[PATCH v4 09/18] libcamera: ipa: add Soft IPA

Hans de Goede hdegoede at redhat.com
Thu Feb 29 19:36:20 CET 2024


From: Andrey Konovalov <andrey.konovalov at linaro.org>

Define the Soft IPA main and event interfaces, add the Soft IPA
implementation.

The current src/ipa/meson.build assumes the IPA name to match the
pipeline name. For this reason "-Dipas=simple" is used for the
Soft IPA module.

Auto exposure/gain and AWB implementation by Dennis, Toon and Martti.

Auto exposure/gain targets a Mean Sample Value of 2.5 following
the MSV calculation algorithm from:
https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf

Tested-by: Bryan O'Donoghue <bryan.odonoghue at linaro.org> # sc8280xp Lenovo x13s
Tested-by: Pavel Machek <pavel at ucw.cz>
Reviewed-by: Pavel Machek <pavel at ucw.cz>
Signed-off-by: Andrey Konovalov <andrey.konovalov at linaro.org>
Co-developed-by: Dennis Bonke <admin at dennisbonke.com>
Signed-off-by: Dennis Bonke <admin at dennisbonke.com>
Co-developed-by: Marttico <g.martti at gmail.com>
Signed-off-by: Marttico <g.martti at gmail.com>
Co-developed-by: Toon Langendam <t.langendam at gmail.com>
Signed-off-by: Toon Langendam <t.langendam at gmail.com>
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
Changes in v4:
- Use int32_t for again*_ and exposure*_ as this matches
  the value the corresponding ControlValue::get() returns
- Check for mmap() returning MAP_FAILED on error
- Drop std::move() called on const SharedFD & argument
- Replace #defines (EXPOSURE_OPTIMAL_VALUE etc) with const expressions
- Use std::clamp() to keep exposure_ and again_ between the *_min_ and
  the *_max_
- add comment on non-linear gain value vs gain code

Changes in v3:
- Use new SwIspStats::kYHistogramSize constexpr and adjust
  the auto-exposure/-gain code so that it can deal with
  that having a different value then 16 (modify the loop
  to divide the histogram in 5 bins to not have hardcoded
  values)
- Rename a few foo_bar symbols to fooBar
---
 Documentation/Doxyfile.in         |   1 +
 include/libcamera/ipa/meson.build |   1 +
 include/libcamera/ipa/soft.mojom  |  28 +++
 meson_options.txt                 |   2 +-
 src/ipa/simple/data/meson.build   |   9 +
 src/ipa/simple/data/soft.conf     |   3 +
 src/ipa/simple/meson.build        |  25 +++
 src/ipa/simple/soft_simple.cpp    | 326 ++++++++++++++++++++++++++++++
 8 files changed, 394 insertions(+), 1 deletion(-)
 create mode 100644 include/libcamera/ipa/soft.mojom
 create mode 100644 src/ipa/simple/data/meson.build
 create mode 100644 src/ipa/simple/data/soft.conf
 create mode 100644 src/ipa/simple/meson.build
 create mode 100644 src/ipa/simple/soft_simple.cpp

diff --git a/Documentation/Doxyfile.in b/Documentation/Doxyfile.in
index a86ea6c1..2be8d47b 100644
--- a/Documentation/Doxyfile.in
+++ b/Documentation/Doxyfile.in
@@ -44,6 +44,7 @@ EXCLUDE                = @TOP_SRCDIR@/include/libcamera/base/span.h \
                          @TOP_SRCDIR@/src/libcamera/pipeline/ \
                          @TOP_SRCDIR@/src/libcamera/tracepoints.cpp \
                          @TOP_BUILDDIR@/include/libcamera/internal/tracepoints.h \
+                         @TOP_BUILDDIR@/include/libcamera/ipa/soft_ipa_interface.h \
                          @TOP_BUILDDIR@/src/libcamera/proxy/
 
