ipa: ipu3: awb: Correct the gains calculation

The factor used right now in the IPU3 is 8192, as a multiplier of the
estimated gain. This is wrong, as the isp is adding 1.0 to the gain
applied, ie Pout = { Pin * (1 + Gx) }.

Fix it, and to ease the reading, introduce a small helper function.

Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/ipa/ipu3/algorithms/awb.h b/src/ipa/ipu3/algorithms/awb.h
index 9a50a985..0acd2148 100644
--- a/src/ipa/ipu3/algorithms/awb.h
+++ b/src/ipa/ipu3/algorithms/awb.h
@@ -73,6 +73,7 @@ private:
 	void awbGreyWorld();
 	uint32_t estimateCCT(double red, double green, double blue);
 	static constexpr uint16_t threshold(float value);
+	static constexpr uint16_t gainValue(double gain);
 
 	std::vector<RGB> zones_;
 	Accumulator awbStats_[kAwbStatsSizeX * kAwbStatsSizeY];