[libcamera-devel] [PATCH 2/3] utils: raspberrypi: ctt: Fix usage of findHomography function

[Laurent Pinchart]

Hello,

On Wed, Jul 21, 2021 at 02:10:02PM +0100, Naushir Patuck wrote:
> On Wed, 21 Jul 2021 at 12:52, David Plowman wrote:
> 
> > The OpenCV findHomography function now raises an unhandled error if it
> > receives fewer than 4 points whereas previously the limit was 3. This
> > makes no material difference to the behaviour of the tuning tool as it
> > will continue to search for the Macbeth chart at different scales.
> >
> > Signed-off-by: David Plowman <david.plowman at raspberrypi.com>
> 
> I wonder if we could perhaps do a OpenCV version check on startup to
> catch things like this in the future?  But that's not related to this fix...
> 
> Reviewed-by: Naushir Patuck <naush at raspberrypi.com>

Given that this change remains backward-compatible with older OpenCV
version, it doesn't depend on a new minimum version, so

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> > ---
> >  utils/raspberrypi/ctt/ctt_macbeth_locator.py | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> > b/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> > index 35c84807..cae1d334 100644
> > --- a/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> > +++ b/utils/raspberrypi/ctt/ctt_macbeth_locator.py
> > @@ -597,10 +597,10 @@ def get_macbeth_chart(img, ref_data):
> >                      ref_cents.append(ref_cent)
> >
> >                      """
> > -                    At least three squares need to have voted for a centre in
> > +                    At least four squares need to have voted for a centre in
> >                      order for a transform to be found
> >                      """
> > -            if len(sq_cents) < 3:
> > +            if len(sq_cents) < 4:
> >                  raise MacbethError(
> >                      '\nWARNING: No macbeth chart found!'
> >                      '\nNot enough squares found'

-- 
Regards,

Laurent Pinchart