Color image processing apparatus for color matching and color matching processing method
US5764795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1996 |
| Grant date | Jun 9, 1998 |
| Priority date | — |
| Expiry date | Jan 24, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6022
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Three-dimensional LUTs produce a lightness signal L* from input color signals C, M and Y. The three-dimensional LUTs are respectively provided for four divisional sections of an input color signal K. A three-dimensional LUT switching device judges to what section a current value of the input color signal K belongs. A selector selects one of the LUTs in accordance with a judgment result. Similar processing is performed for chromaticity signals a* and b*. According to another aspect of the invention, three-dimensional LUT color converters produce color signals L.sub.2 *, a.sub.2 * and b.sub.2 * based on only input color signals C, M and Y. A position in the L*a*b* space of the color signals L.sub.2 *, a.sub.2 * and b.sub.2 * has a deviation from a position of color signals L.sub.1 *, a.sub.1 * and b.sub.1 * to be output actually. Based on an input color signal K, a one-dimensional LUT produces a lightness signal L.sub.3 *, which corresponds to the deviation. A color signal combining means produces final output color signals L.sub.1 *, a.sub.1 * and b.sub.1 * based on the color signals L.sub.2 *, a.sub.2 * and b.sub.2 * and the lightness signal L.sub.3 *.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.