ipa: raspberrypi: Estimate the colour temerature if starting with fixed colour gains

When the AWB is started from "cold" with fixed colour gains, we try to
estimate the colour temperature this corresponds to (if a calibrated
CT curve was supplied). When fixed colour gains are set after the AWB
has been running, we leave the CT estimate alone, as the one we have
is probably sensible.

This estimated colour is passed out in the metadata for other
algorithms - notably ALSC - to use.

Signed-off-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/src/ipa/raspberrypi/controller/rpi/alsc.cpp b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
index 183a0c95..c354c985 100644
--- a/src/ipa/raspberrypi/controller/rpi/alsc.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/alsc.cpp
@@ -146,6 +146,7 @@ void Alsc::Read(boost::property_tree::ptree const &params)
 	config_.threshold = params.get<double>("threshold", 1e-3);
 }
 
+static double get_ct(Metadata *metadata, double default_ct);
 static void get_cal_table(double ct,
 			  std::vector<AlscCalibration> const &calibrations,
 			  double cal_table[XY]);
@@ -210,6 +211,9 @@ void Alsc::SwitchMode(CameraMode const &camera_mode,
 	// change.
 	bool reset_tables = first_time_ || compare_modes(camera_mode_, camera_mode);
 
+	// Believe the colour temperature from the AWB, if there is one.
+	ct_ = get_ct(metadata, ct_);
+
 	// Ensure the other thread isn't running while we do this.
 	waitForAysncThread();
 
@@ -254,7 +258,7 @@ void Alsc::fetchAsyncResults()
 	memcpy(sync_results_, async_results_, sizeof(sync_results_));
 }
 
-static double get_ct(Metadata *metadata, double default_ct)
+double get_ct(Metadata *metadata, double default_ct)
 {
 	AwbStatus awb_status;
 	awb_status.temperature_K = default_ct; // in case nothing found