Dither mask creating method and creating device
US7330291B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 1, 2002 |
| Grant date | Feb 12, 2008 |
| Priority date | — |
| Expiry date | Oct 14, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/405
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a computer generation of a dither mask for conversion of a continuous-tone image into a halftone image, a pixel array having a size in accordance with the dither mask is partitioned into blocks. Initial pixel values are determined such that the occurrences of pixel values will be substantially uniform in the blocks. A pair of exchange target pixels are selected at random from the pixels in one of the blocks and function values of a predetermined evaluation function that indicates a characteristic of the pixel value configuration of the pixels in this block are computed for the two cases where pixel values are exchanged among the exchange target pixels and where not exchanged. These function values are compared to judge whether exchange should be performed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.