Robust watermark method and apparatus for digital signals
US6345100B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 14, 1998 |
| Grant date | Feb 5, 2002 |
| Priority date | — |
| Expiry date | Oct 14, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0065
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Watermark data is encoded in a digitized signal by forming a noise threshold spectrum which represents a maximum amount of imperceptible noise, spread-spectrum chipping the noise threshold spectrum with a relatively endless stream of pseudo-random bits to form a basis signal, dividing the basis signal into segments, and filtering the segments to smooth segment boundaries. The data encoded in the watermark signal is precoded to make the watermark data inversion robust and is convolutional encoded to further increase the likelihood that the watermark data will subsequently be retrievable notwithstanding lossy processing of the watermarked signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.