 EXCLUDE_PATTERNS       = @TOP_BUILDDIR@/include/libcamera/ipa/*_serializer.h \
diff --git a/include/libcamera/ipa/meson.build b/include/libcamera/ipa/meson.build
index f3b4881c..3352d08f 100644
--- a/include/libcamera/ipa/meson.build
+++ b/include/libcamera/ipa/meson.build
@@ -65,6 +65,7 @@ pipeline_ipa_mojom_mapping = {
     'ipu3': 'ipu3.mojom',
     'rkisp1': 'rkisp1.mojom',
     'rpi/vc4': 'raspberrypi.mojom',
+    'simple': 'soft.mojom',
     'vimc': 'vimc.mojom',
 }
 
diff --git a/include/libcamera/ipa/soft.mojom b/include/libcamera/ipa/soft.mojom
new file mode 100644
index 00000000..c249bd75
--- /dev/null
+++ b/include/libcamera/ipa/soft.mojom
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+/*
+ * \todo Document the interface and remove the related EXCLUDE_PATTERNS entry.
+ */
+
+module ipa.soft;
+
+import "include/libcamera/ipa/core.mojom";
+
+interface IPASoftInterface {
+	init(libcamera.IPASettings settings,
+	     libcamera.SharedFD fdStats,
+	     libcamera.SharedFD fdParams,
+	     libcamera.ControlInfoMap sensorCtrlInfoMap)
+		=> (int32 ret);
+	start() => (int32 ret);
+	stop();
+	configure(libcamera.ControlInfoMap sensorCtrlInfoMap)
+		=> (int32 ret);
+
+	[async] processStats(libcamera.ControlList sensorControls);
+};
+
+interface IPASoftEventInterface {
+	setSensorControls(libcamera.ControlList sensorControls);
+	setIspParams(int32 dummy);
+};
diff --git a/meson_options.txt b/meson_options.txt
index 99dab96d..2644bef0 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -27,7 +27,7 @@ option('gstreamer',
 
 option('ipas',
         type : 'array',
-        choices : ['ipu3', 'rkisp1', 'rpi/vc4', 'vimc'],
+        choices : ['ipu3', 'rkisp1', 'rpi/vc4', 'simple', 'vimc'],
         description : 'Select which IPA modules to build')
 
