Converting a color image into a luminance image may be accomplished by
scaling each component by its weight in the luminance equation.
![\begin{displaymath}
\left[
\begin{array}{c}
L \\
L \\
L \\
0
\end{array}\righ...
...left[
\begin{array}{c}
R \\
G \\
B \\
A
\end{array}\right]
\end{displaymath}](img345.gif)
, 
, and 
are
, 
, and 
. Some authors have used the values
from the YIQ color conversion equation (
, 
, and
), but Haeberli notes that these values are incorrect in a
linear RGB color space.[42]