[PATCH v5 13/18] libcamera: software_isp: Move black level to an algorithm module
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Sun Sep 1 23:03:38 CEST 2024
Hi Milan,
Thank you for the patch.
On Fri, Aug 30, 2024 at 09:25:49AM +0200, Milan Zamazal wrote:
> The black level determination, already present as a separate class, can
> be moved to the prepared Algorithm processing structure. It is the
> first of the current software ISP algorithms that is called in the stats
> processing sequence, which means it is also the first one that should be
> moved to the new structure. Stats processing starts with calling
> Algorithm-based processing so the call order of the algorithms is
> retained.
>
> Movement of this algorithm is relatively straightforward because all it
> does is processing stats.
>
> The comment about getting black level from the tuning files is dropped.
> The black level will be taken from CameraSensorHelper if available and
> that will be implemented in one of the followup patches.
>
> Black level is now recomputed on each stats processing. In a future
> patch, after DelayedControls are used, this will be changed to recompute
> the black level only after exposure/gain changes.
>
> Signed-off-by: Milan Zamazal <mzamazal at redhat.com>
> Reviewed-by: Umang Jain <umang.jain at ideasonboard.com>
> ---
> src/ipa/simple/algorithms/blc.cpp | 71 ++++++++++++++++++++
> src/ipa/simple/algorithms/blc.h | 37 +++++++++++
> src/ipa/simple/algorithms/meson.build | 1 +
> src/ipa/simple/black_level.cpp | 93 ---------------------------
> src/ipa/simple/black_level.h | 33 ----------
> src/ipa/simple/data/uncalibrated.yaml | 1 +
> src/ipa/simple/ipa_context.cpp | 8 +++
> src/ipa/simple/ipa_context.h | 5 ++
> src/ipa/simple/meson.build | 1 -
> src/ipa/simple/soft_simple.cpp | 8 +--
> 10 files changed, 125 insertions(+), 133 deletions(-)
> create mode 100644 src/ipa/simple/algorithms/blc.cpp
> create mode 100644 src/ipa/simple/algorithms/blc.h
> delete mode 100644 src/ipa/simple/black_level.cpp
> delete mode 100644 src/ipa/simple/black_level.h
>
> diff --git a/src/ipa/simple/algorithms/blc.cpp b/src/ipa/simple/algorithms/blc.cpp
> new file mode 100644
> index 00000000..3b73d830
> --- /dev/null
> +++ b/src/ipa/simple/algorithms/blc.cpp
> @@ -0,0 +1,71 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Red Hat Inc.
> + *
> + * Black level handling
> + */
> +
> +#include "blc.h"
> +
> +#include <numeric>
> +
> +#include <libcamera/base/log.h>
> +
> +namespace libcamera {
> +
> +namespace ipa::soft::algorithms {
> +
> +LOG_DEFINE_CATEGORY(IPASoftBL)
> +
> +BlackLevel::BlackLevel()
> +{
> +}
> +
> +int BlackLevel::init(IPAContext &context,
> + [[maybe_unused]] const YamlObject &tuningData)
> +{
> + context.activeState.black.level = 255;
Is init() the right place, shouldn't this be done in configure() ?
Setting the initial value in init() means that a new capture session
will not start with a reinitialized black level value.
> + return 0;
> +}
> +
> +void BlackLevel::process(IPAContext &context,
> + [[maybe_unused]] const uint32_t frame,
> + [[maybe_unused]] IPAFrameContext &frameContext,
> + const SwIspStats *stats,
> + [[maybe_unused]] ControlList &metadata)
> +{
> + const SwIspStats::Histogram &histogram = stats->yHistogram;
> +
> + /*
> + * The constant is selected to be "good enough", not overly conservative or
> + * aggressive. There is no magic about the given value.
Please reflow to 80 columns.
> + */
> + constexpr float ignoredPercentage_ = 0.02;
It's not a member variable, so no trailing underscore.
> + const unsigned int total =
> + std::accumulate(begin(histogram), end(histogram), 0);
> + const unsigned int pixelThreshold = ignoredPercentage_ * total;
> + const unsigned int histogramRatio = 256 / SwIspStats::kYHistogramSize;
> + const unsigned int currentBlackIdx =
> + context.activeState.black.level / histogramRatio;
> +
> + for (unsigned int i = 0, seen = 0;
> + i < currentBlackIdx && i < SwIspStats::kYHistogramSize;
> + i++) {
> + seen += histogram[i];
> + if (seen >= pixelThreshold) {
> + context.activeState.black.level = i * histogramRatio;
> + LOG(IPASoftBL, Debug)
> + << "Auto-set black level: "
> + << i << "/" << SwIspStats::kYHistogramSize
> + << " (" << 100 * (seen - histogram[i]) / total << "% below, "
> + << 100 * seen / total << "% at or below)";
> + break;
> + }
> + };
> +}
> +
> +REGISTER_IPA_ALGORITHM(BlackLevel, "BlackLevel")
> +
> +} /* namespace ipa::soft::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/simple/algorithms/blc.h b/src/ipa/simple/algorithms/blc.h
> new file mode 100644
> index 00000000..2f73db52
> --- /dev/null
> +++ b/src/ipa/simple/algorithms/blc.h
> @@ -0,0 +1,37 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Red Hat Inc.
