Halftoning using dot and line screens to avoid two and three color moiré
US6985256B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 2001 |
| Grant date | Jan 10, 2006 |
| Priority date | — |
| Expiry date | Jun 18, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Moiré free color halftoning is achieved through the use of two dot screens and one or two line screens. The line screens may be, for example hybrid line screens. Frequency vectors associated with the screens combine to produce moiré frequency vectors representing moiré frequencies above or below the visual range. In one embodiment lines screens are used to halftone yellow and black separations and dot screens are used to halftone cyan and magenta separations. The dot screens are oriented at 15 and 75 degrees. The line screens are oriented at 45 and 135 degrees. Selected screens and screen orientations minimize screen interaction with mechanical or optical artifacts of a rendering device, thereby minimizing mechanical and optical moiré.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.