Synthesis of authenticable luminescent color halftone images
US8355169B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 23, 2010 |
| Grant date | Jan 15, 2013 |
| Priority date | — |
| Expiry date | Sep 30, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/1205
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention enables creating authenticable multi-ink luminescent continuous tone color halftone images offering means of verifying their authenticity. The invented luminescent color halftone image synthesizing techniques enable increasing the attractiveness and aesthetics of color images. The invention relies on daylight luminescent inks, color prediction models for daylight luminescent halftones, color gamuts of luminescent and non-luminescent inks, color separation into luminescent and non-luminescent ink layers, mapping of input gamuts into a luminescent target gamuts by gamut reduction and/or expansion strategies, and luminescent color halftone image generation. The basic authentication is performed by examining the excitation trace image of the synthesized luminescent color halftone image under an illuminant active within its excitation wavelength range. Further authentication means include hiding messages under one or several different illuminants as well as hiding message with different sets of luminescent inks. Hidden messages are recovered under illuminants different from their reference illuminant.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.