Method for embedding and extracting a spatial domain blind watermark using sample expansion
US7006659B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 2002 |
| Grant date | Feb 28, 2006 |
| Priority date | — |
| Expiry date | Jul 29, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/3281
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method for embedding and extracting a spatial domain blind watermark using a sample expansion. The sample expansion method using a sample expansion coefficient is introduced to basically improve a common disadvantage of the conventional watermarking method based on the patchwork method, for instance, the watermark is not robust against a compression attack such as JPEG. By applying the sample expansion to a sample group, the embedded watermark comes to contain a low frequency component more larger than ever, so that radio frequency component decreases as much. Thus, although the radio frequency component of the watermark is damaged by the image compression such as JPEG, it is possible to relatively reduce the damage of the watermark. Also, an adaptive watermark embedding method can be considered such that the embedded watermark value is proportional to an average value of the pixel. In order to overcome non-robustness that is a common disadvantage of the conventional methods based on the conventional patchwork method or the conventional modified patchwork method, not a single pixel but sample-expanded pixel is chosen, and there is proposed a spatial domain blind wate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.