[libcamera-devel] [PATCH v5.1 10/11] ipa: rkisp1: Introduce AGC

Laurent Pinchart laurent.pinchart at ideasonboard.com
Mon Nov 29 16:42:02 CET 2021


Hi Jean-Michel,

On Mon, Nov 29, 2021 at 02:04:30PM +0100, Jean-Michel Hautbois wrote:
> On 26/11/2021 23:56, Laurent Pinchart wrote:
> > On Fri, Nov 26, 2021 at 05:43:01PM +0100, Jean-Michel Hautbois wrote:
> >> Now that we have IPAContext and Algorithm, we can implement a simple AGC
> >> based on the IPU3 one. It is very similar, except that there is no
> >> histogram used for an inter quantile mean. The RkISP1 is returning a 5x5
> >> array (for V10) of luminance means. Estimating the relative luminance is
> >> thus a simple mean of all the blocks already calculated by the ISP.
> >>
> >> Signed-off-by: Jean-Michel Hautbois <jeanmichel.hautbois at ideasonboard.com>
> >>
> >> ---
> >> v6:
> >> 	- Move lineDuration in a configuration.sensor structure in
> >> 	  IPAContext
> >> 	- Add a documentation for filterExposure()
> >> 	- Move shutterTime initialisation
> >> v5:
> >> 	- use private filteredExposure_ and pass currentExposure as a
> >> 	  member variable
> >> 	- Drop num and replace it with numCells_
> >> 	- Make exposure and gain local variables in IPARkISP1
> >> 	- Shorter the lines in processEvent()
> >> v4:
> >> 	- use #pragma once
> >> 	- Return filtered value from the function
> >> 	- Store line duration in IPASessionConfiguration
> >> 	- Use the hw revision to configure the number of AE cells
> >> ---
> >>   src/ipa/rkisp1/algorithms/agc.cpp     | 280 ++++++++++++++++++++++++++
> >>   src/ipa/rkisp1/algorithms/agc.h       |  46 +++++
> >>   src/ipa/rkisp1/algorithms/meson.build |   1 +
> >>   src/ipa/rkisp1/ipa_context.cpp        |  50 +++++
> >>   src/ipa/rkisp1/ipa_context.h          |  22 ++
> >>   src/ipa/rkisp1/rkisp1.cpp             |  83 ++++----
> >>   6 files changed, 438 insertions(+), 44 deletions(-)
> >>   create mode 100644 src/ipa/rkisp1/algorithms/agc.cpp
> >>   create mode 100644 src/ipa/rkisp1/algorithms/agc.h
> >>
> >> diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
> >> new file mode 100644
> >> index 00000000..55d7405a
> >> --- /dev/null
> >> +++ b/src/ipa/rkisp1/algorithms/agc.cpp
> >> @@ -0,0 +1,280 @@
> >> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> >> +/*
> >> + * Copyright (C) 2021, Ideas On Board
> >> + *
> >> + * agc.cpp - AGC/AEC mean-based control algorithm
> >> + */
> >> +
> >> +#include "agc.h"
> >> +
> >> +#include <algorithm>
> >> +#include <chrono>
> >> +#include <cmath>
> >> +
> >> +#include <libcamera/base/log.h>
> >> +
> >> +#include <libcamera/ipa/core_ipa_interface.h>
> >> +
> >> +/**
> >> + * \file agc.h
> >> + */
> >> +
> >> +namespace libcamera {
> >> +
> >> +using namespace std::literals::chrono_literals;
> >> +
> >> +namespace ipa::rkisp1::algorithms {
> >> +
> >> +/**
> >> + * \class Agc
> >> + * \brief A mean-based auto-exposure algorithm
> >> + */
> >> +
> >> +LOG_DEFINE_CATEGORY(RkISP1Agc)
> >> +
> >> +/* Limits for analogue gain values */
> >> +static constexpr double kMinAnalogueGain = 1.0;
> >> +static constexpr double kMaxAnalogueGain = 8.0;
> >> +
> >> +/* \todo Honour the FrameDurationLimits control instead of hardcoding a limit */
> >> +static constexpr utils::Duration kMaxShutterSpeed = 60ms;
> >> +
> >> +/* Number of frames to wait before calculating stats on minimum exposure */
> >> +static constexpr uint32_t kNumStartupFrames = 10;
> >> +
> >> +/*
> >> + * Relative luminance target.
