[PATCH v4 3/3] ipa: rkisp1: Add GammaOutCorrection algorithm

Stefan Klug stefan.klug at ideasonboard.com
Thu Jun 6 08:25:05 CEST 2024


Hi,

I missed the changelog on this one. So here it goes...

On Wed, Jun 05, 2024 at 11:53:51AM +0200, Stefan Klug wrote:
> Add a gamma algorithm for the rkisp1. It defaults to a gamma of 2.2 which
> closely resembles sRGB.  No seperate sRGB mode was implemented because the pwl
> that models the gamma curve is so coarse that there is basically no difference
> between srgb and gamma=2.2. The default can be overridden within the tuning
> file or set at runtime using the gamma control.
> 
> The gamma algorithm is not enabled by default. This will be done in future
> tuning file updates.
> 
> Signed-off-by: Stefan Klug <stefan.klug at ideasonboard.com>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
> ---

v3 -> v4:
- Changed structure in IPAActiveState and IPAFrameContext to be in line with 
  the other algorithms.
- Changed the logic to check if hw needs updating to a bool inside frameContext 
  to be in line with the other algorithms

v2 -> v3:
- Squashed with patch 1/4 from previous series
- Renamed from Gamma to GammaOutCorrection
- Read default gamma value from tuning file
- Some stylistic fixes from review

