Hiding digital data in a digital audio or video carrier signal
US6768709B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 23, 2001 |
| Grant date | Jul 27, 2004 |
| Priority date | — |
| Expiry date | Nov 16, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B23/284
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc in which hidden data are stored for forensic tracking or copy protection purposes. This disc includes a contiguous user data portion comprising a set of user data samples which, when accessed by a readback system, generates a human detectable output. The disc further includes a null zone adjacent the contiguous user data portion comprising a sequence of user data fields storing a set of user data samples which, when accessed by a readback system, generates an output with a specified signal to noise ratio so as to be substantially undetectable by a human, wherein hidden data are written to at least selected ones of the user data fields of the null zone to convey a specified informational message related to the optical disc, the specified informational message undetectable by a human when the null zone is accessed by the readback system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.