Luminance emphasized color image rendering
US5341464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 16, 1993 |
| Grant date | Aug 23, 1994 |
| Priority date | — |
| Expiry date | Jun 16, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T11/001
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A high color resolution image is rendered using a palette having a lower color resolution. The color of each pixel in the image is mapped to the nearest of the palette colors located on or between levels of uniform luminance adjacent to the pixel color. The mapping of the pixel color is further constrained to exclude palette colors for which double the error to the pixel color is outside the color gamut. The mapping is performed efficiently by a look-up table, the size of which is reduced by first dithering the pixel color to a color in an intermediate palette and then indexing the table using the intermediate palette color to find the reduced palette color. The mapping can be performed in an error diffusion process in which the pixel's color is modified by error diffused from any previously rendered neighboring pixels, then mapped to a reduced palette color to render the pixel with the reduced palette color, and finally diffuse any error between the pixel's color and the reduced palette color to any not yet rendered pixels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.