libcamera: Adding LensShadingCorrection maps and ToneCurve to controls metadata

Having the LensShadingCorrection maps and ToneCurves available in frame
metadata allows creating a DNG file with all necessary information so that the
DNG matches the JPEG image without colour casts.

I opened a PR in raspberrypi/rpicam-apps
(raspberrypi/rpicam-apps#928) improving the colour
accuracy of said DNG files created by these apps. The information needed is
currently not provided by libcamera in the frame metadata.

This patch intends to add LensShadingCorrection maps and ToneCurve to the
controls metadata in libcamera, so that DNG files can be written with correct
colours.

Signed-off-by: Michael Kunz <mkunz@articimaging.eu>

Author: Michael Kunz

src/ipa/rpi/common/ipa_base.cpp

@@ -12,21 +12,25 @@
 
 #include <libcamera/base/log.h>
 #include <libcamera/base/span.h>
+
 #include <libcamera/control_ids.h>
 #include <libcamera/property_ids.h>
 
 #include "controller/af_algorithm.h"
 #include "controller/af_status.h"
 #include "controller/agc_algorithm.h"
+#include "controller/alsc_status.h"
 #include "controller/awb_algorithm.h"
 #include "controller/awb_status.h"
 #include "controller/black_level_status.h"
 #include "controller/ccm_algorithm.h"
 #include "controller/ccm_status.h"
 #include "controller/contrast_algorithm.h"
+#include "controller/contrast_status.h"
 #include "controller/denoise_algorithm.h"
 #include "controller/hdr_algorithm.h"
 #include "controller/lux_status.h"
+#include "controller/noise_status.h"
 #include "controller/sharpen_algorithm.h"
 #include "controller/statistics.h"
 #include "controller/sync_algorithm.h"
@@ -82,6 +86,7 @@ const ControlInfoMap::Map ipaControls{
 		      static_cast<int64_t>(defaultMaxFrameDuration.get<std::micro>()),
 		      Span<const int64_t, 2>{ { static_cast<int64_t>(defaultMinFrameDuration.get<std::micro>()),
 						static_cast<int64_t>(defaultMinFrameDuration.get<std::micro>()) } }) },
+	{ &controls::EnableLensShadingCorrectionMapOutput, ControlInfo(false, true, false) },
 	{ &controls::draft::NoiseReductionMode, ControlInfo(controls::draft::NoiseReductionModeValues) },
 	{ &controls::rpi::StatsOutputEnable, ControlInfo(false, true, false) },
 	{ &controls::rpi::CnnEnableInputTensor, ControlInfo(false, true, false) },
@@ -129,7 +134,7 @@ LOG_DEFINE_CATEGORY(IPARPI)
 namespace ipa::RPi {
 
 IpaBase::IpaBase()
-	: controller_(), frameLengths_(FrameLengthsQueueSize, 0s), statsMetadataOutput_(false),
+	: controller_(), frameLengths_(FrameLengthsQueueSize, 0s), lscMapsOutput_(false), statsMetadataOutput_(false),
 	  stitchSwapBuffers_(false), frameCount_(0), mistrustCount_(0), lastRunTimestamp_(0),
 	  firstStart_(true), flickerState_({ 0, 0s }), cnnEnableInputTensor_(false), awbEnabled_(true)
 {
@@ -245,7 +250,6 @@ int32_t IpaBase::configure(const IPACameraSensorInfo &sensorInfo, const ConfigPa
 		agcStatus.exposureTime = defaultExposureTime;
 		agcStatus.analogueGain = defaultAnalogueGain;
 		applyAGC(&agcStatus, ctrls);
-
 	}
 
 	result->sensorControls = std::move(ctrls);
@@ -795,8 +799,8 @@ static const std::map<int32_t, std::string> HdrModeTable = {
 
 void IpaBase::applyControls(const ControlList &controls)
 {
-	using RPiController::AgcAlgorithm;
 	using RPiController::AfAlgorithm;
+	using RPiController::AgcAlgorithm;
 	using RPiController::ContrastAlgorithm;
 	using RPiController::DenoiseAlgorithm;
 	using RPiController::HdrAlgorithm;
@@ -1478,6 +1482,10 @@ void IpaBase::applyControls(const ControlList &controls)
 			break;
 		}
 
+		case controls::ENABLE_LENS_SHADING_CORRECTION_MAP_OUTPUT:
+			lscMapsOutput_ = ctrl.second.get<bool>();
+			break;
+
 		case controls::rpi::STATS_OUTPUT_ENABLE:
 			statsMetadataOutput_ = ctrl.second.get<bool>();
 			break;
@@ -1762,6 +1770,43 @@ void IpaBase::reportMetadata(unsigned int ipaContext)
 					 static_cast<int32_t>(kpiInfo->dspRuntime) });
 	}
 
