Bi-level digital color printer system exhibiting improved undercolor removal and error diffusion procedures
US5402245A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1994 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Jan 27, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6022
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system selectively enables a printer to deposit on a sheet C, M, Y and K color dots at each of the plurality of pixel locations to produce a color image. The system comprises a memory for storing C, M, Y and K color values for each pixel in the color image and a processor for controlling selective deposition of the C, M, Y and K colors. The processor determines a gray value for each pixel location from values stored in the C, M, and Y color planes. The processor subtracts the determined gray value from the C, M, and Y values which correspond to the pixel location and then determines a relationship of the gray value to a non-linear function and in dependence upon the relationship alters the C, M and Y pixel values accordingly. The processor either (1) adds the gray value back to the C, M, and Y values for the pixel location, or (2) adds a first portion of the gray value to the C, M, and Y values for the pixel location and a second portion of the gray value to the K value for the pixel location; or (3) adds all of the gray value to a K value for the pixel location. As a result, the C, M, Y and K values are altered in accordance with the determined gray value. The altered color valu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.