Pixel color modification using look-up tables in image reproduction system
US4727425A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 4, 1986 |
| Grant date | Feb 23, 1988 |
| Priority date | — |
| Expiry date | Jun 4, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/62
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Digital signals are generated for each pixel of an image to be reproduced, corresponding to the values of color components in each pixel. The respective color component values of each pixel are applied to a set of look-up tables (30) so loaded that they recognize whether the color component values of a pixel fall within a color range(s) for which a processing operation is to be carried out. The look-up tables provide an output signal representing one of a number of possible processing operations for that pixel, in the form of an operation number. The operation number signal is applied through a processor (32) to an operation select table (36) which converts the operation number into a specific processing operation for each color component. The processing operations may be retouching, image retention (no change), replacement by a tint value, or dropout. They are carried out by components (44, 42, 38 and 40) under the control of the operation select table, and the resulting pixel values are transferred to an output buffer (24). The look-up tables may define the color ranges within which processing operations are required in terms of a range of a single color component or coinciding r…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.