1 files changed, 89 insertions, 0 deletions
diff --git a/src/ipa/rpi/controller/rpi/noise.cpp b/src/ipa/rpi/controller/rpi/noise.cpp
new file mode 100644
index 00000000..bcd8b9ed
--- /dev/null
+++ b/src/ipa/rpi/controller/rpi/noise.cpp
@@ -0,0 +1,89 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi Ltd
+ *
+ * noise.cpp - Noise control algorithm
+ */
+
+#include <math.h>
+
+#include <libcamera/base/log.h>
+
+#include "../device_status.h"
+#include "../noise_status.h"
+
+#include "noise.h"
+
+using namespace RPiController;
+using namespace libcamera;
+
+LOG_DEFINE_CATEGORY(RPiNoise)
+
+#define NAME "rpi.noise"
+
+Noise::Noise(Controller *controller)
+	: Algorithm(controller), modeFactor_(1.0)
+{
+}
+
+char const *Noise::name() const
+{
+	return NAME;
+}
+
+void Noise::switchMode(CameraMode const &cameraMode,
+		       [[maybe_unused]] Metadata *metadata)
+{
+	/*
+	 * For example, we would expect a 2x2 binned mode to have a "noise
+	 * factor" of sqrt(2x2) = 2. (can't be less than one, right?)
+	 */
+	modeFactor_ = std::max(1.0, cameraMode.noiseFactor);
+}
+
+int Noise::read(const libcamera::YamlObject &params)
+{
+	auto value = params["reference_constant"].get<double>();
+	if (!value)
+		return -EINVAL;
+	referenceConstant_ = *value;
+
+	value = params["reference_slope"].get<double>();
+	if (!value)
+		return -EINVAL;
+	referenceSlope_ = *value;
+
+	return 0;
+}
+
+void Noise::prepare(Metadata *imageMetadata)
+{
+	struct DeviceStatus deviceStatus;
+	deviceStatus.analogueGain = 1.0; /* keep compiler calm */
+	if (imageMetadata->get("device.status", deviceStatus) == 0) {
+		/*
+		 * There is a slight question as to exactly how the noise
+		 * profile, specifically the constant part of it, scales. For
+		 * now we assume it all scales the same, and we'll revisit this
+		 * if it proves substantially wrong.  NOTE: we may also want to
+		 * make some adjustments based on the camera mode (such as
+		 * binning), if we knew how to discover it...
+		 */
+		double factor = sqrt(deviceStatus.analogueGain) / modeFactor_;
+		struct NoiseStatus status;
+		status.noiseConstant = referenceConstant_ * factor;
+		status.noiseSlope = referenceSlope_ * factor;
+		imageMetadata->set("noise.status", status);
+		LOG(RPiNoise, Debug)
+			<< "constant " << status.noiseConstant
+			<< " slope " << status.noiseSlope;
+	} else
+		LOG(RPiNoise, Warning) << " no metadata";
+}
+
+/* Register algorithm with the system. */
+static Algorithm *create(Controller *controller)
+{
+	return new Noise(controller);
+}
+static RegisterAlgorithm reg(NAME, &create);