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>

1 files changed, 75 insertions, 0 deletions

diff --git a/src/ipa/raspberrypi/controller/rpi/geq.cpp b/src/ipa/raspberrypi/controller/rpi/geq.cpp
new file mode 100644
index 00000000..ee0cb95d
--- /dev/null
+++ b/src/ipa/raspberrypi/controller/rpi/geq.cpp
@@ -0,0 +1,75 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * geq.cpp - GEQ (green equalisation) control algorithm
+ */
+
+#include "../device_status.h"
+#include "../logging.hpp"
+#include "../lux_status.h"
+#include "../pwl.hpp"
+
+#include "geq.hpp"
+
+using namespace RPi;
+
+// We use the lux status so that we can apply stronger settings in darkness (if
+// necessary).
+
+#define NAME "rpi.geq"
+
+Geq::Geq(Controller *controller)
+	: Algorithm(controller)
+{
+}
+
+char const *Geq::Name() const
+{
+	return NAME;
+}
+
+void Geq::Read(boost::property_tree::ptree const &params)
+{
+	config_.offset = params.get<uint16_t>("offset", 0);
+	config_.slope = params.get<double>("slope", 0.0);
+	if (config_.slope < 0.0 || config_.slope >= 1.0)
+		throw std::runtime_error("Geq: bad slope value");
+	if (params.get_child_optional("strength"))
+		config_.strength.Read(params.get_child("strength"));
+}
+
+void Geq::Prepare(Metadata *image_metadata)
+{
+	LuxStatus lux_status = {};
+	lux_status.lux = 400;
+	if (image_metadata->Get("lux.status", lux_status))
+		RPI_WARN("Geq: no lux data found");
+	DeviceStatus device_status = {};
+	device_status.analogue_gain = 1.0; // in case not found
+	if (image_metadata->Get("device.status", device_status))
+		RPI_WARN("Geq: no device metadata - use analogue gain of 1x");
+	GeqStatus geq_status = {};
+	double strength =
+		config_.strength.Empty()
+			? 1.0
+			: config_.strength.Eval(config_.strength.Domain().Clip(
+				  lux_status.lux));
+	strength *= device_status.analogue_gain;
+	double offset = config_.offset * strength;
+	double slope = config_.slope * strength;
+	geq_status.offset = std::min(65535.0, std::max(0.0, offset));
+	geq_status.slope = std::min(.99999, std::max(0.0, slope));
+	RPI_LOG("Geq: offset " << geq_status.offset << " slope "
+			       << geq_status.slope << " (analogue gain "
+			       << device_status.analogue_gain << " lux "
+			       << lux_status.lux << ")");
+	image_metadata->Set("geq.status", geq_status);
+}
+
+// Register algorithm with the system.
+static Algorithm *Create(Controller *controller)
+{
+	return (Algorithm *)new Geq(controller);
+}
+static RegisterAlgorithm reg(NAME, &Create);