 option('lc-compliance',
diff --git a/src/ipa/simple/data/meson.build b/src/ipa/simple/data/meson.build
new file mode 100644
index 00000000..33548cc6
--- /dev/null
+++ b/src/ipa/simple/data/meson.build
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: CC0-1.0
+
+conf_files = files([
+    'soft.conf',
+])
+
+install_data(conf_files,
+             install_dir : ipa_data_dir / 'soft',
+             install_tag : 'runtime')
diff --git a/src/ipa/simple/data/soft.conf b/src/ipa/simple/data/soft.conf
new file mode 100644
index 00000000..0c70e7c0
--- /dev/null
+++ b/src/ipa/simple/data/soft.conf
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Dummy configuration file for the soft IPA.
diff --git a/src/ipa/simple/meson.build b/src/ipa/simple/meson.build
new file mode 100644
index 00000000..3e863db7
--- /dev/null
+++ b/src/ipa/simple/meson.build
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: CC0-1.0
+
+ipa_name = 'ipa_soft_simple'
+
+mod = shared_module(ipa_name,
+                    ['soft_simple.cpp', libcamera_generated_ipa_headers],
+                    name_prefix : '',
+                    include_directories : [ipa_includes, libipa_includes],
+                    dependencies : libcamera_private,
+                    link_with : libipa,
+                    install : true,
+                    install_dir : ipa_install_dir)
+
+if ipa_sign_module
+    custom_target(ipa_name + '.so.sign',
+                  input : mod,
+                  output : ipa_name + '.so.sign',
+                  command : [ipa_sign, ipa_priv_key, '@INPUT@', '@OUTPUT@'],
+                  install : false,
+                  build_by_default : true)
+endif
+
+subdir('data')
+
+ipa_names += ipa_name
diff --git a/src/ipa/simple/soft_simple.cpp b/src/ipa/simple/soft_simple.cpp
new file mode 100644
index 00000000..312df4ba
--- /dev/null
+++ b/src/ipa/simple/soft_simple.cpp
@@ -0,0 +1,326 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2023, Linaro Ltd
+ *
+ * soft_simple.cpp - Simple Software Image Processing Algorithm module
+ */
+
+#include <sys/mman.h>
+
+#include <libcamera/base/file.h>
+#include <libcamera/base/log.h>
+#include <libcamera/base/shared_fd.h>
+
+#include <libcamera/control_ids.h>
+#include <libcamera/controls.h>
+
+#include <libcamera/ipa/ipa_interface.h>
+#include <libcamera/ipa/ipa_module_info.h>
+#include <libcamera/ipa/soft_ipa_interface.h>
+
+#include "libcamera/internal/camera_sensor.h"
+#include "libcamera/internal/software_isp/debayer_params.h"
+#include "libcamera/internal/software_isp/swisp_stats.h"
+
+namespace libcamera {
+
+LOG_DEFINE_CATEGORY(IPASoft)
+
+namespace ipa::soft {
+
+class IPASoftSimple : public ipa::soft::IPASoftInterface
+{
+public:
+	IPASoftSimple()
+		: params_(static_cast<DebayerParams *>(MAP_FAILED)),
+		  stats_(static_cast<SwIspStats *>(MAP_FAILED)), ignore_updates_(0)
+	{
+	}
+
+	~IPASoftSimple()
+	{
+		if (stats_ != MAP_FAILED)
+			munmap(stats_, sizeof(SwIspStats));
+		if (params_ != MAP_FAILED)
+			munmap(params_, sizeof(DebayerParams));
+	}
+
+	int init(const IPASettings &settings,
+		 const SharedFD &fdStats,
+		 const SharedFD &fdParams,
+		 const ControlInfoMap &sensorInfoMap) override;
+	int configure(const ControlInfoMap &sensorInfoMap) override;
+
+	int start() override;
+	void stop() override;
+
+	void processStats(const ControlList &sensorControls) override;
+
+private:
+	void updateExposure(double exposureMSV);
+
+	SharedFD fdStats_;
+	SharedFD fdParams_;
+	DebayerParams *params_;
+	SwIspStats *stats_;
+
+	int32_t exposure_min_, exposure_max_;
+	int32_t again_min_, again_max_;
+	int32_t again_, exposure_;
+	unsigned int ignore_updates_;
+};
+
+int IPASoftSimple::init([[maybe_unused]] const IPASettings &settings,
