Method and apparatus for forming multi-level dither images from an input digital image
US6757079B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 13, 2000 |
| Grant date | Jun 29, 2004 |
| Priority date | — |
| Expiry date | Mar 13, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/40087
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for forming multi-level dither images from an input digital image are disclosed. The difference between a pixel value of the input digital image and a pixel value of a dither image corresponding to the input digital image is first determined. Next, the difference is processed by an error filter to correct the pixel value of the input digital image to generate a corrected image pixel value. The corrected image pixel value is then compared to at least two threshold values, each corresponding to a pixel value of the dither image, to determine a threshold value that is nearest to the corrected image pixel value, thereby obtaining a pixel value of the dither image corresponding to said threshold value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.