COMPUTER COLOR SYSTEMS

Many possible choices for 3 basis functions

XYZ-system
-- from CIE (International Commission on Illumination, 1931) standard:

RGB-system is dominant in computer graphics -- NOTE: eye is most sensitive to green and least to blue. This can be exploited in distribution of bits (e.g., 3:3:2)

YIQ-system is dominant for TV transmission.
-- "Y" is luminance and is most important.

A color in any system is a triple of values (a,b,c)
-- the range of representable colors is the gamut

Transformation between two systems
-- e.g., there is a matrix to convert from YIQ to RGB values

RGBA-System
-- "A" for the "alpha" channel, or transparency.

Color Indexing
-- versus "true color"