> + *
> + * Black level handling
> + */
> +
> +#pragma once
> +
> +#include <libcamera/controls.h>
> +
> +#include "libcamera/internal/software_isp/swisp_stats.h"
> +
> +#include "algorithm.h"
> +#include "ipa_context.h"
I think you can drop controls.h, swisp_stats.h and ipa_context.h.
They're included only for classes and structures that are part of the
Algorithm class API, so they're guaranteed to be included through
algorithm.h.
> +
> +namespace libcamera {
> +
> +namespace ipa::soft::algorithms {
> +
> +class BlackLevel : public Algorithm
> +{
> +public:
> + BlackLevel();
> + ~BlackLevel() = default;
> +
> + int init(IPAContext &context, const YamlObject &tuningData)
> + override;
> + void process(IPAContext &context, const uint32_t frame,
> + IPAFrameContext &frameContext,
> + const SwIspStats *stats,
> + ControlList &metadata) override;
> +};
> +
> +} /* namespace ipa::soft::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/simple/algorithms/meson.build b/src/ipa/simple/algorithms/meson.build
> index 31d26e43..1f63c220 100644
> --- a/src/ipa/simple/algorithms/meson.build
> +++ b/src/ipa/simple/algorithms/meson.build
> @@ -1,4 +1,5 @@
> # SPDX-License-Identifier: CC0-1.0
>
> soft_simple_ipa_algorithms = files([
> + 'blc.cpp',
> ])
> diff --git a/src/ipa/simple/black_level.cpp b/src/ipa/simple/black_level.cpp
> deleted file mode 100644
> index 37e0109c..00000000
> --- a/src/ipa/simple/black_level.cpp
> +++ /dev/null
> @@ -1,93 +0,0 @@
> -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> -/*
> - * Copyright (C) 2024, Red Hat Inc.
> - *
> - * black level handling
> - */
> -
> -#include "black_level.h"
> -
> -#include <numeric>
> -
> -#include <libcamera/base/log.h>
> -
> -namespace libcamera {
> -
> -LOG_DEFINE_CATEGORY(IPASoftBL)
> -
> -namespace ipa::soft {
> -
> -/**
> - * \class BlackLevel
> - * \brief Object providing black point level for software ISP
> - *
> - * Black level can be provided in hardware tuning files or, if no tuning file is
> - * available for the given hardware, guessed automatically, with less accuracy.
> - * As tuning files are not yet implemented for software ISP, BlackLevel
> - * currently provides only guessed black levels.
> - *
> - * This class serves for tracking black level as a property of the underlying
> - * hardware, not as means of enhancing a particular scene or image.
> - *
> - * The class is supposed to be instantiated for the given camera stream.
> - * The black level can be retrieved using BlackLevel::get() method. It is
> - * initially 0 and may change when updated using BlackLevel::update() method.
> - */
> -
> -BlackLevel::BlackLevel()
> - : blackLevel_(255), blackLevelSet_(false)
> -{
> -}
> -
> -/**
> - * \brief Return the current black level
> - *
> - * \return The black level, in the range from 0 (minimum) to 255 (maximum).
> - * If the black level couldn't be determined yet, return 0.
> - */
> -uint8_t BlackLevel::get() const
> -{
> - return blackLevelSet_ ? blackLevel_ : 0;
> -}
> -
> -/**
> - * \brief Update black level from the provided histogram
> - * \param[in] yHistogram The histogram to be used for updating black level
> - *
> - * The black level is property of the given hardware, not image. It is updated
> - * only if it has not been yet set or if it is lower than the lowest value seen
> - * so far.
> - */
> -void BlackLevel::update(SwIspStats::Histogram &yHistogram)
> -{
> - /*
> - * The constant is selected to be "good enough", not overly conservative or
> - * aggressive. There is no magic about the given value.
> - */
> - constexpr float ignoredPercentage_ = 0.02;
> - const unsigned int total =
> - std::accumulate(begin(yHistogram), end(yHistogram), 0);
> - const unsigned int pixelThreshold = ignoredPercentage_ * total;
> - const unsigned int histogramRatio = 256 / SwIspStats::kYHistogramSize;
> - const unsigned int currentBlackIdx = blackLevel_ / histogramRatio;
> -
> - for (unsigned int i = 0, seen = 0;
> - i < currentBlackIdx && i < SwIspStats::kYHistogramSize;
> - i++) {
> - seen += yHistogram[i];
> - if (seen >= pixelThreshold) {
> - blackLevel_ = i * histogramRatio;
> - blackLevelSet_ = true;
> - LOG(IPASoftBL, Debug)
> - << "Auto-set black level: "
> - << i << "/" << SwIspStats::kYHistogramSize
> - << " (" << 100 * (seen - yHistogram[i]) / total << "% below, "
> - << 100 * seen / total << "% at or below)";
> - break;
> - }
> - };
> -}
> -
> -} /* namespace ipa::soft */
> -
> -} /* namespace libcamera */
> diff --git a/src/ipa/simple/black_level.h b/src/ipa/simple/black_level.h
> deleted file mode 100644
> index a04230c9..00000000
> --- a/src/ipa/simple/black_level.h
> +++ /dev/null
> @@ -1,33 +0,0 @@
> -/* SPDX-License-Identifier: LGPL-2.1-or-later */
> -/*
> - * Copyright (C) 2024, Red Hat Inc.
