[PD] get average luminance of the camera

[enrike]

hi

Is it possible to get the average luminance of the camera input using GEM?

I am exploring pix_data but as far as I can see it only works with 
individual pixels. If I could average or reduce the color information 
from the camera to a single color, then I think I could just take the 
pix_data grey value of any pixel. But I am not sure this can be done. I 
am checking different pix_ objects but I dont see how I could get this 
to work. Any tips?


thanks

enrike