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authorDaniel Semkowicz <dse@thaumatec.com>2023-01-19 09:41:08 +0100
committerJacopo Mondi <jacopo.mondi@ideasonboard.com>2023-09-04 14:08:51 +0200
commit0f6172999dafbf9f80c2b5941bf0487a09b18dd5 (patch)
tree1b3faa6d7ff0e23a1a2d0e7d4137c328a1b6ebc2 /src/ipa
parent6d52f4005069c7759e5a6360069fee3d42235d39 (diff)
ipa: Add class that implements base AF control algorithm
Move the code that was common for IPU3 and RPi AF algorithms to a separate class independent of platform specific code. This way each platform can just implement contrast calculation and run the AF control loop basing on this class. Signed-off-by: Daniel Semkowicz <dse@thaumatec.com>
Diffstat (limited to 'src/ipa')
-rw-r--r--src/ipa/libipa/algorithms/af_hill_climbing.cpp374
-rw-r--r--src/ipa/libipa/algorithms/af_hill_climbing.h102
-rw-r--r--src/ipa/libipa/algorithms/meson.build2
3 files changed, 478 insertions, 0 deletions
diff --git a/src/ipa/libipa/algorithms/af_hill_climbing.cpp b/src/ipa/libipa/algorithms/af_hill_climbing.cpp
new file mode 100644
index 00000000..e2eaf3d4
--- /dev/null
+++ b/src/ipa/libipa/algorithms/af_hill_climbing.cpp
@@ -0,0 +1,374 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Red Hat
+ * Copyright (C) 2022, Ideas On Board
+ * Copyright (C) 2022, Theobroma Systems
+ *
+ * af_hill_climbing.cpp - AF Hill Climbing common algorithm
+ */
+
+#include "af_hill_climbing.h"
+
+#include "libcamera/internal/yaml_parser.h"
+
+/**
+ * \file af_hill_climbing.h
+ * \brief AF Hill Climbing common algorithm
+ */
+
+namespace libcamera::ipa::common::algorithms {
+
+LOG_DEFINE_CATEGORY(Af)
+
+/**
+ * \class AfHillClimbing
+ * \brief The base class implementing hill climbing AF control algorithm
+ * \tparam Module The IPA module type for this class of algorithms
+ *
+ * Control part of auto focus algorithm. It calculates the lens position basing
+ * on contrast measure supplied by the higher level. This way it is independent
+ * from the platform.
+ *
+ * Derived class should call processAutofocus() for each measured contrast value
+ * and set the lens to the calculated position.
+ */
+
+/**
+ * \brief Initialize the Algorithm with tuning data
+ * \param[in] tuningData The tuning data for the algorithm
+ *
+ * This function should be called in the init() function of the derived class.
+ * See alse: libcamera::ipa::Algorithm::init()
+ *
+ * \return 0 if successful, an error code otherwise
+ */
+int AfHillClimbing::initBase(const YamlObject &tuningData)
+{
+ minVcmPosition_ = tuningData["min-vcm-position"].get<uint32_t>(0);
+ maxVcmPosition_ = tuningData["max-vcm-position"].get<uint32_t>(100);
+ coarseSearchStep_ = tuningData["coarse-search-step"].get<uint32_t>(30);
+ fineSearchStep_ = tuningData["fine-search-step"].get<uint32_t>(1);
+ fineRange_ = tuningData["fine-scan-range"].get<double>(0.05);
+ maxChange_ = tuningData["max-variance-change"].get<double>(0.5);
+
+ LOG(Af, Debug) << "minVcmPosition_: " << minVcmPosition_
+ << ", maxVcmPosition_: " << maxVcmPosition_
+ << ", coarseSearchStep_: " << coarseSearchStep_
+ << ", fineSearchStep_: " << fineSearchStep_
+ << ", fineRange_: " << fineRange_
+ << ", maxChange_: " << maxChange_;
+
+ return 0;
+}
+
+/**
+ * \brief Provide control values to the algorithm
+ * \param[in] frame The frame number to apply the control values
+ * \param[in] controls The list of user controls
+ *
+ * This function should be called in the queueRequest() function of the derived class.
