ipa: raspberrypi: awb: Add GetConvergenceFrames method to AWB base class

We add a GetConvergenceFrames method to the AwbAlgorithm class which
can be called when the AWB is started from scratch. It suggests how
many frames should be dropped before displaying any (while the AWB
converges).

The Raspberry Pi specific implementation makes this customisable from
the tuning file.

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>

2 files changed, 13 insertions, 0 deletions

diff --git a/src/ipa/raspberrypi/controller/rpi/awb.cpp b/src/ipa/raspberrypi/controller/rpi/awb.cpp
index 020825e3..10600f75 100644
--- a/src/ipa/raspberrypi/controller/rpi/awb.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/awb.cpp
@@ -59,6 +59,7 @@ void AwbConfig::Read(boost::property_tree::ptree const &params)
 	bayes = params.get<int>("bayes", 1);
 	frame_period = params.get<uint16_t>("frame_period", 10);
 	startup_frames = params.get<uint16_t>("startup_frames", 10);
+	convergence_frames = params.get<unsigned int>("convergence_frames", 3);
 	speed = params.get<double>("speed", 0.05);
 	if (params.get_child_optional("ct_curve"))
 		read_ct_curve(ct_r, ct_b, params.get_child("ct_curve"));
@@ -165,6 +166,16 @@ void Awb::Initialise()
 	prev_sync_results_ = sync_results_;
 }
 
+unsigned int Awb::GetConvergenceFrames() const
+{
+	// If colour gains have been explicitly set, there is no convergence
+	// to happen, so no need to drop any frames - return zero.
+	if (manual_r_ && manual_b_)
+		return 0;
+	else
+		return config_.convergence_frames;
+}
+
 void Awb::SetMode(std::string const &mode_name)
 {
 	std::unique_lock<std::mutex> lock(settings_mutex_);
diff --git a/src/ipa/raspberrypi/controller/rpi/awb.hpp b/src/ipa/raspberrypi/controller/rpi/awb.hpp
index 545d85a8..6fc045ce 100644
--- a/src/ipa/raspberrypi/controller/rpi/awb.hpp
+++ b/src/ipa/raspberrypi/controller/rpi/awb.hpp
@@ -37,6 +37,7 @@ struct AwbConfig {
 	uint16_t frame_period;
 	// number of initial frames for which speed taken as 1.0 (maximum)
 	uint16_t startup_frames;
+	unsigned int convergence_frames; // approx number of frames to converge
 	double speed; // IIR filter speed applied to algorithm results
 	bool fast; // "fast" mode uses a 16x16 rather than 32x32 grid
 	Pwl ct_r; // function maps CT to r (= R/G)
@@ -82,6 +83,7 @@ public:
 	char const *Name() const override;
 	void Initialise() override;
 	void Read(boost::property_tree::ptree const &params) override;
+	unsigned int GetConvergenceFrames() const override;
 	void SetMode(std::string const &name) override;
 	void SetManualGains(double manual_r, double manual_b) override;
 	void SwitchMode(CameraMode const &camera_mode, Metadata *metadata) override;