[libcamera-devel] [PATCH v2 3/6] src: ipa: raspberrypi: agc: Add GetConvergenceFrames method to AWB base class

[Laurent Pinchart]

Hi David,

Thank you for the patch.

On Mon, Dec 07, 2020 at 06:01:18PM +0000, David Plowman wrote:
> 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 at raspberrypi.com>

Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>

> ---
>  src/ipa/raspberrypi/controller/awb_algorithm.hpp |  1 +
>  src/ipa/raspberrypi/controller/rpi/awb.cpp       | 13 +++++++++++++
>  src/ipa/raspberrypi/controller/rpi/awb.hpp       |  2 ++
>  3 files changed, 16 insertions(+)
> 
> diff --git a/src/ipa/raspberrypi/controller/awb_algorithm.hpp b/src/ipa/raspberrypi/controller/awb_algorithm.hpp
> index 5be0c9f4..84ae313b 100644
> --- a/src/ipa/raspberrypi/controller/awb_algorithm.hpp
> +++ b/src/ipa/raspberrypi/controller/awb_algorithm.hpp
> @@ -15,6 +15,7 @@ class AwbAlgorithm : public Algorithm
>  public:
>  	AwbAlgorithm(Controller *controller) : Algorithm(controller) {}
>  	// An AWB algorithm must provide the following:
> +	virtual unsigned int GetConvergenceFrames(unsigned int mistrust_frames) const = 0;
>  	virtual void SetMode(std::string const &mode_name) = 0;
>  	virtual void SetManualGains(double manual_r, double manual_b) = 0;
>  };
> diff --git a/src/ipa/raspberrypi/controller/rpi/awb.cpp b/src/ipa/raspberrypi/controller/rpi/awb.cpp
> index 020825e3..6b359ac5 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 +166,18 @@ void Awb::Initialise()
>  	prev_sync_results_ = sync_results_;
>  }
>  
> +unsigned int Awb::GetConvergenceFrames(unsigned int mistrust_frames) const
> +{
> +	// If colour gains have been explicitly set, there is no convergence
> +	// to happen, so no need to drop any frames - return zero.
> +	// Otherwise, any frames for which we have been told not to trust the
> +	// statistics must be added to our own count.
> +	if (manual_r_ && manual_b_)
> +		return 0;
> +	else
> +		return config_.convergence_frames + mistrust_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..d86b9598 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(unsigned int mistrust_frames) 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;

-- 
Regards,

Laurent Pinchart