[PATCH v2 2/2] ipa: rkisp1: Add Lux algorithm module

[Kieran Bingham]

Quoting Paul Elder (2024-12-16 09:49:33)
> Add a lux algorithm module to rkisp1 IPA for estimating the lux level of
> an image. This is reported in metadata, as well as saved in the frame
> context so that other algorithms (mainly AGC) can use its value. It does
> not set any controls.
> 
> Signed-off-by: Paul Elder <paul.elder at ideasonboard.com>
> 
> ---
> Changes in v2:
> - fix bitrot
> - fixes corresponding to changes in the previous patch
> ---
>  src/ipa/rkisp1/algorithms/lux.cpp     | 76 +++++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/lux.h       | 39 ++++++++++++++
>  src/ipa/rkisp1/algorithms/meson.build |  1 +
>  src/ipa/rkisp1/ipa_context.h          |  1 +
>  4 files changed, 117 insertions(+)
>  create mode 100644 src/ipa/rkisp1/algorithms/lux.cpp
>  create mode 100644 src/ipa/rkisp1/algorithms/lux.h
> 
> diff --git a/src/ipa/rkisp1/algorithms/lux.cpp b/src/ipa/rkisp1/algorithms/lux.cpp
> new file mode 100644
> index 000000000000..333167b15f64
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/lux.cpp
> @@ -0,0 +1,76 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Ideas On Board
> + *
> + * lux.cpp - RkISP1 Lux control
> + */
> +
> +#include "lux.h"
> +
> +#include <algorithm>
> +#include <cmath>
> +
> +#include <libcamera/base/log.h>
> +
> +#include <libcamera/control_ids.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "libipa/histogram.h"
> +#include "libipa/lux.h"
> +
> +/**
> + * \file lux.h
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +/**
> + * \class Lux
> + * \brief RkISP1 Lux control
> + *
> + * The Lux algorithm is responsible for estimating the lux level of the image.
> + * It doesn't take or generate any controls, but it provides a lux level for
> + * other algorithms (such as AGC) to use.
> + */
> +
> +LOG_DEFINE_CATEGORY(RkISP1Lux)
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::init
> + */
> +int Lux::init([[maybe_unused]] IPAContext &context, const YamlObject &tuningData)
> +{
> +       lux_.setBinSize(65535);
> +       return lux_.readYaml(tuningData);
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::process
> + */
> +void Lux::process(IPAContext &context,
> +                 [[maybe_unused]] const uint32_t frame,
> +                 IPAFrameContext &frameContext,
> +                 const rkisp1_stat_buffer *stats,
> +                 ControlList &metadata)
> +{
> +       utils::Duration exposureTime = context.configuration.sensor.lineDuration
> +                                      * frameContext.sensor.exposure;
> +       double gain = frameContext.sensor.gain;
> +
> +       const rkisp1_cif_isp_stat *params = &stats->params;
> +       Histogram yHist({ params->hist.hist_bins, context.hw->numHistogramBins },
> +                       [](uint32_t x) { return x >> 4; });
> +
> +       double lux = lux_.estimateLux(exposureTime, gain, 1.0, yHist);
> +       frameContext.agc.lux = lux;
> +       metadata.set(controls::Lux, lux);
> +}
> +
> +REGISTER_IPA_ALGORITHM(Lux, "Lux")
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/lux.h b/src/ipa/rkisp1/algorithms/lux.h
> new file mode 100644
> index 000000000000..ea98c29120eb
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/lux.h
> @@ -0,0 +1,39 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Ideas On Board
> + *
> + * lux.h - RkISP1 Lux control
> + */
> +
> +#pragma once
> +
> +#include <sys/types.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "libipa/lux.h"
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +class Lux : public Algorithm
> +{
> +public:
> +       Lux() = default;
> +       ~Lux() = default;
> +
> +       int init(IPAContext &context, const YamlObject &tuningData) override;
> +       void process(IPAContext &context, const uint32_t frame,
> +                    IPAFrameContext &frameContext,
> +                    const rkisp1_stat_buffer *stats,
> +                    ControlList &metadata) override;
> +
> +private:
> +       ipa::Lux lux_;
> +};
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> index 1734a6675f78..c66b0b70b82f 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -12,4 +12,5 @@ rkisp1_ipa_algorithms = files([
>      'goc.cpp',
>      'gsl.cpp',
>      'lsc.cpp',
> +    'lux.cpp',
>  ])
> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> index deb8c196f1b8..e7bdc51bfa4c 100644
> --- a/src/ipa/rkisp1/ipa_context.h
> +++ b/src/ipa/rkisp1/ipa_context.h
> @@ -130,6 +130,7 @@ struct IPAFrameContext : public FrameContext {
>                 controls::AeMeteringModeEnum meteringMode;
>                 utils::Duration maxFrameDuration;
>                 bool updateMetering;
> +               double lux;

Is this really part of agc ? Is it used anywhere that it needs to be
stored in the FrameContext? (Or will it be used somewhere?)

I'm curious on what it will be used for and whether we need to guarantee
ordering that the lux runs before AGC if it's /really/ used by the AGC.

Perhaps not storing it for now would be easier until it's needed, as
then it would be clearer - but I don't object to storing it.

Does libtuning already prepare and store the lux calibration reference
points ?

--

>         } agc;
>  
>         struct {
> -- 
> 2.39.2
>