When zones are used for the grey world algorithm, they are only
considered if their average green value is at least 32/255 to exclude
zones that are too dark and don't provide relevant colour information
(on the opposite side of the spectrum, saturated regions are excluded by
the ImgU statistics engine).
The algorithm requires a minimal number of zones that meet this criteria
in order to run. Now that we correct the black level, the 32/255 minimal
value is a bit high and prevents the algorithm for running in low-light
conditions. Lower the value to 16/255 to fix it.
Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Acked-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Jean-Michel Hautbois
fac6734a4f