Juxtaposed clustered dispersed dot halftoning
US11968345B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2023 |
| Grant date | Apr 23, 2024 |
| Priority date | — |
| Expiry date | Jan 11, 2043 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6086
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
We disclose a method for printing by rotogravure, flexography, offset, inkjet or electrophotography invisible images that are viewable under UV light. The method generates juxtaposed dispersed dot halftones by first creating juxtaposed clustered dot halftones and by applying to them dispersed dot halftoning according to a blackness reduction factor. Dispersed dot halftoning is embodied by random threshold error diffusion. The resulting dispersed dot halftones comprise pixel segments located within the areas defined by the clustered dots. These pixel segments specify the areas of the cells to be engraved onto the rotogravure cylinder. For offset, they can be imaged onto an offset plate or for electrophotography, onto a photoconductor. The disclosed juxtaposed dispersed dot halftoning method can be embedded into a framework for the reproduction of fluorescent full color images with three or more invisible fluorescent inks. These invisible fluorescent color images offer a strong protection against counterfeits.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.