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

[Kieran Bingham]

Quoting Stefan Klug (2025-03-19 16:11:17)
> 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.

I tried to quibble on this but failed, so I think that means it seems
reasonable...


Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>

> 
> 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;
>  
>         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;
> -               update = true;
>         }
>  
>         if (update)
> -- 
> 2.43.0
>