diff options
| author | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2022-09-04 04:21:18 +0300 |
|---|---|---|
| committer | Laurent Pinchart <laurent.pinchart@ideasonboard.com> | 2022-09-28 05:41:15 +0300 |
| commit | 2f1efe50a938b83a6b4b236406b74c20ead29beb (patch) | |
| tree | 591a55213ff55f5e95324eef950672150d60ea4a /src | |
| parent | 9b389ce79eb143a82e998bfe5b09470272a25600 (diff) | |
ipa: rkisp1: awb: Remove bias from gain calculation
The red and blue gains are computed by dividing the green mean by the
red and blue means respectively. An offset of 1 is added to the dividers
to avoid divisions by zero. This introduces a bias in the gain values.
Fix it by clamping the divisors to a minimum of 1.0 instead of adding an
offset.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/ipa/rkisp1/algorithms/awb.cpp | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp index eb32cd72..3349948a 100644 --- a/src/ipa/rkisp1/algorithms/awb.cpp +++ b/src/ipa/rkisp1/algorithms/awb.cpp @@ -280,10 +280,11 @@ void Awb::process(IPAContext &context, /* * Estimate the red and blue gains to apply in a grey world. The green - * gain is hardcoded to 1.0. + * gain is hardcoded to 1.0. Avoid divisions by zero by clamping the + * divisor to a minimum value of 1.0. */ - double redGain = greenMean / (redMean + 1); - double blueGain = greenMean / (blueMean + 1); + double redGain = greenMean / std::max(redMean, 1.0); + double blueGain = greenMean / std::max(blueMean, 1.0); /* * Clamp the gain values to the hardware, which expresses gains as Q2.8 |