> >> + *
> >> + * It's a number that's chosen so that, when the camera points at a grey
> >> + * target, the resulting image brightness is considered right.
> >> + */
> >> +static constexpr double kRelativeLuminanceTarget = 0.4;
> > 
> > This is much higher than for the IPU3, why is that ?
> 
> I am not yet sure why, but the measures I did on a grey target lead to 
> this value for the brightness to be correct. It is on my todo list to 
> understand why it is not the same for IPU3 and RkISP1 (is it related to 
> the sensor ? the ISP ? something else ? not sure yet)

Can you add a \todo comment ? I think it's also important enough to
record a task in the bug tracker.

> >> +
> >> +Agc::Agc()
> >> +	: frameCount_(0), filteredExposure_(0s)
> >> +{
> >> +}
> >> +
> >> +/**
> >> + * \brief Configure the AGC given a configInfo
> >> + * \param[in] context The shared IPA context
> >> + * \param[in] configInfo The IPA configuration data
> >> + *
> >> + * \return 0
> >> + */
> >> +int Agc::configure(IPAContext &context,
> >> +		   [[maybe_unused]] const IPACameraSensorInfo &configInfo)
> >> +{
> >> +	/* Configure the default exposure and gain. */
> >> +	context.frameContext.agc.gain = std::max(context.configuration.agc.minAnalogueGain, kMinAnalogueGain);
> >> +	context.frameContext.agc.exposure = 10ms / context.configuration.sensor.lineDuration;
> >> +
> >> +	/*
> >> +	 * According to the RkISP1 documentation:
> >> +	 * - versions <= V11 have RKISP1_CIF_ISP_AE_MEAN_MAX_V10 entries,
> > 
> > s/<= V11/< V12/
> 
> OK, but this is a strict copy/paste from the RkISP1 include file ;-).
> 
> >> +	 * - versions >= V12 have RKISP1_CIF_ISP_AE_MEAN_MAX_V12 entries.
> >> +	 */
> >> +	if (context.configuration.hw.revision < RKISP1_V12)
> >> +		numCells_ = RKISP1_CIF_ISP_AE_MEAN_MAX_V10;
> >> +	else
> >> +		numCells_ = RKISP1_CIF_ISP_AE_MEAN_MAX_V12;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +/**
> >> + * \brief Apply a filter on the exposure value to limit the speed of changes
> >> + * \param[in] currentExposure The target exposure from the AGC algorithm
> >> + * \return The filtered exposure
> > 
> > \return should go to the end.
> > 
> >> + *
> >> + * The speed of the filter is adaptive, and will produce the target quicker
> >> + * during startup, or when the target exposure is within 20% of the most recent
> >> + * filter output.
> >> + */
> >> +utils::Duration Agc::filterExposure(utils::Duration currentExposure)
> > 
> > I would s/currentExposure/exposure/ as it's not "current".
> 
> What about expectedExposure ?

>From the point of view of the filter, it's really just an input value.
You could name it inputExposure, I'm not sure it would make the code
easier to read.

> >> +{
> >> +	double speed = 0.2;
> >> +
> >> +	/* Adapt instantly if we are in startup phase */
> > 
> > s/phase/phase./ (and similarly through the rest of the file)
> > 
> >> +	if (frameCount_ < kNumStartupFrames)
> >> +		speed = 1.0;
> >> +
> >> +	if (filteredExposure_ == 0s) {
> >> +		filteredExposure_ = currentExposure;
> > 
> > Do we actually need this ? speed is set to 1.0 for the first frames,
> > which I expect is the only time when filteredExposure_ can be equal to
> > 0. This is something you can fix (if my analysis is correct) for both
> > IPU3 and RkISP1 on top of this series.
> 
> Indeed, thanks.
> 
> >> +	} else {
> >> +		/*
> >> +		 * If we are close to the desired result, go faster to avoid making
> >> +		 * multiple micro-adjustments.
> >> +		 * \todo Make this customisable?