+			const SharedFD &fdStats,
+			const SharedFD &fdParams,
+			const ControlInfoMap &sensorInfoMap)
+{
+	fdStats_ = fdStats;
+	if (!fdStats_.isValid()) {
+		LOG(IPASoft, Error) << "Invalid Statistics handle";
+		return -ENODEV;
+	}
+
+	fdParams_ = fdParams;
+	if (!fdParams_.isValid()) {
+		LOG(IPASoft, Error) << "Invalid Parameters handle";
+		return -ENODEV;
+	}
+
+	params_ = static_cast<DebayerParams *>(mmap(nullptr, sizeof(DebayerParams),
+						    PROT_WRITE, MAP_SHARED,
+						    fdParams_.get(), 0));
+	if (params_ == MAP_FAILED) {
+		LOG(IPASoft, Error) << "Unable to map Parameters";
+		return -errno;
+	}
+
+	stats_ = static_cast<SwIspStats *>(mmap(nullptr, sizeof(SwIspStats),
+						PROT_READ, MAP_SHARED,
+						fdStats_.get(), 0));
+	if (stats_ == MAP_FAILED) {
+		LOG(IPASoft, Error) << "Unable to map Statistics";
+		return -errno;
+	}
+
+	if (sensorInfoMap.find(V4L2_CID_EXPOSURE) == sensorInfoMap.end()) {
+		LOG(IPASoft, Error) << "Don't have exposure control";
+		return -EINVAL;
+	}
+
+	if (sensorInfoMap.find(V4L2_CID_ANALOGUE_GAIN) == sensorInfoMap.end()) {
+		LOG(IPASoft, Error) << "Don't have gain control";
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int IPASoftSimple::configure(const ControlInfoMap &sensorInfoMap)
+{
+	const ControlInfo &exposure_info = sensorInfoMap.find(V4L2_CID_EXPOSURE)->second;
+	const ControlInfo &gain_info = sensorInfoMap.find(V4L2_CID_ANALOGUE_GAIN)->second;
+
+	exposure_min_ = exposure_info.min().get<int32_t>();
+	exposure_max_ = exposure_info.max().get<int32_t>();
+	if (!exposure_min_) {
+		LOG(IPASoft, Warning) << "Minimum exposure is zero, that can't be linear";
+		exposure_min_ = 1;
+	}
+
+	again_min_ = gain_info.min().get<int32_t>();
+	again_max_ = gain_info.max().get<int32_t>();
+	/*
+	 * The camera sensor gain (g) is usually not equal to the value written
+	 * into the gain register (x). But the way how the AGC algorithm changes
+	 * the gain value to make the total exposure closer to the optimum assumes
+	 * that g(x) is not too far from linear function. If the minimal gain is 0,
+	 * the g(x) is likely to be far from the linear, like g(x) = a / (b * x + c).
+	 * To avoid unexpected changes to the gain by the AGC algorithm (abrupt near
+	 * one edge, and very small near the other) we limit the range of the gain
+	 * values used.
+	 */
+	if (!again_min_) {
+		LOG(IPASoft, Warning) << "Minimum gain is zero, that can't be linear";
+		again_min_ = std::min(100, again_min_ / 2 + again_max_ / 2);
+	}
+
+	LOG(IPASoft, Info) << "Exposure " << exposure_min_ << "-" << exposure_max_
+			   << ", gain " << again_min_ << "-" << again_max_;
+
+	return 0;
+}
+
+int IPASoftSimple::start()
+{
+	return 0;
+}
+
+void IPASoftSimple::stop()
+{
+}
+
+/*
+ * The number of bins to use for the optimal exposure calculations.
+ */
+static constexpr unsigned int kExposureBinsCount = 5;
+/*
+ * The exposure is optimal when the mean sample value of the histogram is
+ * in the middle of the range.
+ */
+static constexpr float kExposureOptimal = kExposureBinsCount / 2.0;
+/*
+ * The below value implements the hysteresis for the exposure adjustment.
+ * It is small enough to have the exposure close to the optimal, and is big
+ * enough to prevent the exposure from wobbling around the optimal value.
+ */
+static constexpr float kExposureSatisfactory = 0.2;
+
+void IPASoftSimple::processStats(const ControlList &sensorControls)
+{
+	/*
+	 * Calculate red and blue gains for AWB.
+	 * Clamp max gain at 4.0, this also avoids 0 division.
+	 */
+	if (stats_->sumR_ <= stats_->sumG_ / 4)
+		params_->gainR = 1024;
+	else
+		params_->gainR = 256 * stats_->sumG_ / stats_->sumR_;
+
+	if (stats_->sumB_ <= stats_->sumG_ / 4)
