[libcamera-devel] [PATCH v2 08/10] ipa: raspberrypi: Generalise the agc algorithm

[Kieran Bingham]

Quoting Naushir Patuck via libcamera-devel (2023-03-27 13:20:28)
> Remove any hard-coded assumptions about the target hardware platform
> from the AGC algorithm. Instead, use the "target" string provided by
> the camera tuning config and generalised statistics structures to
> determing parameters such as grid and region sizes.
> 
> This change replaces all hard-coded arrays with equivalent std::vector
> types.
> 
> Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
> Reviewed-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>

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

> ---
>  src/ipa/raspberrypi/controller/rpi/agc.cpp | 20 +++++++++++++-------
>  src/ipa/raspberrypi/controller/rpi/agc.h   |  9 +--------
>  2 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/src/ipa/raspberrypi/controller/rpi/agc.cpp b/src/ipa/raspberrypi/controller/rpi/agc.cpp
> index 4ea0dd41e66c..fb96bb556e84 100644
> --- a/src/ipa/raspberrypi/controller/rpi/agc.cpp
> +++ b/src/ipa/raspberrypi/controller/rpi/agc.cpp
> @@ -31,17 +31,12 @@ LOG_DEFINE_CATEGORY(RPiAgc)
>  int AgcMeteringMode::read(const libcamera::YamlObject &params)
>  {
>         const YamlObject &yamlWeights = params["weights"];
> -       if (yamlWeights.size() != AgcStatsSize) {
> -               LOG(RPiAgc, Error) << "AgcMeteringMode: Incorrect number of weights";
> -               return -EINVAL;
> -       }
>  
> -       unsigned int num = 0;
>         for (const auto &p : yamlWeights.asList()) {
>                 auto value = p.get<double>();
>                 if (!value)
>                         return -EINVAL;
> -               weights[num++] = *value;
> +               weights.push_back(*value);
>         }
>  
>         return 0;
> @@ -249,6 +244,14 @@ int Agc::read(const libcamera::YamlObject &params)
>         if (ret)
>                 return ret;
>  
> +       const Size &size = getHardwareConfig().agcZoneWeights;
> +       for (auto const &modes : config_.meteringModes) {
> +               if (modes.second.weights.size() != size.width * size.height) {
> +                       LOG(RPiAgc, Error) << "AgcMeteringMode: Incorrect number of weights";
> +                       return -EINVAL;
> +               }
> +       }
> +
>         /*
>          * Set the config's defaults (which are the first ones it read) as our
>          * current modes, until someone changes them.  (they're all known to
> @@ -582,9 +585,12 @@ void Agc::fetchAwbStatus(Metadata *imageMetadata)
>  }
>  
>  static double computeInitialY(StatisticsPtr &stats, AwbStatus const &awb,
> -                             double weights[], double gain)
> +                             std::vector<double> &weights, double gain)
>  {
>         constexpr uint64_t maxVal = 1 << Statistics::NormalisationFactorPow2;
> +
> +       ASSERT(weights.size() == stats->agcRegions.numRegions());
> +
>         /*
>          * Note how the calculation below means that equal weights give you
>          * "average" metering (i.e. all pixels equally important).
> diff --git a/src/ipa/raspberrypi/controller/rpi/agc.h b/src/ipa/raspberrypi/controller/rpi/agc.h
> index f04896ca25ad..d11a49c9cd85 100644
> --- a/src/ipa/raspberrypi/controller/rpi/agc.h
> +++ b/src/ipa/raspberrypi/controller/rpi/agc.h
> @@ -17,17 +17,10 @@
>  
>  /* This is our implementation of AGC. */
>  
> -/*
> - * This is the number actually set up by the firmware, not the maximum possible
> - * number (which is 16).
> - */
> -
> -constexpr unsigned int AgcStatsSize = 15;
> -
>  namespace RPiController {
>  
>  struct AgcMeteringMode {
> -       double weights[AgcStatsSize];
> +       std::vector<double> weights;
>         int read(const libcamera::YamlObject &params);
>  };
>  
> -- 
> 2.34.1
>