Embedding digital watermarks in spot colors
US6993149B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 2001 |
| Grant date | Jan 31, 2006 |
| Priority date | — |
| Expiry date | Sep 20, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2201/0051
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention relates to digitally watermarking spot color images. In one embodiment, an original spot color is replaced with a combination of cyan (C), magenta (M) and yellow (Y) components and the original spot color. The CMY components convey a digital watermark. Preferably, a large percentage halftone process screens the spot color. This screened spot color is combined with the CMY components. Combining the CMY components with a large percentage halftone screening results in a watermarked image color that closely approximates to the original spot color. In another embodiment, a spot color is halftone-screened to a percentage of its original intensity. The screened-back spot color is modulated to accommodate a watermark signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.