[libcamera-devel,v1,4/6] ipa: rkisp1: Introduce AWB

14998 diff mbox series

diff --git a/src/ipa/rkisp1/algorithms/awb.cpp b/src/ipa/rkisp1/algorithms/awb.cpp
new file mode 100644
index 000000000..0ec94764a
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/awb.cpp
@@ -0,0 +1,149 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Ideas On Board
+ *
+ * awb.cpp - AWB control algorithm
+ */
+
+#include "awb.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include <libcamera/base/log.h>
+
+#include <libcamera/ipa/core_ipa_interface.h>
+
+/**
+ * \file awb.h
+ */
+
+namespace libcamera {
+
+namespace ipa::rkisp1::algorithms {
+
+/**
+ * \class Awb
+ * \brief A Grey world white balance correction algorithm
+ */
+
+LOG_DEFINE_CATEGORY(RkISP1Awb)
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::configure
+ */
+int Awb::configure(IPAContext &context,
+		   const IPACameraSensorInfo &configInfo)
+{
+	context.frameContext.awb.gains.red = 1.0;
+	context.frameContext.awb.gains.blue = 1.0;
+	context.frameContext.awb.gains.green = 1.0;
+
+	/* Define the measurement window for AGC. */
+	context.configuration.awb.measureWindow.h_offs = configInfo.outputSize.width / 8;
+	context.configuration.awb.measureWindow.v_offs = configInfo.outputSize.height / 8;
+	context.configuration.awb.measureWindow.h_size = 3 * configInfo.outputSize.width / 4;
+	context.configuration.awb.measureWindow.v_size = 3 * configInfo.outputSize.height / 4;
+
+	return 0;
+}
+
+uint32_t Awb::estimateCCT(double red, double green, double blue)
+{
+	/* Convert the RGB values to CIE tristimulus values (XYZ) */
+	double X = (-0.14282) * (red) + (1.54924) * (green) + (-0.95641) * (blue);
+	double Y = (-0.32466) * (red) + (1.57837) * (green) + (-0.73191) * (blue);
+	double Z = (-0.68202) * (red) + (0.77073) * (green) + (0.56332) * (blue);
+
+	/* Calculate the normalized chromaticity values */
+	double x = X / (X + Y + Z);
+	double y = Y / (X + Y + Z);
+
+	/* Calculate CCT */
+	double n = (x - 0.3320) / (0.1858 - y);
+	return 449 * n * n * n + 3525 * n * n + 6823.3 * n + 5520.33;
+}
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::process
+ */
+void Awb::process([[maybe_unused]] IPAContext &context, const rkisp1_stat_buffer *stats)
+{
+	const rkisp1_cif_isp_stat *params = &stats->params;
+	const rkisp1_cif_isp_awb_stat *awb = &params->awb;
+
+	/* Get the YCbCr mean values */
+	double yMean = awb->awb_mean[0].mean_y_or_g;
+	double crMean = awb->awb_mean[0].mean_cr_or_r;
+	double cbMean = awb->awb_mean[0].mean_cb_or_b;
+
+	/* Convert from YCbCr to RGB. */
+	double redMean = yMean + 1.402 * (crMean - 128);
+	double blueMean = yMean + 1.772 * (cbMean - 128);
+	double greenMean = yMean - 0.34414 * (cbMean - 128) - 0.71414 * (crMean - 128);
+
+	/* Estimate the red and blue gains to apply in a grey world. */
+	double redGain = greenMean / (redMean + 1);
+	double blueGain = greenMean / (blueMean + 1);
+
+	/* Filter the values to avoid oscillations. */
+	IPAFrameContext &frameContext = context.frameContext;
+
+	frameContext.awb.temperatureK = estimateCCT(redMean, greenMean, blueMean);
+	frameContext.awb.gains.red = 0.2 * redGain +
+				     0.8 * frameContext.awb.gains.red;
+	frameContext.awb.gains.blue = 0.2 * blueGain +
+				      0.8 * frameContext.awb.gains.blue;
+	/* Hardcode the green gain to 1.0. */
+	frameContext.awb.gains.green = 1.0;
+
+	LOG(RkISP1Awb, Debug) << "Gain found for red: " << context.frameContext.awb.gains.red
+			      << " and for blue: " << context.frameContext.awb.gains.blue;
+}
+
+/**
+ * \copydoc libcamera::ipa::Algorithm::prepare
+ */
