Image processing method and apparatus
US6552822B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 23, 1999 |
| Grant date | Apr 22, 2003 |
| Priority date | — |
| Expiry date | Feb 23, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/2059
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multiple-level error diffusion processing is performed to obtain an image of a high quality with uniform texture and reduced roughness, while reducing a gradation level. An image processing apparatus comprises a first error diffusion processing section for selectively performing error diffusion processing on input image data according to its gradation values and a second error diffusion processing section for performing error diffusion processing of three or more quantization levels on the output data of the first error diffusion processing section for outputting as output image data. A selective quantization section of the first error diffusion processing section performs such a quantization that errors are supplemented selectively centering a portion where no error is produced through quantization in a quantization section of the second error diffusion processing section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.