Digital watermark embedding apparatus, digital watermark extraction apparatus, and methods thereof
US7209572B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 9, 2003 |
| Grant date | Apr 24, 2007 |
| Priority date | — |
| Expiry date | Oct 12, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0062
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A document image undergoes document analysis to obtain circumscribing rectangles of characters (S601), and two distances between non-neighboring circumscribing rectangles from the head of the document are respectively calculated as d1 and d2 (S603). If information to be embedded is 1, one or a combination of a process for changing a parameter associated with the size of a circumscribing rectangle and a process for changing a parameter associated with the position of a circumscribing rectangle is executed to satisfy d1>d2 (S605). If information to be embedded is 0, one or a combination of the above two parameter change processes is executed to satisfy d1<d2 (S606).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.