Multiple watermarking techniques for documents and other data
US6332031A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 2000 |
| Grant date | Dec 18, 2001 |
| Priority date | — |
| Expiry date | Jul 14, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0061
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Multiple digital watermarks, each of which has different characteristics, are embedded in a document. The characteristics of the various watermarks are chosen so that each of the watermarks will be affected in a different manner if the document is subsequently copied and reproduced. The detection process or mechanism reads each of the watermark and compares their characteristics. While wear and handling may change the characteristics of the digital watermarks in a document, the relationship between the characteristic of multiple digital watermarks in a document will never-the-less give an indication as to whether a document is an original or a copy of an original.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.