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13.2.4.3 Conversion to Luminance
Converting a color image into a luminance image may be accomplished by
scaling each component by its weight in the luminance equation.
The recommended weight values for Rw, Gw, and Bw are
0.3086, 0.6094, and 0.0820. Some authors have used the values
from the YIQ color conversion equation (0.299, 0.587, and
0.114), but Haeberli notes that these values are incorrect in a
linear RGB color space.[39]
David Blythe
1999-08-06
![\begin{displaymath}\left[
\begin{array}{c}
L \\
L \\
L \\
0
\end{array}\right...
...left[
\begin{array}{c}
R \\
G \\
B \\
A
\end{array}\right]
\end{displaymath}](img209.gif)