[PATCH v2 12/17] libipa: awb: Make result of gainsFromColourTemp optional

[Laurent Pinchart]

Hi Stefan,

Thank you for the patch.

On Wed, Mar 19, 2025 at 05:11:17PM +0100, Stefan Klug wrote:
> In the grey world AWB case, if no colour gains are contained in the
> tuning file, the color gains get reset to 1 when the colour temperature
> is set manually. This is unexpected and undesirable. Allow the
> gainsFromColourTemp() function to return a std::nullopt to handle that
> case.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> 
> ---
> 
> Changes in v2:
> - Added this patch
> ---
>  src/ipa/libipa/awb.cpp            |  2 +-
>  src/ipa/libipa/awb.h              |  2 +-
>  src/ipa/libipa/awb_bayes.cpp      |  4 ++--
>  src/ipa/libipa/awb_bayes.h        |  2 +-
>  src/ipa/libipa/awb_grey.cpp       |  6 +++---
>  src/ipa/libipa/awb_grey.h         |  2 +-
>  src/ipa/rkisp1/algorithms/awb.cpp | 16 +++++++++++-----
>  7 files changed, 20 insertions(+), 14 deletions(-)
> 
> diff --git a/src/ipa/libipa/awb.cpp b/src/ipa/libipa/awb.cpp
> index 925fac232709..214bac8b56a6 100644
> --- a/src/ipa/libipa/awb.cpp
> +++ b/src/ipa/libipa/awb.cpp
> @@ -114,7 +114,7 @@ namespace ipa {
>   * does not take any statistics into account. It is used to compute the colour
>   * gains when the user manually specifies a colour temperature.
>   *
> - * \return The colour gains
> + * \return The colour gains or std::nullopt if the conversion is not possible
>   */
>  
>  /**
> diff --git a/src/ipa/libipa/awb.h b/src/ipa/libipa/awb.h
> index 4bab7a451ce5..789a1d534f9a 100644
> --- a/src/ipa/libipa/awb.h
> +++ b/src/ipa/libipa/awb.h
> @@ -39,7 +39,7 @@ public:
>  
>  	virtual int init(const YamlObject &tuningData) = 0;
>  	virtual AwbResult calculateAwb(const AwbStats &stats, unsigned int lux) = 0;
> -	virtual RGB<double> gainsFromColourTemperature(double colourTemperature) = 0;
> +	virtual std::optional<RGB<double>> gainsFromColourTemperature(double colourTemperature) = 0;

