Digital watermark embedding apparatus for document, digital watermark extraction apparatus for document, and their control method
US7106884B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 2003 |
| Grant date | Sep 12, 2006 |
| Priority date | — |
| Expiry date | Feb 20, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0062
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
This invention provides a digital watermark embedding apparatus for a document, which can eliminate unnaturalness that may be experienced upon laying out characters in a document when watermark information is embedded, while maintaining the robustness of a document itself and the information size to be embedded of a digital watermark. A document image is input from an image input unit (11), and watermark information is input from a watermark information input unit (15). A region division unit (12) divides the document image into regions, and a circumscribing rectangle extraction unit (13) sets circumscribing rectangles for characters and extracts them as character images. A punctuation mark determination unit (14) determines a punctuation mark from the character image. A watermark information embedding unit (16) embeds watermark information by digital watermarking that shifts character images other than the character image determined to be a punctuation mark.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.