This is based on CIE Yu'v' (1976) and is a further attempt to linearise the perceptibility of unit vector colour differences. It is a non-linear colour space, but the conversions are reversible. Colouring information is centered on the colour of the white point of the system, subscript n, (D65 in most TV systems). The non-linear relationship for Y* is intended to mimic the logarithmic response of the eye.
L* = 116((Y/Yn)^(1/3)) - 16 for Y/Yn>0.008856
L* = 903.3(Y/Yn) for Y/Yn<=0.008856
u* = 13L*(u'-u'n)
v* = 13L*(v'-v'n)
\begin{verbatim}
L* scales from 0 to 100 for relative luminance (Y/Yn) scaling 0 to 1.
There are three other, more meaningful polar parameters which more
closely match the human visual experience than do the Cartesian
parameters. Chroma, C*; Hue, huv and Psychometric Saturation, suv.
\begin{verbatim}
C* = (u*^2 + v*^2) ^ 0.5
huv = arctan(v* / u*)
suv = C* / L*
Hue is an angle in four quadrants.