> >> +		 */
> >> +		if (filteredExposure_ < 1.2 * currentExposure &&
> >> +		    filteredExposure_ > 0.8 * currentExposure)
> >> +			speed = sqrt(speed);
> >> +
> >> +		filteredExposure_ = speed * currentExposure +
> >> +				    filteredExposure_ * (1.0 - speed);
> >> +	}
> >> +
> >> +	LOG(RkISP1Agc, Debug) << "After filtering, total_exposure " << filteredExposure_;
> > 
> > s/total_exposure/exposure/ ?
> > 
> >> +
> >> +	return filteredExposure_;
> >> +}
> >> +
> >> +/**
> >> + * \brief Estimate the new exposure and gain values
> >> + * \param[inout] frameContext The shared IPA frame Context
> >> + * \param[in] yGain The gain calculated on the current brightness level
> >> + */
> >> +void Agc::computeExposure(IPAContext &context, double yGain)
> >> +{
> >> +	IPASessionConfiguration &configuration = context.configuration;
> >> +	IPAFrameContext &frameContext = context.frameContext;
> >> +
> >> +	/* Get the effective exposure and gain applied on the sensor. */
> >> +	uint32_t exposure = frameContext.sensor.exposure;
> >> +	double analogueGain = frameContext.sensor.gain;
> >> +
> >> +	utils::Duration minShutterSpeed = configuration.agc.minShutterSpeed;
> >> +	utils::Duration maxShutterSpeed = std::min(configuration.agc.maxShutterSpeed,
> >> +						   kMaxShutterSpeed);
> >> +
> >> +	double minAnalogueGain = std::max(configuration.agc.minAnalogueGain,
> >> +					  kMinAnalogueGain);
> >> +	double maxAnalogueGain = std::min(configuration.agc.maxAnalogueGain,
> >> +					  kMaxAnalogueGain);
> >> +
> >> +	/* Consider within 1% of the target as correctly exposed */
> >> +	if (std::abs(yGain - 1.0) < 0.01)
> >> +		LOG(RkISP1Agc, Debug) << "We are well exposed (iqMean = "
> >> +				      << yGain << ")";
> > 
> > This sounds like it will flood the logs without bringing much value, as
> > the yGain is printed below too. We used to return early in this case,
> > I'm not sure we we don't anymore. Also something we should address (if
> > desired) for IPU3 and RkISP1 on top.
> 
> You are right.
> 
> >> +
> >> +	/* extracted from Rpi::Agc::computeTargetExposure */
> >> +
> >> +	/* Calculate the shutter time in seconds */
> >> +	utils::Duration currentShutter = exposure * configuration.sensor.lineDuration;
> >> +
> >> +	/*
> >> +	 * Update the exposure value for the next computation using the values
> >> +	 * of exposure and gain really used by the sensor.
> >> +	 */
> >> +	utils::Duration effectiveExposureValue = currentShutter * analogueGain;
> >> +
> >> +	LOG(RkISP1Agc, Debug) << "Actual total exposure " << currentShutter * analogueGain
> >> +			      << " Shutter speed " << currentShutter
> >> +			      << " Gain " << analogueGain
> >> +			      << " Needed ev gain " << yGain;
> >> +
> >> +	/*
> >> +	 * Calculate the current exposure value for the scene as the latest
> >> +	 * exposure value applied multiplied by the new estimated gain.
> >> +	 */
> >> +	utils::Duration currentExposure = effectiveExposureValue * yGain;
> > 
> > s/currentExposure/exposureValue/ here and below.
> > 
> >> +
> >> +	/* Clamp the exposure value to the min and max authorized */
> >> +	utils::Duration maxTotalExposure = maxShutterSpeed * maxAnalogueGain;
> >> +	currentExposure = std::min(currentExposure, maxTotalExposure);
> >> +	LOG(RkISP1Agc, Debug) << "Target total exposure " << currentExposure
> >> +			      << ", maximum is " << maxTotalExposure;
> >> +
> >> +	/*
> >> +	 * Divide the exposure value as new exposure and gain values
> >> +	 * \todo: estimate if we need to desaturate
> > 
> > s/todo:/todo/
> > 
> >> +	 */
> >> +	utils::Duration exposureValue = filterExposure(currentExposure);
> >> +
> >> +	/*
> >> +	* Push the shutter time up to the maximum first, and only then
> >> +	* increase the gain.
