Alternatively, color is represented using digital values B, C (chroma) and H (hue), where cos C=D/B...http://www.google.com/patents/US8116562?utm_source=gb-gplus-sharePatent US8116562 - Image processing including, but not limited to, logarithimic coding in color coordinate systems including systems with a coordinate defined by a square root of a quadratic polynomial in tristimulus values and, poss