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

[David Plowman]

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>
---
 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