> >> +	*/
> > 
> > Incorrect indentation.
> > 
> >> +	utils::Duration shutterTime = std::clamp<utils::Duration>(exposureValue / minAnalogueGain,
> >> +								  minShutterSpeed, maxShutterSpeed);
> >> +	double stepGain = std::clamp(exposureValue / shutterTime,
> >> +				     minAnalogueGain, maxAnalogueGain);
> >> +	LOG(RkISP1Agc, Debug) << "Divided up shutter and gain are "
> >> +			      << shutterTime << " and "
> >> +			      << stepGain;
> >> +
> >> +	/* Update the estimated exposure and gain. */
> >> +	frameContext.agc.exposure = shutterTime / configuration.sensor.lineDuration;
> >> +	frameContext.agc.gain = stepGain;
> >> +}
> >> +
> >> +/**
> >> + * \brief Estimate the relative luminance of the frame with a given gain
> >> + * \param[in] ae The RkISP1 statistics and ISP results
> >> + * \param[in] gain The gain calculated on the current brightness level
> > 
> >   * \param[in] gain The gain to apply to the frame
> > 
> >> + * \return The relative luminance
> >> + *
> >> + * This function estimates the average relative luminance of the frame that
> >> + * would be output by the sensor if an additional \a gain was applied.
> >> + *
> >> + * The estimation is based on the AE statistics for the current frame. Y
> >> + * averages for all cells are first multiplied by the gain, and then saturated
> >> + * to approximate the sensor behaviour at high brightness values. The
> >> + * approximation is quite rough, as it doesn't take into account non-linearities
> >> + * when approaching saturation.
> > 
> > It's actually worse than that in this case, as saturating after the
> > conversion to YUV also doesn't take into account the fact that the R, G
> > and B components contribute differently to the relative luminance. A
> > different algorithm may be better (not as part of this patch of course).

Could you also record this by the way ?

 * when approaching saturation, nor does it take into account the R, G and B
 * components saturating at the same levels but contributing differently to the
 * relative luminance.

> >> + *
> >> + * The values are normalized to the [0.0, 1.0] range, where 1.0 corresponds to a
> >> + * theoretical perfect reflector of 100% reference white.
> >> + *
> >> + * More detailed information can be found in:
> >> + * https://en.wikipedia.org/wiki/Relative_luminance
> >> + */
> >> +double Agc::estimateLuminance(const rkisp1_cif_isp_ae_stat *ae,
> >> +			      double gain)
> >> +{
> >> +	double ySum = 0.0;
> >> +
> >> +	/* Sum the averages, saturated to 255. */
> >> +	for (unsigned int aeCell = 0; aeCell < numCells_; aeCell++)
> >> +		ySum += std::min(ae->exp_mean[aeCell] * gain, 255.0);
> >> +
> >> +	/* \todo Weight with the AWB gains */
> 
> This could be why we don't have the same kRelativeLuminanceTarget BTW ;-).
> 
> >> +
> >> +	return ySum / numCells_ / 255;
> >> +}
> >> +
> >> +/**
> >> + * \brief Process RkISP1 statistics, and run AGC operations
> >> + * \param[in] context The shared IPA context
> >> + * \param[in] stats The RKIsp1 statistics and ISP results
> > 
> > s/RKIsp1/RkISP1/
> > 
> >> + *
> >> + * Identify the current image brightness, and use that to estimate the optimal
> >> + * new exposure and gain for the scene.
> >> + */
> >> +void Agc::process(IPAContext &context, const rkisp1_stat_buffer *stats)
> >> +{
> >> +	const rkisp1_cif_isp_stat *params = &stats->params;
> >> +	ASSERT(stats->meas_type & RKISP1_CIF_ISP_STAT_AUTOEXP);
> >> +
> >> +	const rkisp1_cif_isp_ae_stat *ae = &params->ae;
> >> +
> >> +	/*
> >> +	 * Estimate the gain needed to achieve a relative luminance target. To
> >> +	 * account for non-linearity caused by saturation, the value needs to be
> >> +	 * estimated in an iterative process, as multiplying by a gain will not
> >> +	 * increase the relative luminance by the same factor if some image
> >> +	 * regions are saturated.
