Self validating security documents utilizing watermarks
US6970573B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 2001 |
| Grant date | Nov 29, 2005 |
| Priority date | — |
| Expiry date | Jun 17, 2023 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/3271
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A passport or other document is steganographically encoded with two steganographic digital watermarks. Data conveyed by these watermarks can be cross-checked for expected correspondence to help authenticate the document. The document may also include other machine-readable features, such as a bar code, a magnetic stripe, or OCR-B text. These other machine-readable features can likewise convey data that can be cross-checked for expected correspondence with watermark-conveyed data. In one arrangement, four machine-readable features are provided (two watermarks and two others), three of which convey data relating to a passport identifier, and a different three of which convey data relating to a document batch number. Such logical linking between several machine-readable features allows tampering with any feature to be readily detected. A variety of related methods and apparatuses, some involving a third watermark and biometric data, are also detailed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.