Digital information embedding/extracting apparatus and method, and medium including a program for executing the method recorded thereon
US6788821B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2001 |
| Grant date | Sep 7, 2004 |
| Priority date | — |
| Expiry date | Feb 9, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0061
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an embedding apparatus, a transform section divides an original image into a plurality of blocks to perform orthogonal transform every block. An embedding section embeds a pseudo-random number sequence mapped with inherent digital information in part of a transform coefficients sequence obtained by the orthogonal transform using a weight sequence. In an extracting apparatus, a calculation section reads transform coefficients sequences for respective blocks from the data including the pseudo-random number sequence embedded therein in a predetermined order, and calculates an inner product between the transform coefficients sequences and a pseudo-random number sequence. A determination section determines that the pseudo-random number sequence has been embedded when the inner product is greater than a predetermined threshold value. A generation section extracts inherent digital information mapped with the determined pseudo-random number sequence. This method discourages deciphering of the digital information, suppresses image quality deterioration, and improves the detection rate of watermark data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.