> >> +	 */
> >> +	double yGain = 1.0;
> >> +	double yTarget = kRelativeLuminanceTarget;
> >> +
> >> +	for (unsigned int i = 0; i < 8; i++) {
> >> +		double yValue = estimateLuminance(ae, yGain);
> >> +		double extra_gain = std::min(10.0, yTarget / (yValue + .001));
> >> +
> >> +		yGain *= extra_gain;
> >> +		LOG(RkISP1Agc, Debug) << "Y value: " << yValue
> >> +				      << ", Y target: " << yTarget
> >> +				      << ", gives gain " << yGain;
> >> +		if (extra_gain < 1.01)
> >> +			break;
> >> +	}
> >> +
> >> +	computeExposure(context, yGain);
> >> +	frameCount_++;
> > 
> > frameCount_ is never reset to 0, is that expected ?
> 
> No :-(
> 
> >> +}
> >> +
> >> +} /* namespace ipa::rkisp1::algorithms */
> >> +
> >> +} /* namespace libcamera */
> >> diff --git a/src/ipa/rkisp1/algorithms/agc.h b/src/ipa/rkisp1/algorithms/agc.h
> >> new file mode 100644
> >> index 00000000..8ec172d7
> >> --- /dev/null
> >> +++ b/src/ipa/rkisp1/algorithms/agc.h
> >> @@ -0,0 +1,46 @@
> >> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> >> +/*
> >> + * Copyright (C) 2021, Ideas On Board
> >> + *
> >> + * agc.h - RkISP1 AGC/AEC mean-based control algorithm
> >> + */
> >> +
> >> +#pragma once
> >> +
> >> +#include <linux/rkisp1-config.h>
> >> +
> >> +#include <libcamera/base/utils.h>
> >> +
> >> +#include <libcamera/geometry.h>
> >> +
> >> +#include "algorithm.h"
> >> +
> >> +namespace libcamera {
> >> +
> >> +struct IPACameraSensorInfo;
> >> +
> >> +namespace ipa::rkisp1::algorithms {
> >> +
> >> +class Agc : public Algorithm
> >> +{
> >> +public:
> >> +	Agc();
> >> +	~Agc() = default;
> >> +
> >> +	int configure(IPAContext &context, const IPACameraSensorInfo &configInfo) override;
> >> +	void process(IPAContext &context, const rkisp1_stat_buffer *stats) override;
> >> +
> >> +private:
> >> +	void computeExposure(IPAContext &Context, double yGain);
> >> +	utils::Duration filterExposure(utils::Duration currentExposure);
> > 
> > s/currentExposure/exposure/ here too.
> > 
> >> +	double estimateLuminance(const rkisp1_cif_isp_ae_stat *ae, double gain);
> >> +
> >> +	uint64_t frameCount_;
> >> +
> >> +	uint32_t numCells_;
> >> +
> >> +	utils::Duration filteredExposure_;
> >> +};
> >> +
> >> +} /* namespace ipa::rkisp1::algorithms */
> >> +} /* namespace libcamera */
> >> diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
> >> index 1c6c59cf..a19c1a4f 100644
> >> --- a/src/ipa/rkisp1/algorithms/meson.build
> >> +++ b/src/ipa/rkisp1/algorithms/meson.build
> >> @@ -1,4 +1,5 @@
> >>   # SPDX-License-Identifier: CC0-1.0
> >>   
> >>   rkisp1_ipa_algorithms = files([
> >> +    'agc.cpp',
> >>   ])
> >> diff --git a/src/ipa/rkisp1/ipa_context.cpp b/src/ipa/rkisp1/ipa_context.cpp
> >> index 6b53dfdf..9cb2a9fd 100644
> >> --- a/src/ipa/rkisp1/ipa_context.cpp
> >> +++ b/src/ipa/rkisp1/ipa_context.cpp
> >> @@ -56,6 +56,21 @@ namespace libcamera::ipa::rkisp1 {
> >>    */
> >>   
> >>   /**
> >> + * \var IPASessionConfiguration::agc
> >> + * \brief AGC parameters configuration of the IPA
> >> + *
> >> + * \var IPASessionConfiguration::agc.minShutterSpeed
