Gamut mapping algorithm using inverted gamma function
US6342951B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1998 |
| Grant date | Jan 29, 2002 |
| Priority date | — |
| Expiry date | Dec 16, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/6058
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A new and improved method for mapping out-of-gamut colors into an output gamut in a manner which results in an output image created by an image output terminal which is aesthetically pleasing and faithful to the original input image. A plurality of input pixel color values IPV comprising an input gamut IG are respectively mapped to a corresponding plurality of output pixel color values OPV so that the dynamic lightness range of the input gamut IG is compressed to that of the output gamut OG. This is accomplished by inverting at least one of the gray values defining the input pixel value IPV, applying a gamma function thereto, and then reversing the inversion step. The value of gamma &ggr; controls the amount of lightness compression and is selected based upon either the darkest actual or the darkest expected color in the input gamut IG as compared to the darkest color in the output gamut OG. If necessary, a subsequent gamut clipping operation is performed to map all resulting out-of-gamut output pixel values XOPV to values in the output gamut OG as a second processing step. Preferably, a centroid gamut clipping operation is used to map each out-of-gamut value XOPV to the surface SO…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.