+void Awb::prepare([[maybe_unused]] IPAContext &context,
+		  rkisp1_params_cfg *params)
+{
+	params->others.awb_gain_config.gain_green_b = 256 * context.frameContext.awb.gains.green;
+	params->others.awb_gain_config.gain_blue = 256 * context.frameContext.awb.gains.blue;
+	params->others.awb_gain_config.gain_red = 256 * context.frameContext.awb.gains.red;
+	params->others.awb_gain_config.gain_green_r = 256 * context.frameContext.awb.gains.green;
+
+	/* Configure the gains to apply. */
+	params->module_en_update |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
+	/* Update the ISP to apply the gains configured. */
+	params->module_ens |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
+	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_AWB_GAIN;
+
+	/* Configure the measure window for AWB. */
+	params->meas.awb_meas_config.awb_wnd = context.configuration.awb.measureWindow;
+	/*
+	 * Measure Y, Cr and Cb means.
+	 * \todo RGB is not working, the kernel seems to not configure it ?
+	 */
+	params->meas.awb_meas_config.awb_mode = RKISP1_CIF_ISP_AWB_MODE_YCBCR;
+	/* Reference Cr and Cb. */
+	params->meas.awb_meas_config.awb_ref_cb = 128;
+	params->meas.awb_meas_config.awb_ref_cr = 128;
+	/* Y values to include are between min_y and max_y only. */
+	params->meas.awb_meas_config.min_y = 16;
+	params->meas.awb_meas_config.max_y = 250;
+	/* Maximum Cr+Cb value to take into account for awb. */
+	params->meas.awb_meas_config.max_csum = 250;
+	/* Minimum Cr and Cb values to take into account. */
+	params->meas.awb_meas_config.min_c = 16;
+	/* Number of frames to use to estimate the mean (0 means 1 frame). */
+	params->meas.awb_meas_config.frames = 0;
+	/* Update AWB measurement unit configuration. */
+	params->module_cfg_update |= RKISP1_CIF_ISP_MODULE_AWB;
+	/* Make sure the ISP is measuring the means for the next frame. */
+	params->module_en_update |= RKISP1_CIF_ISP_MODULE_AWB;
+	params->module_ens |= RKISP1_CIF_ISP_MODULE_AWB;
+}
+
+} /* namespace ipa::rkisp1::algorithms */
+
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/awb.h b/src/ipa/rkisp1/algorithms/awb.h
new file mode 100644
index 000000000..0a9fb82c1
--- /dev/null
+++ b/src/ipa/rkisp1/algorithms/awb.h
@@ -0,0 +1,33 @@ 
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2021, Ideas On Board
+ *
+ * awb.h - AWB control algorithm
+ */
+
+#pragma once
+
+#include <linux/rkisp1-config.h>
+
+#include "algorithm.h"
+
+namespace libcamera {
+
+namespace ipa::rkisp1::algorithms {
+
+class Awb : public Algorithm
+{
+public:
+	Awb() = default;
+	~Awb() = default;
+
+	int configure(IPAContext &context, const IPACameraSensorInfo &configInfo) override;
+	void prepare(IPAContext &context, rkisp1_params_cfg *params) override;
+	void process(IPAContext &context, const rkisp1_stat_buffer *stats) override;
+
+private:
+	uint32_t estimateCCT(double red, double green, double blue);
+};
+
+} /* namespace ipa::rkisp1::algorithms */
+} /* namespace libcamera */
diff --git a/src/ipa/rkisp1/algorithms/meson.build b/src/ipa/rkisp1/algorithms/meson.build
index e6767aa5f..faec0eb3e 100644
--- a/src/ipa/rkisp1/algorithms/meson.build
+++ b/src/ipa/rkisp1/algorithms/meson.build
@@ -2,6 +2,7 @@ 
 
 rkisp1_ipa_algorithms = files([
     'agc.cpp',
+    'awb.cpp',
     'blc.cpp',
     'sdg.cpp',
 ])
diff --git a/src/ipa/rkisp1/ipa_context.cpp b/src/ipa/rkisp1/ipa_context.cpp
index 992c92256..2f53eb2f6 100644
--- a/src/ipa/rkisp1/ipa_context.cpp
+++ b/src/ipa/rkisp1/ipa_context.cpp
@@ -78,6 +78,14 @@  namespace libcamera::ipa::rkisp1 {
  * \brief Hardware revision of the ISP
  */
 