> >> + * \brief Minimum shutter speed supported with the configured sensor
> >> + *
> >> + * \var IPASessionConfiguration::agc.maxShutterSpeed
> >> + * \brief Maximum shutter speed supported with the configured sensor
> >> + *
> >> + * \var IPASessionConfiguration::agc.minAnalogueGain
> >> + * \brief Minimum analogue gain supported with the configured sensor
> >> + *
> >> + * \var IPASessionConfiguration::agc.maxAnalogueGain
> >> + * \brief Maximum analogue gain supported with the configured sensor
> >> + *
> >>    * \var IPASessionConfiguration::hw
> >>    * \brief RkISP1-specific hardware information
> >>    *
> >> @@ -63,4 +78,39 @@ namespace libcamera::ipa::rkisp1 {
> >>    * \brief Hardware revision of the ISP
> >>    */
> >>   
> >> +/**
> >> + * \var IPASessionConfiguration::sensor
> >> + * \brief Sensor-specific configuration of the IPA
> >> + *
> >> + * \var IPASessionConfiguration::sensor.lineDuration
> >> + * \brief Line duration in microseconds
> >> + */
> >> +
> >> +/**
> >> + * \var IPAFrameContext::agc
> >> + * \brief Context for the Automatic Gain Control algorithm
> >> + *
> >> + * The exposure and gain determined are expected to be applied to the sensor
> >> + * at the earliest opportunity.
> >> + *
> >> + * \var IPAFrameContext::agc.exposure
> >> + * \brief Exposure time expressed as a number of lines
> >> + *
> >> + * \var IPAFrameContext::agc.gain
> >> + * \brief Analogue gain multiplier
> >> + *
> >> + * The gain should be adapted to the sensor specific gain code before applying.
> >> + */
> >> +
> >> +/**
> >> + * \var IPAFrameContext::sensor
> >> + * \brief Effective sensor values
> >> + *
> >> + * \var IPAFrameContext::sensor.exposure
> >> + * \brief Exposure time expressed as a number of lines
> >> + *
> >> + * \var IPAFrameContext::sensor.gain
> >> + * \brief Analogue gain multiplier
> >> + */
> >> +
> >>   } /* namespace libcamera::ipa::rkisp1 */
> >> diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
> >> index 9342025b..b94ade0c 100644
> >> --- a/src/ipa/rkisp1/ipa_context.h
> >> +++ b/src/ipa/rkisp1/ipa_context.h
> >> @@ -10,17 +10,39 @@
> >>   
> >>   #include <linux/rkisp1-config.h>
> >>   
> >> +#include <libcamera/base/utils.h>
> >> +
> >>   namespace libcamera {
> >>   
> >>   namespace ipa::rkisp1 {
> >>   
> >>   struct IPASessionConfiguration {
> >> +	struct {
> >> +		utils::Duration minShutterSpeed;
> >> +		utils::Duration maxShutterSpeed;
> >> +		double minAnalogueGain;
> >> +		double maxAnalogueGain;
> >> +	} agc;
> >> +
> >> +	struct {
> >> +		utils::Duration lineDuration;
> >> +	} sensor;
> >> +
> >>   	struct {
> >>   		rkisp1_cif_isp_version revision;
> >>   	} hw;
> >>   };
> >>   
> >>   struct IPAFrameContext {
> >> +	struct {
> >> +		uint32_t exposure;
> >> +		double gain;
> >> +	} agc;
> >> +
> >> +	struct {
> >> +		uint32_t exposure;
> >> +		double gain;
> >> +	} sensor;
> >>   };
> >>   
> >>   struct IPAContext {
> >> diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
> >> index 59676a70..38917fb7 100644
> >> --- a/src/ipa/rkisp1/rkisp1.cpp
> >> +++ b/src/ipa/rkisp1/rkisp1.cpp
> >> @@ -25,6 +25,7 @@
> >>   
