Digital halftoning combining multiple screens within a single image
US6118935A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 1997 |
| Grant date | Sep 12, 2000 |
| Priority date | — |
| Expiry date | Apr 1, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/405
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method of producing enhanced digital imaging for printing data, in flexographic and other types of printing environments, combines halftone screens which represent continuous "gray tone" (grey tone) levels, wherein the transition from one screen to the other is not visually detectable by an observer of the reproduction results. The digital processing method includes combining an (FM generated) dispersed dot screen with an (AM generated) cluster dot screen, with an overlay interval of both screens of acceptable resultant dot size (percent coverage), to obtain enhanced overall definition over the grey scale range of 1 to 100 percent (i.e., where 100 is equal to "255" in 8-bit environment), specifically over the more visually perceptive gray scale range of 1 to 20 (i.e., out of 0-255 value). The apparatus which implements the method algorithm is positioned intermediate a desktop publishing system and an image setter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.