+/**
+ * \var IPASessionConfiguration::awb
+ * \brief AWB parameters configuration of the IPA
+ *
+ * \var IPASessionConfiguration::awb.measureWindow
+ * \brief AWB measure window
+ */
+
 /**
  * \var IPASessionConfiguration::sensor
  * \brief Sensor-specific configuration of the IPA
@@ -102,6 +110,26 @@  namespace libcamera::ipa::rkisp1 {
  * The gain should be adapted to the sensor specific gain code before applying.
  */
 
+/**
+ * \var IPAFrameContext::awb
+ * \brief Context for the Automatic White Balance algorithm
+ *
+ * \struct IPAFrameContext::awb.gains
+ * \brief White balance gains
+ *
+ * \var IPAFrameContext::awb.gains.red
+ * \brief White balance gain for R channel
+ *
+ * \var IPAFrameContext::awb.gains.green
+ * \brief White balance gain for G channel
+ *
+ * \var IPAFrameContext::awb.gains.blue
+ * \brief White balance gain for B channel
+ *
+ * \var IPAFrameContext::awb.temperatureK
+ * \brief Estimated color temperature
+ */
+
 /**
  * \var IPAFrameContext::sensor
  * \brief Effective sensor values
diff --git a/src/ipa/rkisp1/ipa_context.h b/src/ipa/rkisp1/ipa_context.h
index c447369f3..51eae8b61 100644
--- a/src/ipa/rkisp1/ipa_context.h
+++ b/src/ipa/rkisp1/ipa_context.h
@@ -12,6 +12,8 @@ 
 
 #include <libcamera/base/utils.h>
 
+#include <libcamera/geometry.h>
+
 namespace libcamera {
 
 namespace ipa::rkisp1 {
@@ -22,8 +24,13 @@  struct IPASessionConfiguration {
 		utils::Duration maxShutterSpeed;
 		double minAnalogueGain;
 		double maxAnalogueGain;
+		struct rkisp1_cif_isp_window measureWindow;
 	} agc;
 
+	struct {
+		struct rkisp1_cif_isp_window measureWindow;
+	} awb;
+
 	struct {
 		utils::Duration lineDuration;
 	} sensor;
@@ -39,6 +46,16 @@  struct IPAFrameContext {
 		double gain;
 	} agc;
 
+	struct {
+		struct {
+			double red;
+			double green;
+			double blue;
+		} gains;
+
+		double temperatureK;
+	} awb;
+
 	struct {
 		uint32_t exposure;
 		double gain;
diff --git a/src/ipa/rkisp1/rkisp1.cpp b/src/ipa/rkisp1/rkisp1.cpp
index ec879ba37..979f28420 100644
--- a/src/ipa/rkisp1/rkisp1.cpp
+++ b/src/ipa/rkisp1/rkisp1.cpp
@@ -27,6 +27,7 @@ 
 
 #include "algorithms/agc.h"
 #include "algorithms/algorithm.h"
+#include "algorithms/awb.h"
 #include "algorithms/blc.h"
 #include "algorithms/sdg.h"
 #include "libipa/camera_sensor_helper.h"
@@ -127,6 +128,7 @@  int IPARkISP1::init(const IPASettings &settings, unsigned int hwRevision)
 
 	/* Construct our Algorithms */
 	algorithms_.push_back(std::make_unique<algorithms::Agc>());
+	algorithms_.push_back(std::make_unique<algorithms::Awb>());
 	algorithms_.push_back(std::make_unique<algorithms::BlackLevelCorrection>());
 	algorithms_.push_back(std::make_unique<algorithms::SensorDeGamma>());