Converting a color image into a luminance image may be accomplished by
putting the weights for R, G, and B along the top row of the matrix:
The recommended weight values for 
, 
, and 
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.[18]