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

[Naushir Patuck]

Hi David,

On Wed, 21 Jul 2021 at 12:52, David Plowman <david.plowman at raspberrypi.com>
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>


> ---
>  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'
> --
> 2.20.1
>
>
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