> >>   #include <libcamera/internal/mapped_framebuffer.h>
> >>   
> >> +#include "algorithms/agc.h"
> >>   #include "algorithms/algorithm.h"
> >>   #include "libipa/camera_sensor_helper.h"
> >>   
> >> @@ -34,6 +35,8 @@ namespace libcamera {
> >>   
> >>   LOG_DEFINE_CATEGORY(IPARkISP1)
> >>   
> >> +using namespace std::literals::chrono_literals;
> >> +
> >>   namespace ipa::rkisp1 {
> >>   
> >>   class IPARkISP1 : public IPARkISP1Interface
> >> @@ -66,16 +69,13 @@ private:
> >>   
> >>   	/* Camera sensor controls. */
> >>   	bool autoExposure_;
> >> -	uint32_t exposure_;
> >>   	uint32_t minExposure_;
> >>   	uint32_t maxExposure_;
> >> -	uint32_t gain_;
> >>   	uint32_t minGain_;
> >>   	uint32_t maxGain_;
> >>   
> >>   	/* revision-specific data */
> >>   	rkisp1_cif_isp_version hwRevision_;
> >> -	unsigned int hwAeMeanMax_;
> >>   	unsigned int hwHistBinNMax_;
> >>   	unsigned int hwGammaOutMaxSamples_;
> >>   	unsigned int hwHistogramWeightGridsSize_;
> >> @@ -95,13 +95,11 @@ int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
> >>   	/* \todo Add support for other revisions */
> >>   	switch (hwRevision) {
> >>   	case RKISP1_V10:
> >> -		hwAeMeanMax_ = RKISP1_CIF_ISP_AE_MEAN_MAX_V10;
> >>   		hwHistBinNMax_ = RKISP1_CIF_ISP_HIST_BIN_N_MAX_V10;
> >>   		hwGammaOutMaxSamples_ = RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V10;
> >>   		hwHistogramWeightGridsSize_ = RKISP1_CIF_ISP_HISTOGRAM_WEIGHT_GRIDS_SIZE_V10;
> >>   		break;
> >>   	case RKISP1_V12:
> >> -		hwAeMeanMax_ = RKISP1_CIF_ISP_AE_MEAN_MAX_V12;
> >>   		hwHistBinNMax_ = RKISP1_CIF_ISP_HIST_BIN_N_MAX_V12;
> >>   		hwGammaOutMaxSamples_ = RKISP1_CIF_ISP_GAMMA_OUT_MAX_SAMPLES_V12;
> >>   		hwHistogramWeightGridsSize_ = RKISP1_CIF_ISP_HISTOGRAM_WEIGHT_GRIDS_SIZE_V12;
> >> @@ -126,6 +124,9 @@ int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
> >>   		return -ENODEV;
> >>   	}
> >>   
> >> +	/* Construct our Algorithms */
> >> +	algorithms_.push_back(std::make_unique<algorithms::Agc>());
> >> +
> >>   	return 0;
> >>   }
> >>   
> >> @@ -167,11 +168,9 @@ int IPARkISP1::configure([[maybe_unused]] const IPACameraSensorInfo &info,
> >>   
> >>   	minExposure_ = itExp->second.min().get<int32_t>();
> >>   	maxExposure_ = itExp->second.max().get<int32_t>();
> >> -	exposure_ = minExposure_;
> >>   
> >>   	minGain_ = itGain->second.min().get<int32_t>();
> >>   	maxGain_ = itGain->second.max().get<int32_t>();
> >> -	gain_ = minGain_;
> >>   
> >>   	LOG(IPARkISP1, Info)
> >>   		<< "Exposure: " << minExposure_ << "-" << maxExposure_
> >> @@ -183,6 +182,26 @@ int IPARkISP1::configure([[maybe_unused]] const IPACameraSensorInfo &info,
> >>   	/* Set the hardware revision for the algorithms. */
> >>   	context_.configuration.hw.revision = hwRevision_;
> >>   
> >> +	context_.configuration.sensor.lineDuration = info.lineLength * 1.0s / info.pixelRate;
> >> +
> >> +	/*
> >> +	 * When the AGC computes the new exposure values for a frame, it needs
> >> +	 * to know the limits for shutter speed and analogue gain.
> >> +	 * As it depends on the sensor, update it with the controls.