>  src/ipa/rkisp1/algorithms/goc.cpp     | 153 ++++++++++++++++++++++++++
>  src/ipa/rkisp1/algorithms/goc.h       |  42 +++++++
>  src/ipa/rkisp1/algorithms/meson.build |   1 +
>  src/ipa/rkisp1/ipa_context.h          |   9 ++
>  4 files changed, 205 insertions(+)
>  create mode 100644 src/ipa/rkisp1/algorithms/goc.cpp
>  create mode 100644 src/ipa/rkisp1/algorithms/goc.h
> 
> diff --git a/src/ipa/rkisp1/algorithms/goc.cpp b/src/ipa/rkisp1/algorithms/goc.cpp
> new file mode 100644
> index 000000000000..ab634c1c9709
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/goc.cpp
> @@ -0,0 +1,153 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Ideas On Board
> + *
> + * RkISP1 Gamma out control
> + */
> +#include "goc.h"
> +
> +#include <cmath>
> +
> +#include <libcamera/base/log.h>
> +#include <libcamera/base/utils.h>
> +
> +#include <libcamera/control_ids.h>
> +
> +#include "libcamera/internal/yaml_parser.h"
> +
> +#include "linux/rkisp1-config.h"
> +
> +/**
> + * \file goc.h
> + */
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +/**
> + * \class GammaOutCorrection
> + * \brief RkISP1 Gamma out correction
> + *
> + * This algorithm implements the gamma out curve for the RkISP1.
> + * It defaults to a gamma value of 2.2
> + * As gamma is internally represented as a piecewise linear function with only
> + * 17 knots, the difference between gamma=2.2 and sRGB gamma is minimal.
> + * Therefore sRGB gamma was not implemented as special case.
> + *
> + * Useful links:
> + * https://www.cambridgeincolour.com/tutorials/gamma-correction.htm
> + * https://en.wikipedia.org/wiki/SRGB
> + */
> +
> +LOG_DEFINE_CATEGORY(RkISP1Gamma)
> +
> +const float kDefaultGamma = 2.2f;
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::init
> + */
> +int GammaOutCorrection::init([[maybe_unused]] IPAContext &context,
> +			     [[maybe_unused]] const YamlObject &tuningData)
> +{
> +	if (context.hw->numGammaOutSamples !=
> +	    RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10) {
> +		LOG(RkISP1Gamma, Error)
> +			<< "Gamma is not implemented for RkISP1 V12";
> +		return -EINVAL;
> +	}
> +
> +	context.ctrlMap[&controls::Gamma] = ControlInfo(0.1f, 10.0f, kDefaultGamma);
> +	defaultGamma_ = tuningData["gamma"].get<double>(kDefaultGamma);
> +
> +	return 0;
> +}
> +
> +/**
> + * \brief Configure the Gamma given a configInfo
> + * \param[in] context The shared IPA context
> + * \param[in] configInfo The IPA configuration data
> + *
> + * \return 0
> + */
> +int GammaOutCorrection::configure(IPAContext &context,
> +				  [[maybe_unused]] const IPACameraSensorInfo &configInfo)
> +{
> +	context.activeState.goc.gamma = defaultGamma_;
> +	return 0;
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::queueRequest
> + */
> +void GammaOutCorrection::queueRequest([[maybe_unused]] IPAContext &context,
> +				      [[maybe_unused]] const uint32_t frame,
> +				      IPAFrameContext &frameContext,
> +				      const ControlList &controls)
> +{
> +	if (frame == 0)
> +		frameContext.goc.update = true;
> +
> +	const auto &gamma = controls.get(controls::Gamma);
> +	if (gamma) {
> +		context.activeState.goc.gamma = *gamma;
> +		frameContext.goc.update = true;
> +		LOG(RkISP1Gamma, Debug) << "Set gamma to " << *gamma;
> +	}
> +
> +	frameContext.goc.gamma = context.activeState.goc.gamma;
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::prepare
> + */
> +void GammaOutCorrection::prepare([[maybe_unused]] IPAContext &context,
> +				 [[maybe_unused]] const uint32_t frame,
> +				 [[maybe_unused]] IPAFrameContext &frameContext,
> +				 rkisp1_params_cfg *params)
> +{
> +	ASSERT(context.hw->numGammaOutSamples ==
> +	       RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10);
> +
> +	/*
> +	 * The logarithmic segments as specified in the reference.
> +	 * Plus an additional 0 to make the loop easier
> +	 */
> +	std::array<unsigned, RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10> segments = {
> +		64, 64, 64, 64, 128, 128, 128, 128, 256,
> +		256, 256, 512, 512, 512, 512, 512, 0
> +	};
> +	auto gamma_y = params->others.goc_config.gamma_y;
> +
> +	if (!frameContext.goc.update)
> +		return;
> +
> +	unsigned x = 0;
> +	for (const auto [i, size] : utils::enumerate(segments)) {
> +		gamma_y[i] = std::pow(x / 4096.0, 1.0 / frameContext.goc.gamma) * 1023.0;
> +		x += size;
> +	}
> +
> +	params->others.goc_config.mode = RKISP1_CIF_ISP_GOC_MODE_LOGARITHMIC;
> +	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_GOC;
> +	params->module_en_update |= RKISP1_CIF_ISP_MODULE_GOC;
> +	params->module_ens |= RKISP1_CIF_ISP_MODULE_GOC;
> +}
> +
> +/**
> + * \copydoc libcamera::ipa::Algorithm::process
> + */
> +void GammaOutCorrection::process([[maybe_unused]] IPAContext &context,
> +				 [[maybe_unused]] const uint32_t frame,
> +				 IPAFrameContext &frameContext,
> +				 [[maybe_unused]] const rkisp1_stat_buffer *stats,
> +				 ControlList &metadata)
> +{
> +	metadata.set(controls::Gamma, frameContext.goc.gamma);
> +}
> +
> +REGISTER_IPA_ALGORITHM(GammaOutCorrection, "GammaOutCorrection")
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/goc.h b/src/ipa/rkisp1/algorithms/goc.h
> new file mode 100644
> index 000000000000..3be8e500be67
> --- /dev/null
> +++ b/src/ipa/rkisp1/algorithms/goc.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2024, Ideas On Board
> + *
> + * RkISP1 Gamma out control
> + */
> +
> +#pragma once
> +
> +#include "algorithm.h"
> +
> +namespace libcamera {
> +
> +namespace ipa::rkisp1::algorithms {
> +
> +class GammaOutCorrection : public Algorithm
> +{
> +public:
> +	GammaOutCorrection() = default;
> +	~GammaOutCorrection() = default;
> +
> +	int init(IPAContext &context, const YamlObject &tuningData) override;
> +	int configure(IPAContext &context,
> +		      const IPACameraSensorInfo &configInfo) override;
> +	void queueRequest(IPAContext &context,
> +			  const uint32_t frame,
> +			  IPAFrameContext &frameContext,
> +			  const ControlList &controls) override;
> +	void prepare(IPAContext &context, const uint32_t frame,
> +		     IPAFrameContext &frameContext,
> +		     rkisp1_params_cfg *params) override;
> +	void process(IPAContext &context, const uint32_t frame,
> +		     IPAFrameContext &frameContext,
> +		     const rkisp1_stat_buffer *stats,
> +		     ControlList &metadata) override;
> +
> +private:
> +	double defaultGamma_;
> +};
> +
> +} /* namespace ipa::rkisp1::algorithms */
> +} /* namespace libcamera */
> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> index 93a483292753..6ee71a9b5da3 100644
> --- a/src/ipa/rkisp1/algorithms/meson.build
> +++ b/src/ipa/rkisp1/algorithms/meson.build
> @@ -8,6 +8,7 @@ rkisp1_ipa_algorithms = files([
>      'dpcc.cpp',
>      'dpf.cpp',
>      'filter.cpp',
> +    'goc.cpp',
>      'gsl.cpp',
>      'lsc.cpp',
>  ])
> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> index bd02a7a24fdd..f261e42fc2fd 100644
> --- a/src/ipa/rkisp1/ipa_context.h
> +++ b/src/ipa/rkisp1/ipa_context.h
> @@ -104,6 +104,10 @@ struct IPAActiveState {
>  		uint8_t denoise;
>  		uint8_t sharpness;
>  	} filter;
> +
> +	struct {
> +		double gamma;
> +	} goc;
>  };
>  
>  struct IPAFrameContext : public FrameContext {
> @@ -146,6 +150,11 @@ struct IPAFrameContext : public FrameContext {
>  		uint32_t exposure;
>  		double gain;
>  	} sensor;
> +
> +	struct {
> +		double gamma;
> +		bool update;
> +	} goc;
>  };
>  
>  struct IPAContext {
> -- 
> 2.43.0
> 


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