+ * See alse: libcamera::ipa::Algorithm::queueRequest()
+ */
+void AfHillClimbing::queueRequestBase([[maybe_unused]] const uint32_t frame, const ControlList &controls)
+{
+ for (auto const &[id, value] : controls) {
+ switch (id) {
+ case controls::AF_MODE: {
+ setMode(static_cast<controls::AfModeEnum>(value.get<int32_t>()));
+ break;
+ }
+ case controls::AF_TRIGGER: {
+ setTrigger(static_cast<controls::AfTriggerEnum>(value.get<int32_t>()));
+ break;
+ }
+ case controls::AF_PAUSE: {
+ setPause(static_cast<controls::AfPauseEnum>(value.get<int32_t>()));
+ break;
+ }
+ case controls::LENS_POSITION: {
+ setLensPosition(value.get<float>());
+ break;
+ }
+ default:
+ break;
+ }
+ }
+}
+
+/**
+ * \brief Run the auto focus algorithm loop
+ * \param[in] currentContrast New value of contrast measured for current frame
+ *
+ * This method should be called for each new contrast value that was measured,
+ * usually in the process() method.
+ *
+ * \return New lens position calculated by AF algorithm
+ */
+uint32_t AfHillClimbing::processAutofocus(double currentContrast)
+{
+ currentContrast_ = currentContrast;
+
+ if (shouldSkipFrame())
+ return lensPosition_;
+
+ switch (mode_) {
+ case controls::AfModeManual:
+ /* Nothing to process. */
+ break;
+ case controls::AfModeAuto:
+ processAutoMode();
+ break;
+ case controls::AfModeContinuous:
+ processContinousMode();
+ break;
+ default:
+ break;
+ }
+
+ return lensPosition_;
+}
+
+void AfHillClimbing::processAutoMode()
+{
+ if (state_ == controls::AfStateScanning) {
+ afCoarseScan();
+ afFineScan();
+ }
+}
+
+void AfHillClimbing::processContinousMode()
+{
+ /* If we are in a paused state, we won't process the stats */
+ if (pauseState_ == controls::AfPauseStatePaused)
+ return;
+
+ if (state_ == controls::AfStateScanning) {
+ afCoarseScan();
+ afFineScan();
+ return;
+ }
+
+ /* We can re-start the scan at any moment in AfModeContinuous */
+ if (afIsOutOfFocus()) {
+ afReset();
+ }
+}
+
+/**
+ * \brief Request AF to skip n frames
+ * \param[in] n Number of frames to be skipped
+ *
+ * Requested number of frames will not be used for AF calculation.
+ */
+void AfHillClimbing::setFramesToSkip(uint32_t n)
+{
+ if (n > framesToSkip_)
+ framesToSkip_ = n;
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setMode
+ */
+void AfHillClimbing::setMode(controls::AfModeEnum mode)
+{
+ if (mode == mode_)
+ return;
+
+ LOG(Af, Debug) << "Switched AF mode from " << mode_ << " to " << mode;
+ mode_ = mode;
+
+ state_ = controls::AfStateIdle;
+ pauseState_ = controls::AfPauseStateRunning;
+
+ if (mode_ == controls::AfModeContinuous)
+ afReset();
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setRange
+ */
+void AfHillClimbing::setRange([[maybe_unused]] controls::AfRangeEnum range)
+{
+ LOG(Af, Error) << __FUNCTION__ << " not implemented!";
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setSpeed
+ */
+void AfHillClimbing::setSpeed([[maybe_unused]] controls::AfSpeedEnum speed)
+{
+ LOG(Af, Error) << __FUNCTION__ << " not implemented!";
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setTrigger
+ */
+void AfHillClimbing::setTrigger(controls::AfTriggerEnum trigger)
+{
+ if (mode_ != controls::AfModeAuto) {
+ LOG(Af, Warning) << __FUNCTION__ << " not possible in mode " << mode_;
+ return;
+ }
+
+ LOG(Af, Debug) << "Trigger called with " << trigger;
+
+ if (trigger == controls::AfTriggerStart)
+ afReset();
+ else
+ state_ = controls::AfStateIdle;
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setPause
+ */
+void AfHillClimbing::setPause(controls::AfPauseEnum pause)
+{
+ if (mode_ != controls::AfModeContinuous) {
