libcamera: ipa: Raspberry Pi IPA

Initial implementation of the Raspberry Pi (BCM2835) libcamera IPA and
associated libraries.

All code is licensed under the BSD-2-Clause terms.
Copyright (c) 2019-2020 Raspberry Pi Trading Ltd.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/ipa/raspberrypi/controller/rpi/ccm.cpp

@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * ccm.cpp - CCM (colour correction matrix) control algorithm
+ */
+
+#include "../awb_status.h"
+#include "../ccm_status.h"
+#include "../logging.hpp"
+#include "../lux_status.h"
+#include "../metadata.hpp"
+
+#include "ccm.hpp"
+
+using namespace RPi;
+
+// This algorithm selects a CCM (Colour Correction Matrix) according to the
+// colour temperature estimated by AWB (interpolating between known matricies as
+// necessary). Additionally the amount of colour saturation can be controlled
+// both according to the current estimated lux level and according to a
+// saturation setting that is exposed to applications.
+
+#define NAME "rpi.ccm"
+
+Matrix::Matrix()
+{
+	memset(m, 0, sizeof(m));
+}
+Matrix::Matrix(double m0, double m1, double m2, double m3, double m4, double m5,
+	       double m6, double m7, double m8)
+{
+	m[0][0] = m0, m[0][1] = m1, m[0][2] = m2, m[1][0] = m3, m[1][1] = m4,
+	m[1][2] = m5, m[2][0] = m6, m[2][1] = m7, m[2][2] = m8;
+}
+void Matrix::Read(boost::property_tree::ptree const &params)
+{
+	double *ptr = (double *)m;
+	int n = 0;
+	for (auto it = params.begin(); it != params.end(); it++) {
+		if (n++ == 9)
+			throw std::runtime_error("Ccm: too many values in CCM");
+		*ptr++ = it->second.get_value<double>();
+	}
+	if (n < 9)
+		throw std::runtime_error("Ccm: too few values in CCM");
+}
+
+Ccm::Ccm(Controller *controller)
+	: CcmAlgorithm(controller), saturation_(1.0) {}
+
+char const *Ccm::Name() const
+{
+	return NAME;
+}
+
+void Ccm::Read(boost::property_tree::ptree const &params)
+{
+	if (params.get_child_optional("saturation"))
+		config_.saturation.Read(params.get_child("saturation"));
+	for (auto &p : params.get_child("ccms")) {
+		CtCcm ct_ccm;
+		ct_ccm.ct = p.second.get<double>("ct");
+		ct_ccm.ccm.Read(p.second.get_child("ccm"));
+		if (!config_.ccms.empty() &&
+		    ct_ccm.ct <= config_.ccms.back().ct)
+			throw std::runtime_error(
+				"Ccm: CCM not in increasing colour temperature order");
+		config_.ccms.push_back(std::move(ct_ccm));
+	}
+	if (config_.ccms.empty())
+		throw std::runtime_error("Ccm: no CCMs specified");
+}
+
+void Ccm::SetSaturation(double saturation)
+{
+	saturation_ = saturation;
+}
+
+void Ccm::Initialise() {}
+
+template<typename T>
+static bool get_locked(Metadata *metadata, std::string const &tag, T &value)
+{
+	T *ptr = metadata->GetLocked<T>(tag);
+	if (ptr == nullptr)
+		return false;
+	value = *ptr;
+	return true;
+}
+
+Matrix calculate_ccm(std::vector<CtCcm> const &ccms, double ct)
+{
+	if (ct <= ccms.front().ct)
+		return ccms.front().ccm;
+	else if (ct >= ccms.back().ct)
+		return ccms.back().ccm;
+	else {
+		int i = 0;
+		for (; ct > ccms[i].ct; i++)
+			;
+		double lambda =
+			(ct - ccms[i - 1].ct) / (ccms[i].ct - ccms[i - 1].ct);
+		return lambda * ccms[i].ccm + (1.0 - lambda) * ccms[i - 1].ccm;
+	}
+}
+
+Matrix apply_saturation(Matrix const &ccm, double saturation)
+{
+	Matrix RGB2Y(0.299, 0.587, 0.114, -0.169, -0.331, 0.500, 0.500, -0.419,
+		     -0.081);
+	Matrix Y2RGB(1.000, 0.000, 1.402, 1.000, -0.345, -0.714, 1.000, 1.771,
+		     0.000);
+	Matrix S(1, 0, 0, 0, saturation, 0, 0, 0, saturation);
+	return Y2RGB * S * RGB2Y * ccm;
+}
+
+void Ccm::Prepare(Metadata *image_metadata)
+{
+	bool awb_ok = false, lux_ok = false;
+	struct AwbStatus awb = {};
+	awb.temperature_K = 4000; // in case no metadata
+	struct LuxStatus lux = {};
+	lux.lux = 400; // in case no metadata
+	{
+		// grab mutex just once to get everything
+		std::lock_guard<Metadata> lock(*image_metadata);
+		awb_ok = get_locked(image_metadata, "awb.status", awb);
+		lux_ok = get_locked(image_metadata, "lux.status", lux);
+	}
+	if (!awb_ok)
+		RPI_WARN("Ccm: no colour temperature found");
+	if (!lux_ok)
+		RPI_WARN("Ccm: no lux value found");
+	Matrix ccm = calculate_ccm(config_.ccms, awb.temperature_K);
+	double saturation = saturation_;
+	struct CcmStatus ccm_status;
+	ccm_status.saturation = saturation;
+	if (!config_.saturation.Empty())
+		saturation *= config_.saturation.Eval(
+			config_.saturation.Domain().Clip(lux.lux));
+	ccm = apply_saturation(ccm, saturation);
+	for (int j = 0; j < 3; j++)
+		for (int i = 0; i < 3; i++)
+			ccm_status.matrix[j * 3 + i] =
+				std::max(-8.0, std::min(7.9999, ccm.m[j][i]));
+	RPI_LOG("CCM: colour temperature " << awb.temperature_K << "K");
+	RPI_LOG("CCM: " << ccm_status.matrix[0] << " " << ccm_status.matrix[1]
+			<< " " << ccm_status.matrix[2] << "     "
+			<< ccm_status.matrix[3] << " " << ccm_status.matrix[4]
+			<< " " << ccm_status.matrix[5] << "     "
+			<< ccm_status.matrix[6] << " " << ccm_status.matrix[7]
+			<< " " << ccm_status.matrix[8]);
+	image_metadata->Set("ccm.status", ccm_status);
+}
+
+// Register algorithm with the system.
+static Algorithm *Create(Controller *controller)
+{
+	return (Algorithm *)new Ccm(controller);
+	;
+}
+static RegisterAlgorithm reg(NAME, &Create);