[PATCH v3 2/6] ipa: ipu3: Use centralised libipa helpers

[Kieran Bingham]

Quoting Daniel Scally (2024-11-15 07:46:24)
> Use the centralised libipa helpers instead of open coding common
> functions.
> 
> Signed-off-by: Daniel Scally <dan.scally at ideasonboard.com>
> ---
> Changes in v3:
> 
>         - None
> 
> Changes in v2:
> 
>         - Dropped the ipa:: prefix for function calls
> 
>  src/ipa/ipu3/algorithms/agc.cpp |  7 ++++---
>  src/ipa/ipu3/algorithms/awb.cpp | 32 ++------------------------------
>  src/ipa/ipu3/algorithms/awb.h   |  1 -
>  3 files changed, 6 insertions(+), 34 deletions(-)
> 
> diff --git a/src/ipa/ipu3/algorithms/agc.cpp b/src/ipa/ipu3/algorithms/agc.cpp
> index c5f3d8f0..466b3fb3 100644
> --- a/src/ipa/ipu3/algorithms/agc.cpp
> +++ b/src/ipa/ipu3/algorithms/agc.cpp
> @@ -17,6 +17,7 @@
>  
>  #include <libcamera/ipa/core_ipa_interface.h>
>  
> +#include "libipa/colours.h"
>  #include "libipa/histogram.h"
>  
>  /**
> @@ -185,9 +186,9 @@ double Agc::estimateLuminance(double gain) const
>                 blueSum += std::min(std::get<2>(rgbTriples_[i]) * gain, 255.0);
>         }
>  
> -       double ySum = redSum * rGain_ * 0.299
> -                   + greenSum * gGain_ * 0.587
> -                   + blueSum * bGain_ * 0.114;
> +       double ySum = rec601LuminanceFromRGB(redSum * rGain_,
> +                                            greenSum * gGain_,
> +                                            blueSum * bGain_);


\o/


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

>  
>         return ySum / (bdsGrid_.height * bdsGrid_.width) / 255;
>  }
> diff --git a/src/ipa/ipu3/algorithms/awb.cpp b/src/ipa/ipu3/algorithms/awb.cpp
> index 4d6e3994..c3c8b074 100644
> --- a/src/ipa/ipu3/algorithms/awb.cpp
> +++ b/src/ipa/ipu3/algorithms/awb.cpp
> @@ -13,6 +13,8 @@
>  
>  #include <libcamera/control_ids.h>
>  
> +#include "libipa/colours.h"
> +
>  /**
>   * \file awb.h
>   */
> @@ -301,36 +303,6 @@ void Awb::prepare(IPAContext &context,
>         params->use.acc_ccm = 1;
>  }
>  
> -/**
> - * The function estimates the correlated color temperature using
> - * from RGB color space input.
> - * In physics and color science, the Planckian locus or black body locus is
> - * the path or locus that the color of an incandescent black body would take
> - * in a particular chromaticity space as the blackbody temperature changes.
> - *
> - * If a narrow range of color temperatures is considered (those encapsulating
> - * daylight being the most practical case) one can approximate the Planckian
> - * locus in order to calculate the CCT in terms of chromaticity coordinates.
> - *
> - * More detailed information can be found in:
> - * https://en.wikipedia.org/wiki/Color_temperature#Approximation
> - */
> -uint32_t Awb::estimateCCT(double red, double green, double blue)
> -{
> -       /* Convert the RGB values to CIE tristimulus values (XYZ) */
> -       double X = (-0.14282) * (red) + (1.54924) * (green) + (-0.95641) * (blue);
> -       double Y = (-0.32466) * (red) + (1.57837) * (green) + (-0.73191) * (blue);
> -       double Z = (-0.68202) * (red) + (0.77073) * (green) + (0.56332) * (blue);
> -
> -       /* Calculate the normalized chromaticity values */
> -       double x = X / (X + Y + Z);
> -       double y = Y / (X + Y + Z);
> -
> -       /* Calculate CCT */
> -       double n = (x - 0.3320) / (0.1858 - y);
> -       return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33;
> -}
> -
>  /* Generate an RGB vector with the average values for each zone */
>  void Awb::generateZones()
>  {
> diff --git a/src/ipa/ipu3/algorithms/awb.h b/src/ipa/ipu3/algorithms/awb.h
> index c0202823..a13c49ac 100644
> --- a/src/ipa/ipu3/algorithms/awb.h
> +++ b/src/ipa/ipu3/algorithms/awb.h
> @@ -75,7 +75,6 @@ private:
>         void generateAwbStats(const ipu3_uapi_stats_3a *stats);
>         void clearAwbStats();
>         void awbGreyWorld();
> -       uint32_t estimateCCT(double red, double green, double blue);
>         static constexpr uint16_t threshold(float value);
>         static constexpr uint16_t gainValue(double gain);
>  
> -- 
> 2.30.2
>