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authorJean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>2021-10-07 17:46:12 +0200
committerJean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>2021-10-22 07:29:53 +0200
commitfac6734a4f1de85a58963d984300f45143508b3a (patch)
tree0b0aff11f23659245ad5474850ca301eb1ea27ce /src/ipa/ipu3
parent9469fededd0981784733c6cc3bb7690e4865bed4 (diff)
ipa: ipu3: awb: Change minimal green threshold value
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>
Diffstat (limited to 'src/ipa/ipu3')
-rw-r--r--src/ipa/ipu3/algorithms/awb.cpp9
1 files changed, 8 insertions, 1 deletions
diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
index c5976c6f..91364a04 100644
--- a/src/ipa/ipu3/algorithms/awb.cpp
+++ b/src/ipa/ipu3/algorithms/awb.cpp
@@ -17,7 +17,14 @@ namespace ipa::ipu3::algorithms {
LOG_DEFINE_CATEGORY(IPU3Awb)
-static constexpr uint32_t kMinGreenLevelInZone = 32;
+/*
+ * When zones are used for the grey world algorithm, they are only considered if
+ * their average green value is at least 16/255 (after black level subtraction)
+ * 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).
+ */
+static constexpr uint32_t kMinGreenLevelInZone = 16;
/*
* Minimum proportion of non-saturated cells in a zone for the zone to be used