+		params_->gainB = 1024;
+	else
+		params_->gainB = 256 * stats_->sumG_ / stats_->sumB_;
+
+	/* Green gain and gamma values are fixed */
+	params_->gainG = 256;
+	params_->gamma = 0.5;
+
+	setIspParams.emit(0);
+
+	/*
+	 * AE / AGC, use 2 frames delay to make sure that the exposure and
+	 * the gain set have applied to the camera sensor.
+	 */
+	if (ignore_updates_ > 0) {
+		--ignore_updates_;
+		return;
+	}
+
+	/*
+	 * Calculate Mean Sample Value (MSV) according to formula from:
+	 * https://www.araa.asn.au/acra/acra2007/papers/paper84final.pdf
+	 */
+	constexpr unsigned int yHistValsPerBin =
+		SwIspStats::kYHistogramSize / kExposureBinsCount;
+	constexpr unsigned int yHistValsPerBinMod =
+		SwIspStats::kYHistogramSize /
+		(SwIspStats::kYHistogramSize % kExposureBinsCount + 1);
+	int ExposureBins[kExposureBinsCount] = {};
+	unsigned int denom = 0;
+	unsigned int num = 0;
+
+	for (unsigned int i = 0; i < SwIspStats::kYHistogramSize; i++) {
+		unsigned int idx = (i - (i / yHistValsPerBinMod)) / yHistValsPerBin;
+		ExposureBins[idx] += stats_->yHistogram[i];
+	}
+
+	for (unsigned int i = 0; i < kExposureBinsCount; i++) {
+		LOG(IPASoft, Debug) << i << ": " << ExposureBins[i];
+		denom += ExposureBins[i];
+		num += ExposureBins[i] * (i + 1);
+	}
+
+	float exposureMSV = (float)num / denom;
+
+	/* sanity check */
+	if (!sensorControls.contains(V4L2_CID_EXPOSURE) ||
+	    !sensorControls.contains(V4L2_CID_ANALOGUE_GAIN)) {
+		LOG(IPASoft, Error) << "Control(s) missing";
+		return;
+	}
+
+	ControlList ctrls(sensorControls);
+
+	exposure_ = ctrls.get(V4L2_CID_EXPOSURE).get<int32_t>();
+	again_ = ctrls.get(V4L2_CID_ANALOGUE_GAIN).get<int32_t>();
+
+	updateExposure(exposureMSV);
+
+	ctrls.set(V4L2_CID_EXPOSURE, exposure_);
+	ctrls.set(V4L2_CID_ANALOGUE_GAIN, again_);
+
+	ignore_updates_ = 2;
+
+	setSensorControls.emit(ctrls);
+
+	LOG(IPASoft, Debug) << "exposureMSV " << exposureMSV
+			    << " exp " << exposure_ << " again " << again_
+			    << " gain R/B " << params_->gainR << "/" << params_->gainB;
+}
+
+void IPASoftSimple::updateExposure(double exposureMSV)
+{
+	/* DENOMINATOR of 10 gives ~10% increment/decrement; DENOMINATOR of 5 - about ~20% */
+	static constexpr uint8_t kExpDenominator = 10;
+	static constexpr uint8_t kExpNumeratorUp = kExpDenominator + 1;
+	static constexpr uint8_t kExpNumeratorDown = kExpDenominator - 1;
+
+	int next;
+
+	if (exposureMSV < kExposureOptimal - kExposureSatisfactory) {
+		next = exposure_ * kExpNumeratorUp / kExpDenominator;
+		if (next - exposure_ < 1)
+			exposure_ += 1;
+		else
+			exposure_ = next;
+		if (exposure_ >= exposure_max_) {
+			next = again_ * kExpNumeratorUp / kExpDenominator;
+			if (next - again_ < 1)
+				again_ += 1;
+			else
+				again_ = next;
+		}
+	}
+
+	if (exposureMSV > kExposureOptimal + kExposureSatisfactory) {
+		if (exposure_ == exposure_max_ && again_ != again_min_) {
+			next = again_ * kExpNumeratorDown / kExpDenominator;
+			if (again_ - next < 1)
+				again_ -= 1;
+			else
+				again_ = next;
+		} else {
+			next = exposure_ * kExpNumeratorDown / kExpDenominator;
+			if (exposure_ - next < 1)
+				exposure_ -= 1;
+			else
+				exposure_ = next;
+		}
+	}
+
+	exposure_ = std::clamp(exposure_, exposure_min_, exposure_max_);
+	again_ = std::clamp(again_, again_min_, again_max_);
+}
+
+} /* namespace ipa::soft */
+
+/*
+ * External IPA module interface
+ */
+extern "C" {
+const struct IPAModuleInfo ipaModuleInfo = {
+	IPA_MODULE_API_VERSION,
+	0,
+	"SimplePipelineHandler",
+	"simple",
+};
+
+IPAInterface *ipaCreate()
+{
+	return new ipa::soft::IPASoftSimple();
+}
+
+} /* extern "C" */
+
+} /* namespace libcamera */
-- 
2.43.0



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