[libcamera-devel] [PATCH] ipa: rpi: alsc: Do not allow zero colour ratio statistics

[Kieran Bingham]

Quoting Naushir Patuck via libcamera-devel (2023-11-22 09:15:58)
> Hi David,
> 
> Thank you for this fix.
> 
> On Wed, 22 Nov 2023 at 09:13, David Plowman via libcamera-devel
> <libcamera-devel at lists.libcamera.org> wrote:
> >
> > The algorithm computes R/G and B/G colour ratio statistics which we
> > should not allow to go to zero because there is clearly no gain you
> > could apply to R or B to equalise them. Instead flag such regions as
> > having "insufficient data" in the normal manner.
> >
> > Signed-off-by: David Plowman
> 
> Missing your email there :)

Can be fixed while applying...

> 
> Reviewed-by: Naushir Patuck <naush at raspberrypi.com>

Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> 
> > ---
> >  src/ipa/rpi/controller/rpi/alsc.cpp | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/src/ipa/rpi/controller/rpi/alsc.cpp b/src/ipa/rpi/controller/rpi/alsc.cpp
> > index b7413611..8a205c60 100644
> > --- a/src/ipa/rpi/controller/rpi/alsc.cpp
> > +++ b/src/ipa/rpi/controller/rpi/alsc.cpp
> > @@ -548,7 +548,9 @@ static void calculateCrCb(const RgbyRegions &awbRegion, Array2D<double> &cr,
> >         for (unsigned int i = 0; i < cr.size(); i++) {
> >                 auto s = awbRegion.get(i);
> >
> > -               if (s.counted <= minCount || s.val.gSum / s.counted <= minG) {
> > +               /* Do not return unreliable, or zero, colour ratio statistics. */
> > +               if (s.counted <= minCount || s.val.gSum / s.counted <= minG ||
> > +                   s.val.rSum / s.counted <= minG || s.val.bSum / s.counted <= minG) {
> >                         cr[i] = cb[i] = InsufficientData;
> >                         continue;
> >                 }
> > --
> > 2.30.2
> >