Method and apparatus for creating a dither pattern
US4823189A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1987 |
| Grant date | Apr 18, 1989 |
| Priority date | — |
| Expiry date | May 8, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/52
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A record in which a color is represented on a record medium at a selected gray scale level is created by resolving an addressable area of the record medium into a square array of addressable record locations and organizing the record locations into a plurality of groups each containing a 4.times.4 array of record locations. The groups are organized into a plurality of dither cells each containing a 4.times.4 array of groups, whereby each dither cell contains 256 addressable record locations. An [i+(j.times.16)]th gray scale level is established within a selected area of the record medium, where i is an integer in the range from zero to 16, j is an integer in the range from zero to 16 and [i+(j.times.16)] is an integer in the range from zero to 255, by addressing j record locations in each group of each dither cell within the selected area and addressing one additional record location in each of the i groups of each dither cell within the selected area, the j addressed locations in each group being substantially contiguous and being in substantially the same positions in their group as the j addressed locations in each other group, and the i groups which contain an additional addres…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.