> >> +	 *
> >> +	 * \todo take VBLANK into account for maximum shutter speed
> >> +	 */
> >> +	context_.configuration.agc.minShutterSpeed = minExposure_ * context_.configuration.sensor.lineDuration;
> >> +	context_.configuration.agc.maxShutterSpeed = maxExposure_ * context_.configuration.sensor.lineDuration;
> >> +	context_.configuration.agc.minAnalogueGain = camHelper_->gain(minGain_);
> >> +	context_.configuration.agc.maxAnalogueGain = camHelper_->gain(maxGain_);
> >> +
> >> +	for (auto const &algo : algorithms_) {
> >> +		int ret = algo->configure(context_, info);
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >> +
> >>   	return 0;
> >>   }
> >>   
> >> @@ -227,6 +246,11 @@ void IPARkISP1::processEvent(const RkISP1Event &event)
> >>   			reinterpret_cast<rkisp1_stat_buffer *>(
> >>   				mappedBuffers_.at(bufferId).planes()[0].data());
> >>   
> >> +		context_.frameContext.sensor.exposure =
> >> +			event.sensorControls.get(V4L2_CID_EXPOSURE).get<int32_t>();
> >> +		context_.frameContext.sensor.gain =
> >> +			camHelper_->gain(event.sensorControls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>());
> >> +
> >>   		updateStatistics(frame, stats);
> >>   		break;
> >>   	}
> >> @@ -271,44 +295,12 @@ void IPARkISP1::queueRequest(unsigned int frame, rkisp1_params_cfg *params,
> >>   void IPARkISP1::updateStatistics(unsigned int frame,
> >>   				 const rkisp1_stat_buffer *stats)
> >>   {
> >> -	const rkisp1_cif_isp_stat *params = &stats->params;
> >>   	unsigned int aeState = 0;
> >>   
> >> -	if (stats->meas_type & RKISP1_CIF_ISP_STAT_AUTOEXP) {
> >> -		const rkisp1_cif_isp_ae_stat *ae = &params->ae;
> >> -
> >> -		const unsigned int target = 60;
> >> -
> >> -		unsigned int value = 0;
> >> -		unsigned int num = 0;
> >> -		for (unsigned int i = 0; i < hwAeMeanMax_; i++) {
> >> -			if (ae->exp_mean[i] <= 15)
> >> -				continue;
> >> -
> >> -			value += ae->exp_mean[i];
> >> -			num++;
> >> -		}
> >> -		value /= num;
> >> +	for (auto const &algo : algorithms_)
> >> +		algo->process(context_, stats);
> >>   
> >> -		double factor = (double)target / value;
> >> -
> >> -		if (frame % 3 == 0) {
> >> -			double exposure;
> >> -
> >> -			exposure = factor * exposure_ * gain_ / minGain_;
> >> -			exposure_ = std::clamp<uint64_t>((uint64_t)exposure,
> >> -							 minExposure_,
> >> -							 maxExposure_);
> >> -
> >> -			exposure = exposure / exposure_ * minGain_;
> >> -			gain_ = std::clamp<uint64_t>((uint64_t)exposure,
> >> -						     minGain_, maxGain_);
> >> -
> >> -			setControls(frame + 1);
> >> -		}
> >> -
> >> -		aeState = fabs(factor - 1.0f) < 0.05f ? 2 : 1;
> >> -	}
> >> +	setControls(frame);
> >>   
> >>   	metadataReady(frame, aeState);
> >>   }
> >> @@ -318,9 +310,12 @@ void IPARkISP1::setControls(unsigned int frame)
> >>   	RkISP1Action op;
> >>   	op.op = ActionV4L2Set;
> >>   
> >> +	uint32_t exposure = context_.frameContext.agc.exposure;
> >> +	uint32_t gain = camHelper_->gainCode(context_.frameContext.agc.gain);
> >> +
> >>   	ControlList ctrls(ctrls_);
> >> -	ctrls.set(V4L2_CID_EXPOSURE, static_cast<int32_t>(exposure_));
> >> -	ctrls.set(V4L2_CID_ANALOGUE_GAIN, static_cast<int32_t>(gain_));
> >> +	ctrls.set(V4L2_CID_EXPOSURE, static_cast<int32_t>(exposure));
> >> +	ctrls.set(V4L2_CID_ANALOGUE_GAIN, static_cast<int32_t>(gain));
> >>   	op.sensorControls = ctrls;
> >>   
> >>   	queueFrameAction.emit(frame, op);

-- 
Regards,

Laurent Pinchart


More information about the libcamera-devel mailing list