> - *
> - * black level handling
> - */
> -
> -#pragma once
> -
> -#include <array>
> -#include <stdint.h>
> -
> -#include "libcamera/internal/software_isp/swisp_stats.h"
> -
> -namespace libcamera {
> -
> -namespace ipa::soft {
> -
> -class BlackLevel
> -{
> -public:
> - BlackLevel();
> - uint8_t get() const;
> - void update(SwIspStats::Histogram &yHistogram);
> -
> -private:
> - uint8_t blackLevel_;
> - bool blackLevelSet_;
> -};
> -
> -} /* namespace ipa::soft */
> -
> -} /* namespace libcamera */
> diff --git a/src/ipa/simple/data/uncalibrated.yaml b/src/ipa/simple/data/uncalibrated.yaml
> index 2cdc39a8..e0d03d96 100644
> --- a/src/ipa/simple/data/uncalibrated.yaml
> +++ b/src/ipa/simple/data/uncalibrated.yaml
> @@ -3,4 +3,5 @@
> ---
> version: 1
> algorithms:
> + - BlackLevel:
> ...
> diff --git a/src/ipa/simple/ipa_context.cpp b/src/ipa/simple/ipa_context.cpp
> index 3c1c7262..268cff32 100644
> --- a/src/ipa/simple/ipa_context.cpp
> +++ b/src/ipa/simple/ipa_context.cpp
> @@ -50,4 +50,12 @@ namespace libcamera::ipa::soft {
> * \brief The current state of IPA algorithms
> */
>
> +/**
> + * \var IPAActiveState::black
> + * \brief Context for the Black Level algorithm
> + *
> + * \var IPAActiveState::black.level
> + * \brief Current determined black level
> + */
> +
> } /* namespace libcamera::ipa::soft */
> diff --git a/src/ipa/simple/ipa_context.h b/src/ipa/simple/ipa_context.h
> index e7d8b8df..22156569 100644
> --- a/src/ipa/simple/ipa_context.h
> +++ b/src/ipa/simple/ipa_context.h
> @@ -7,6 +7,8 @@
>
> #pragma once
>
> +#include <stdint.h>
> +
> #include <libipa/fc_queue.h>
>
> namespace libcamera {
> @@ -17,6 +19,9 @@ struct IPASessionConfiguration {
> };
>
> struct IPAActiveState {
> + struct {
> + uint8_t level;
> + } black;
How about naming this blc ?
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> };
>
> struct IPAFrameContext : public FrameContext {
> diff --git a/src/ipa/simple/meson.build b/src/ipa/simple/meson.build
> index dcd7c70a..2f9f15f4 100644
> --- a/src/ipa/simple/meson.build
> +++ b/src/ipa/simple/meson.build
> @@ -8,7 +8,6 @@ ipa_name = 'ipa_soft_simple'
> soft_simple_sources = files([
> 'ipa_context.cpp',
> 'soft_simple.cpp',
> - 'black_level.cpp',
> ])
>
> soft_simple_sources += soft_simple_ipa_algorithms
> diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
> index 4b9201dc..a1bd2f0c 100644
> --- a/src/ipa/simple/soft_simple.cpp
> +++ b/src/ipa/simple/soft_simple.cpp
> @@ -29,7 +29,6 @@
>
> #include "libipa/camera_sensor_helper.h"
>
> -#include "black_level.h"
> #include "module.h"
>
> namespace libcamera {
> @@ -61,7 +60,7 @@ class IPASoftSimple : public ipa::soft::IPASoftInterface, public Module
> {
> public:
> IPASoftSimple()
> - : params_(nullptr), stats_(nullptr), blackLevel_(BlackLevel()),
> + : params_(nullptr), stats_(nullptr),
> context_({ {}, {}, { kMaxFrameContexts } }),
> ignoreUpdates_(0)
> {
> @@ -93,7 +92,6 @@ private:
> SwIspStats *stats_;
> std::unique_ptr<CameraSensorHelper> camHelper_;
> ControlInfoMap sensorInfoMap_;
> - BlackLevel blackLevel_;
>
> static constexpr unsigned int kGammaLookupSize = 1024;
> std::array<uint8_t, kGammaLookupSize> gammaTable_;
> @@ -303,9 +301,7 @@ void IPASoftSimple::processStats(const uint32_t frame,
> algo->process(context_, frame, frameContext, stats_, metadata);
>
> SwIspStats::Histogram histogram = stats_->yHistogram;
> - if (ignoreUpdates_ > 0)
> - blackLevel_.update(histogram);
> - const uint8_t blackLevel = blackLevel_.get();
> + const uint8_t blackLevel = context_.activeState.black.level;
>
> /*
> * Black level must be subtracted to get the correct AWB ratios, they
--
Regards,
Laurent Pinchart
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