Color indication comparison method
US4770534A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 1986 |
| Grant date | Sep 13, 1988 |
| Priority date | — |
| Expiry date | Mar 24, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J2003/466
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of determining the color difference between two similar colors including the steps of determining the tristimulus values for a reference color with which another color is to be compared, providing a planar chromaticity diagram for the values other than brightness in which the values for the reference colors are at the origin and the abscissa and ordinates of the diagram, determining the hue of the reference color and plotting in said diagram an equi-hue line, determining the tristimulus values for the other color to be compared to the reference color and plotting the values other than brightness on the diagram, plotting an equi-saturation line on the diagram perpendicular to the equi-hue line and extending through the origin, plotting lines parallel to the equi-hue and equi-saturation lines through the position of the plotted values for the other color and extending across the equi-hue and equi-saturation lines, so that the difference in the tristimulus values for the other color from the reference color are shown by measurements along said parallel lines. In addition, a brightness line is provided having the brightness value of the reference color at the center of the lin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.