+	NoiseStatus *noiseStatus = rpiMetadata.getLocked<NoiseStatus>("noise.status");
+	if (noiseStatus) {
+		float noiseProfile[] = { static_cast<float>(noiseStatus->noiseSlope),
+					 static_cast<float>(noiseStatus->noiseConstant) };
+
+		libcameraMetadata_.set(controls::NoiseProfile, noiseProfile);
+	}
+
+	ContrastStatus *contrastStatus = rpiMetadata.getLocked<ContrastStatus>("contrast.status");
+	if (contrastStatus && contrastStatus->gammaCurve.size() > 0) {
+		std::vector<float> contrast;
+		contrast.reserve(contrastStatus->gammaCurve.size() * 2);
+
+		contrastStatus->gammaCurve.map([&](double x, double y) {
+			contrast.emplace_back(static_cast<float>(x));
+			contrast.emplace_back(static_cast<float>(y));
+		});
+		libcameraMetadata_.set(controls::ToneCurve, contrast);
+	}
+
+	if (lscMapsOutput_) {
+		AlscStatus *alscStatus = rpiMetadata.getLocked<AlscStatus>("alsc.status");
+		if (alscStatus) {
+			uint32_t elements = alscStatus->cols * alscStatus->rows;
+			std::vector<float> map(3 * elements);
+
+			std::copy(alscStatus->r.begin(), alscStatus->r.end(), map.begin() + 0 * elements);
+			std::copy(alscStatus->g.begin(), alscStatus->g.end(), map.begin() + 1 * elements);
+			std::copy(alscStatus->b.begin(), alscStatus->b.end(), map.begin() + 2 * elements);
+
+			uint32_t sizeTable[] = { 3, alscStatus->cols, alscStatus->rows };
+			libcameraMetadata_.set(controls::LensShadingCorrectionMaps, map);
+			libcameraMetadata_.set(controls::LensShadingCorrectionMapSize, sizeTable);
+			libcameraMetadata_.set(controls::EnableLensShadingCorrectionMapOutput, true);
+		}
+	}
+
 	metadataReady.emit(libcameraMetadata_);
 }
 

src/ipa/rpi/common/ipa_base.h

@@ -68,6 +68,7 @@ class IpaBase : public IPARPiInterface
 	std::deque<utils::Duration> frameLengths_;
 	utils::Duration lastTimeout_;
 	ControlList libcameraMetadata_;
+	bool lscMapsOutput_;
 	bool statsMetadataOutput_;
 
 	/* Remember the HDR status after a mode switch. */

src/ipa/rpi/common/meson.build

@@ -5,7 +5,7 @@ rpi_ipa_common_sources = files([
 ])
 
 rpi_ipa_common_includes = [
-    include_directories('..'),
+    include_directories('..','../..'),
 ]
 
 rpi_ipa_common_deps = [

src/ipa/rpi/controller/rpi/alsc.cpp

@@ -409,6 +409,9 @@ void Alsc::prepare(Metadata *imageMetadata)
 	status.r = prevSyncResults_[0].data();
 	status.g = prevSyncResults_[1].data();
 	status.b = prevSyncResults_[2].data();
+	status.cols = config_.tableSize.width;
+	status.rows = config_.tableSize.height;
+
 	imageMetadata->set("alsc.status", status);
 	/*
 	 * Put the results in the global metadata as well. This will be used by

src/libcamera/control_ids_core.yaml

@@ -1374,4 +1374,42 @@ controls:
         The nominal range is [-180, 180], where 0° leaves hues unchanged and the
         range wraps around continuously, with 180° == -180°.
 
+  - EnableLensShadingCorrectionMapOutput:
+      type: bool
+      direction: inout
+      description: |
+        Indicates if the lens shading correction maps should be set in frame-
+        metadata for each frame. Returns true if tables are successfully set.
+
+  - LensShadingCorrectionMaps:
+      type: float
+      direction: out
+      description: |
+        A map giving the lens shading correction factors. Dimesnions of the
+        returned table is [number of channels, sizeX, sizeY] (planar tables)
+      size: [n]
+
+  - LensShadingCorrectionMapSize:
+      type: uint32_t
+      direction: out
+      description: |
+        The number of channels/maps and the size of the lens shading correction
+        maps in pixels. E.g. [3, 32, 32]
+      size: [3]
+
+  - ToneCurve:
+      type: float
+      direction: out
+      description: |
+        A profile tone curve to apply on linear RGB - as it seems it has the sRGB
+        gamma curve baked in.
+      size: [n]
+
+  - NoiseProfile:
+      type: float
+      direction: out
+      description: |
+        The noise profile [Scale, Offset].
+      size: [2]
+
 ...