Method and apparatus for color halftoning using different halftoning techniques for halftoning different dot planes
US5930010A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1996 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Jan 31, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Digital halftoning is used to reduce the number of pixel levels used to represent a multiple dot plane image to a smaller number of pixel levels for display on an output device such as an ink-jet printer. Two algorithms commonly used to halftone the dots of a given dot plane are error diffusion and ordered dither. Error diffusion produces patterns of dots that are pleasing to the human visual system but is computationally complex. Ordered dither operates quickly but produces patterns of dots that are visually objectionable. A method is taught in the present invention that employs error diffusion to halftone dot planes that contain relatively dark dots that are visually apparent, and employs ordered dither to halftone dot planes that contain relatively light dots that are not noticeable. The resulting output is pleasing to the human visual system and computed quickly.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.