US 5,673,065 A · Color reduction and conversion using an ordinal lookup table

Abstract

A color image signal is reduced and converted. Dithering the remainder is an embodiment. For example a pixel value is separated into its pixel components. Each component is further split into most-significant bit (MSB) and least-significant bit (LSB) parts. The MSBs from each component are combined to provide a color number. The color number is an index to a nearest-color map. Each entry in the nearest-color map is an index to a spectrum color palette having color entries. The spectrum color palette is an evenly divided spectrum of the colors displayable on an associated video display system. The particular color accessed in the color spectrum palette by the color palette is used for the pixel in the image being reduced and converted. In an embodiment, the LSBs of each color component are dithered. If the value of the LSBs of a color component are greater than a dither threshold value, a one is added to the MSBs of the color, prior to the MSB values being combined into the color number.

Claims42

Dependent claims

A computer-implemented method for converting a color image composed of color pixels, comprising the steps of:

(a) receiving components of a color pixel of the color image;
(b) truncating most-significant bits from each component of the color pixel;
(c) combining the most-significant truncated bits to form a color number, the color number representing an index to a nearest-color map;
(d) generating an index to a color palette using the nearest-color map index, the color palette containing a plurality of colors;
and
(e) accessing one of the plurality of colors to represent the color pixel using the color palette index.

3 more elements

Dependencies are inferred from the claim text.

Color reduction and conversion using an ordinal lookup table

Life of this patent

Color reduction and conversion using an ordinal lookup table

Life of this patent

Abstract

Claims42