ipa: rkisp1: awb: Avoid division by zero

As the gains can also be specified manually, the regulation can run into
numeric instabilities by dividing by near zero. Mitigate that by
applying a small minium value.

Signed-off-by: Stefan Klug <stefan.klug@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
index bd8430ad..399fb51b 100644
--- a/src/ipa/rkisp1/algorithms/awb.cpp
+++ b/src/ipa/rkisp1/algorithms/awb.cpp
@@ -413,9 +413,9 @@ RGB<double> Awb::calculateRgbMeans(const IPAFrameContext &frameContext, const rk
 	/*
 	 * The ISP computes the AWB means after applying the colour gains,
 	 * divide by the gains that were used to get the raw means from the
-	 * sensor.
+	 * sensor. Apply a minimum value to avoid divisions by near-zero.
 	 */
-	rgbMeans /= frameContext.awb.gains;
+	rgbMeans /= frameContext.awb.gains.max(0.01);
 
 	return rgbMeans;
 }