Method of watermark-embedding/extracting identification information into/from picture data and apparatus thereof, and computer readable medium
US6104826A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 9, 1997 |
| Grant date | Aug 15, 2000 |
| Priority date | — |
| Expiry date | Oct 9, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/327
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to methods for watermark-embedding/extracting identification information into/from picture data and apparatuses thereof. When identification information is watermark-embedded, the following steps are performed. Combinations of basis functions orthogonal each other are generated in association with each numerical signal. For each combination of the orthogonal basis functions, a weight coefficient is calculated so as to correspond to the combination of the basis functions by calculating a sum of products of values of the basis functions for pixels in the original picture data and pixel values of the pixels. For each numerical signal, a watermark-embedding function is referred, a input value is specified, and a pixel value is changed. When the identification information is extracted from the picture data, for each weight coefficient, the watermark-embedding function is referred, and the value of the watermark-embedding function is calculated for each weight coefficient.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.