Single-color screen patterns for copy protection
US8444181B2 · kind B2 · utility
3Cited by
22References
58Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 16, 2007 |
| Grant date | May 21, 2013 |
| Priority date | — |
| Expiry date | Jan 12, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2201/327
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A verifiable/copy-protected document features a combination of nearly identical line-screen patterns for embedding latent images within visually integrated settings. The latent images can be detected for purposes of verification with a matching viewer but are indistinguishable from their visually integrated settings under ordinary viewing conditions. The line-screen patterns, which can be incorporated into document artwork, are printed at certain combinations of line frequencies and print densities so that the line-screen patterns digitally reproduce as a largely undifferentiated solid tint.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.