User:Pete k 1948/Sandbox

TSL is a color space that is based on Tint, Saturation, and Luminance.

The transformation from RGB to TSL is:

$S={\sqrt {{\frac {9}{5}}\left(r'^{2}+g'^{2}\right)}}$

$T={\begin{cases}{\frac {1}{2\pi }}\arctan {\frac {r'}{g'}}+{\frac {1}{4}},&{\mbox{if}}~g'\neq 0\land {\frac {r'}{g'}}>0\\{\frac {1}{2\pi }}\arctan {\frac {r'}{g'}}+{\frac {3}{4}},&{\mbox{if}}~g'\neq 0\land {\frac {r'}{g'}}<0\\{\frac {1}{2}},&{\mbox{if}}~g'=0\\\end{cases}}$

$L=0.299R+0.587G+0.114B$

where:

$r'=r-{\tfrac {1}{3}}$

$g'=g-{\tfrac {1}{3}}$

$r={\tfrac {R}{R+G+B}}$

$g={\tfrac {G}{R+G+B}}$

An earlier version of the formula for T used the sign of $g'$ to determine whether to add ${\tfrac {1}{4}}$ or ${\tfrac {3}{4}}$ to ${\tfrac {1}{2\pi }}$ arctan ${\tfrac {r'}{g'}}$. That formula generates a discontinuity in the calculated T values for $g'$ near zero; using the sign of ${\tfrac {r'}{g'}}$ gives a continuous value of ${\tfrac {1}{2}}$ for for $g'$ near zero.

References

{{color-stub}}

Category:Color space