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-rw-r--r--src/ipa/rkisp1/algorithms/agc.cpp285
-rw-r--r--src/ipa/rkisp1/algorithms/agc.h46
-rw-r--r--src/ipa/rkisp1/algorithms/meson.build1
-rw-r--r--src/ipa/rkisp1/ipa_context.cpp50
-rw-r--r--src/ipa/rkisp1/ipa_context.h22
-rw-r--r--src/ipa/rkisp1/rkisp1.cpp83
6 files changed, 443 insertions, 44 deletions
diff --git a/src/ipa/rkisp1/algorithms/agc.cpp b/src/ipa/rkisp1/algorithms/agc.cpp
new file mode 100644
index 00000000..2c222a4e
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/agc.cpp
@@ -0,0 +1,285 @@
+/* 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.
+ *
+ * \todo Why is the value different between IPU3 and RkISP1 ?
+ */
+static constexpr double kRelativeLuminanceTarget = 0.4;
+
+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 < V12 have RKISP1_CIF_ISP_AE_MEAN_MAX_V10 entries,
+ * - 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;
+
+ /* \todo Use actual frame index by populating it in the frameContext. */
+ frameCount_ = 0;
+ return 0;
+}
+
+/**
+ * \brief Apply a filter on the exposure value to limit the speed of changes
+ * \param[in] exposureValue The target exposure from the AGC algorithm
+ *
+ * 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.
+ *
+ * \return The filtered exposure
+ */
+utils::Duration Agc::filterExposure(utils::Duration exposureValue)
+{
+ double speed = 0.2;
+
+ /* Adapt instantly if we are in startup phase. */
+ if (frameCount_ < kNumStartupFrames)
+ speed = 1.0;
+
+ /*
+ * If we are close to the desired result, go faster to avoid making
+ * multiple micro-adjustments.
+ * \todo Make this customisable?
+ */
+ if (filteredExposure_ < 1.2 * exposureValue &&
+ filteredExposure_ > 0.8 * exposureValue)
+ speed = sqrt(speed);
+
+ filteredExposure_ = speed * exposureValue +
+ filteredExposure_ * (1.0 - speed);
+
+ LOG(RkISP1Agc, Debug) << "After filtering, exposure " << filteredExposure_;
+
+ 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)
+ return;
+
+ /* 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 exposureValue = effectiveExposureValue * yGain;
+
+ /* Clamp the exposure value to the min and max authorized. */
+ utils::Duration maxTotalExposure = maxShutterSpeed * maxAnalogueGain;
+ exposureValue = std::min(exposureValue, maxTotalExposure);
+ LOG(RkISP1Agc, Debug) << "Target total exposure " << exposureValue
+ << ", maximum is " << maxTotalExposure;
+
+ /*
+ * Divide the exposure value as new exposure and gain values.
+ * \todo estimate if we need to desaturate
+ */
+ exposureValue = filterExposure(exposureValue);
+
+ /*
+ * Push the shutter time up to the maximum first, and only then
+ * increase the gain.
+ */
+ 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 to apply to the frame
+ *
+ * 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. In this case, saturating after the conversion to
+ * YUV doesn't take into account the fact that the R, G and B components
+ * contribute differently to the relative luminance.
+ *
+ * \todo Have a dedicated YUV algorithm ?
+ *
+ * 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
+ *
+ * \return The 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 */
+
+ 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
+ *
+ * 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_++;
+}
+
+} /* 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..07b9ea37
--- /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 exposureValue);
+ 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);
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-18 15:00:08 +0000