+ LOG(Af, Warning) << __FUNCTION__ << " not possible in mode " << mode_;
+ return;
+ }
+
+ switch (pause) {
+ case controls::AfPauseImmediate:
+ pauseState_ = controls::AfPauseStatePaused;
+ break;
+ case controls::AfPauseDeferred:
+ /* \todo: add the AfPauseDeferred mode */
+ LOG(Af, Warning) << "AfPauseDeferred is not supported!";
+ break;
+ case controls::AfPauseResume:
+ pauseState_ = controls::AfPauseStateRunning;
+ break;
+ default:
+ break;
+ }
+}
+
+/**
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setLensPosition
+ */
+void AfHillClimbing::setLensPosition(float lensPosition)
+{
+ if (mode_ != controls::AfModeManual) {
+ LOG(Af, Warning) << __FUNCTION__ << " not possible in mode " << mode_;
+ return;
+ }
+
+ lensPosition_ = static_cast<uint32_t>(lensPosition);
+
+ LOG(Af, Debug) << "Requesting lens position " << lensPosition_;
+}
+
+/**
+ * \fn AfHillClimbing::setMeteringMode()
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setMeteringMode
+ */
+
+/**
+ * \fn AfHillClimbing::setWindows()
+ * \copydoc libcamera::ipa::common::algorithms::AfInterface::setWindows
+ */
+
+void AfHillClimbing::afCoarseScan()
+{
+ if (coarseCompleted_)
+ return;
+
+ if (afScan(coarseSearchStep_)) {
+ coarseCompleted_ = true;
+ maxContrast_ = 0;
+ lensPosition_ = lensPosition_ - (lensPosition_ * fineRange_);
+ previousContrast_ = 0;
+ maxStep_ = std::clamp(lensPosition_ + static_cast<uint32_t>((lensPosition_ * fineRange_)),
+ 0U, maxVcmPosition_);
+ }
+}
+
+void AfHillClimbing::afFineScan()
+{
+ if (!coarseCompleted_)
+ return;
+
+ if (afScan(fineSearchStep_)) {
+ LOG(Af, Debug) << "AF found the best focus position!";
+ state_ = controls::AfStateFocused;
+ fineCompleted_ = true;
+ }
+}
+
+bool AfHillClimbing::afScan(uint32_t minSteps)
+{
+ if (lensPosition_ + minSteps > maxStep_) {
+ /* If the max step is reached, move lens to the position. */
+ lensPosition_ = bestPosition_;
+ return true;
+ } else {
+ /*
+ * Find the maximum of the variance by estimating its
+ * derivative. If the direction changes, it means we have passed
+ * a maximum one step before.
+ */
+ if ((currentContrast_ - maxContrast_) >= -(maxContrast_ * 0.1)) {
+ /*
+ * Positive and zero derivative:
+ * The variance is still increasing. The focus could be
+ * increased for the next comparison. Also, the max
+ * variance and previous focus value are updated.
+ */
+ bestPosition_ = lensPosition_;
+ lensPosition_ += minSteps;
+ maxContrast_ = currentContrast_;
+ } else {
+ /*
+ * Negative derivative:
+ * The variance starts to decrease which means the maximum
+ * variance is found. Set focus step to previous good one
+ * then return immediately.
+ */
+ lensPosition_ = bestPosition_;
+ return true;
+ }
+ }
+
+ previousContrast_ = currentContrast_;
+ LOG(Af, Debug) << "Previous step is " << bestPosition_
+ << ", Current step is " << lensPosition_;
+ return false;
+}
+
+void AfHillClimbing::afReset()
+{
+ LOG(Af, Debug) << "Reset AF parameters";
+ lensPosition_ = minVcmPosition_;
+ maxStep_ = maxVcmPosition_;
+ state_ = controls::AfStateScanning;
+ previousContrast_ = 0.0;
+ coarseCompleted_ = false;
+ fineCompleted_ = false;
+ maxContrast_ = 0.0;
+ setFramesToSkip(1);
+}
+
+bool AfHillClimbing::afIsOutOfFocus()
+{
+ const uint32_t diff_var = std::abs(currentContrast_ - maxContrast_);
+ const double var_ratio = diff_var / maxContrast_;
+ LOG(Af, Debug) << "Variance change rate: " << var_ratio
+ << ", Current VCM step: " << lensPosition_;
+ if (var_ratio > maxChange_)
+ return true;
+ else
+ return false;
+}
+
+bool AfHillClimbing::shouldSkipFrame()
+{
+ if (framesToSkip_ > 0) {
+ framesToSkip_--;
+ return true;
+ }
+
+ return false;
+}
+
