Color coordinate systems including systems with a coordinate defined by a square root of a quadratic polynomial in tristimulus values and, possibly, by a sign of a function of one or more of tristimulus values

摘要

Color is represented using digital values B (brightness), e and f such that B=√{square root over (D²+E²+F²)}, e=E/B, f=F/B, where DEF is a linear color coordinate system. Alternatively, color is represented using digital values B, C (chroma) and H (hue), where cos C=D/B and tan H=E/F. Brightness can be changed without a color shift by changing the B coordinate and leaving unchanged the other coordinates e and f or C and H. Other features are also provided.