You need to include <optional>

>  
>  	const ControlInfoMap::Map &controls() const
>  	{
> diff --git a/src/ipa/libipa/awb_bayes.cpp b/src/ipa/libipa/awb_bayes.cpp
> index d1d0eaf0e68f..d2bcbd83d7f8 100644
> --- a/src/ipa/libipa/awb_bayes.cpp
> +++ b/src/ipa/libipa/awb_bayes.cpp
> @@ -270,7 +270,7 @@ void AwbBayes::handleControls(const ControlList &controls)
>  	}
>  }
>  
> -RGB<double> AwbBayes::gainsFromColourTemperature(double colourTemperature)
> +std::optional<RGB<double>> AwbBayes::gainsFromColourTemperature(double colourTemperature)
>  {
>  	/*
>  	 * \todo In the RaspberryPi code, the ct curve was interpolated in
> @@ -278,7 +278,7 @@ RGB<double> AwbBayes::gainsFromColourTemperature(double colourTemperature)
>  	 * intuitive, as the gains are in linear space. But I can't prove it.
>  	 */
>  	const auto &gains = colourGainCurve_.getInterpolated(colourTemperature);
> -	return { { gains[0], 1.0, gains[1] } };
> +	return RGB<double>{ { gains[0], 1.0, gains[1] } };
>  }
>  
>  AwbResult AwbBayes::calculateAwb(const AwbStats &stats, unsigned int lux)
> diff --git a/src/ipa/libipa/awb_bayes.h b/src/ipa/libipa/awb_bayes.h
> index bb933038d6d2..47ef3cce4d58 100644
> --- a/src/ipa/libipa/awb_bayes.h
> +++ b/src/ipa/libipa/awb_bayes.h
> @@ -27,7 +27,7 @@ public:
>  
>  	int init(const YamlObject &tuningData) override;
>  	AwbResult calculateAwb(const AwbStats &stats, unsigned int lux) override;
> -	RGB<double> gainsFromColourTemperature(double temperatureK) override;
> +	std::optional<RGB<double>> gainsFromColourTemperature(double temperatureK) override;
>  	void handleControls(const ControlList &controls) override;
>  
>  private:
> diff --git a/src/ipa/libipa/awb_grey.cpp b/src/ipa/libipa/awb_grey.cpp
> index d3d2132b8869..d252edb2b6c6 100644
> --- a/src/ipa/libipa/awb_grey.cpp
> +++ b/src/ipa/libipa/awb_grey.cpp
> @@ -98,15 +98,15 @@ AwbResult AwbGrey::calculateAwb(const AwbStats &stats, [[maybe_unused]] unsigned
>   * \return The colour gains if a colour temperature curve is available,
>   * [1, 1, 1] otherwise.
>   */
> -RGB<double> AwbGrey::gainsFromColourTemperature(double colourTemperature)
> +std::optional<RGB<double>> AwbGrey::gainsFromColourTemperature(double colourTemperature)
>  {
>  	if (!colourGainCurve_) {
>  		LOG(Awb, Error) << "No gains defined";
> -		return RGB<double>({ 1.0, 1.0, 1.0 });
> +		return std::nullopt;
>  	}
>  
>  	auto gains = colourGainCurve_->getInterpolated(colourTemperature);
> -	return { { gains[0], 1.0, gains[1] } };
> +	return RGB<double>{ { gains[0], 1.0, gains[1] } };
>  }
>  
>  } /* namespace ipa */
> diff --git a/src/ipa/libipa/awb_grey.h b/src/ipa/libipa/awb_grey.h
> index 7ec7bfa5da9a..f82a368d11cc 100644
> --- a/src/ipa/libipa/awb_grey.h
> +++ b/src/ipa/libipa/awb_grey.h
> @@ -25,7 +25,7 @@ public:
>  
>  	int init(const YamlObject &tuningData) override;
>  	AwbResult calculateAwb(const AwbStats &stats, unsigned int lux) override;
> -	RGB<double> gainsFromColourTemperature(double colourTemperature) override;
> +	std::optional<RGB<double>> gainsFromColourTemperature(double colourTemperature) override;
>  
>  private:
>  	std::optional<Interpolator<Vector<double, 2>>> colourGainCurve_;
> diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
> index 5e067e50cd52..58b8370d2c61 100644
> --- a/src/ipa/rkisp1/algorithms/awb.cpp
> +++ b/src/ipa/rkisp1/algorithms/awb.cpp
> @@ -125,8 +125,12 @@ int Awb::configure(IPAContext &context,
>  		   const IPACameraSensorInfo &configInfo)
>  {
>  	context.activeState.awb.manual.gains = RGB<double>{ 1.0 };
> -	context.activeState.awb.automatic.gains =
> -		awbAlgo_->gainsFromColourTemperature(kDefaultColourTemperature);
> +	auto gains = awbAlgo_->gainsFromColourTemperature(kDefaultColourTemperature);
> +	if (gains)
> +		context.activeState.awb.automatic.gains = *gains;
> +	else
> +		context.activeState.awb.automatic.gains = RGB<double>{ 1.0 };
> +
>  	context.activeState.awb.autoEnabled = true;
>  	context.activeState.awb.manual.temperatureK = kDefaultColourTemperature;
>  	context.activeState.awb.automatic.temperatureK = kDefaultColourTemperature;
> @@ -184,10 +188,12 @@ void Awb::queueRequest(IPAContext &context,
>  		update = true;
>  	} else if (colourTemperature) {
>  		const auto &gains = awbAlgo_->gainsFromColourTemperature(*colourTemperature);
> -		awb.manual.gains.r() = gains.r();
> -		awb.manual.gains.b() = gains.b();
> +		if (gains) {
> +			awb.manual.gains.r() = gains->r();
> +			awb.manual.gains.b() = gains->b();
> +			update = true;
> +		}
>  		awb.manual.temperatureK = *colourTemperature;

Shouldn't we skip the colour temperature update too ?

> -		update = true;
>  	}
>  
>  	if (update)

-- 
Regards,

Laurent Pinchart