+} /* namespace libcamera::ipa::common::algorithms */
diff --git a/src/ipa/libipa/algorithms/af_hill_climbing.h b/src/ipa/libipa/algorithms/af_hill_climbing.h
new file mode 100644
index 00000000..6ce95884
--- /dev/null
+++ b/src/ipa/libipa/algorithms/af_hill_climbing.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Red Hat
+ * Copyright (C) 2022, Ideas On Board
+ * Copyright (C) 2022, Theobroma Systems
+ *
+ * af_hill_climbing.h - AF Hill Climbing common algorithm
+ */
+
+#pragma once
+
+#include <libcamera/base/log.h>
+
+#include "af_interface.h"
+
+namespace libcamera {
+
+class YamlObject;
+
+namespace ipa::common::algorithms {
+
+LOG_DECLARE_CATEGORY(Af)
+
+class AfHillClimbing : public AfInterface
+{
+public:
+ AfHillClimbing() = default;
+ virtual ~AfHillClimbing() {}
+
+ controls::AfStateEnum getState() final { return state_; }
+ controls::AfPauseStateEnum getPauseState() final { return pauseState_; }
+
+ /* These methods should be implemented by the derived class: */
+ virtual void setMeteringMode(controls::AfMeteringEnum metering) = 0;
+ virtual void setWindows(Span<const Rectangle> windows) = 0;
+
+protected:
+ int initBase(const YamlObject &tuningData);
+ void queueRequestBase(const uint32_t frame, const ControlList &controls);
+ uint32_t processAutofocus(double currentContrast);
+ void setFramesToSkip(uint32_t n);
+
+private:
+ void setMode(controls::AfModeEnum mode) final;
+ void setRange(controls::AfRangeEnum range) final;
+ void setSpeed(controls::AfSpeedEnum speed) final;
+ void setTrigger(controls::AfTriggerEnum trigger) final;
+ void setPause(controls::AfPauseEnum pause) final;
+ void setLensPosition(float lensPosition) final;
+
+ void processAutoMode();
+ void processContinousMode();
+ void afCoarseScan();
+ void afFineScan();
+ bool afScan(uint32_t minSteps);
+ void afReset();
+ bool afIsOutOfFocus();
+ bool shouldSkipFrame();
+
+ controls::AfModeEnum mode_ = controls::AfModeManual;
+ controls::AfStateEnum state_ = controls::AfStateIdle;
+ controls::AfPauseStateEnum pauseState_ = controls::AfPauseStateRunning;
+
+ /* VCM step configuration. It is the current setting of the VCM step. */
+ uint32_t lensPosition_ = 0;
+ /* The best VCM step. It is a local optimum VCM step during scanning. */
+ uint32_t bestPosition_ = 0;
+
+ /* Current AF statistic contrast. */
+ double currentContrast_ = 0;
+ /* It is used to determine the derivative during scanning */
+ double previousContrast_ = 0;
+ double maxContrast_ = 0;
+ /* The designated maximum range of focus scanning. */
+ uint32_t maxStep_ = 0;
+ /* If the coarse scan completes, it is set to true. */
+ bool coarseCompleted_ = false;
+ /* If the fine scan completes, it is set to true. */
+ bool fineCompleted_ = false;
+
+ uint32_t framesToSkip_ = 0;
+
+ /*
+ * Focus steps range of the VCM control
+ * \todo should be obtained from the VCM driver
+ */
+ uint32_t minVcmPosition_;
+ uint32_t maxVcmPosition_;
+
+ /* Minimum focus step for searching appropriate focus */
+ uint32_t coarseSearchStep_;
+ uint32_t fineSearchStep_;
+
+ /* Fine scan range 0 < fineRange_ < 1 */
+ double fineRange_;
+
+ /* Max ratio of variance change, 0.0 < maxChange_ < 1.0 */
+ double maxChange_;
+};
+
+} /* namespace ipa::common::algorithms */
+} /* namespace libcamera */
diff --git a/src/ipa/libipa/algorithms/meson.build b/src/ipa/libipa/algorithms/meson.build
index 0a1f18fa..a8d94056 100644
--- a/src/ipa/libipa/algorithms/meson.build
+++ b/src/ipa/libipa/algorithms/meson.build
@@ -2,8 +2,10 @@
common_ipa_algorithms_headers = files([
'af_interface.h',
+ 'af_hill_climbing.h',
])
common_ipa_algorithms_sources = files([
'af_interface.cpp',
+ 'af_hill_climbing.cpp',
])