caused by such a way of capturing. The watermark is embedded by modulating a global property of the frames (e.g. the mean luminance) in accordance with the samples of the watermark. The embedding depth is preferably locally adapted within each frame to local statistics of the respective image. Watermark detection is performed by correlating the watermark sequence with extracted mean luminance values of a sequence of frames.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.