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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019, Raspberry Pi (Trading) Limited
*
* lux.cpp - Lux control algorithm
*/
#include <math.h>
#include "linux/bcm2835-isp.h"
#include "../device_status.h"
#include "../logging.hpp"
#include "lux.hpp"
using namespace RPi;
#define NAME "rpi.lux"
Lux::Lux(Controller *controller)
: Algorithm(controller)
{
// Put in some defaults as there will be no meaningful values until
// Process has run.
status_.aperture = 1.0;
status_.lux = 400;
}
char const *Lux::Name() const
{
return NAME;
}
void Lux::Read(boost::property_tree::ptree const ¶ms)
{
RPI_LOG(Name());
reference_shutter_speed_ =
params.get<double>("reference_shutter_speed");
reference_gain_ = params.get<double>("reference_gain");
reference_aperture_ = params.get<double>("reference_aperture", 1.0);
reference_Y_ = params.get<double>("reference_Y");
reference_lux_ = params.get<double>("reference_lux");
current_aperture_ = reference_aperture_;
}
void Lux::Prepare(Metadata *image_metadata)
{
std::unique_lock<std::mutex> lock(mutex_);
image_metadata->Set("lux.status", status_);
}
void Lux::Process(StatisticsPtr &stats, Metadata *image_metadata)
{
// set some initial values to shut the compiler up
DeviceStatus device_status =
{ .shutter_speed = 1.0,
.analogue_gain = 1.0,
.lens_position = 0.0,
.aperture = 0.0,
.flash_intensity = 0.0 };
if (image_metadata->Get("device.status", device_status) == 0) {
double current_gain = device_status.analogue_gain;
double current_shutter_speed = device_status.shutter_speed;
double current_aperture = device_status.aperture;
if (current_aperture == 0)
current_aperture = current_aperture_;
uint64_t sum = 0;
uint32_t num = 0;
uint32_t *bin = stats->hist[0].g_hist;
const int num_bins = sizeof(stats->hist[0].g_hist) /
sizeof(stats->hist[0].g_hist[0]);
for (int i = 0; i < num_bins; i++)
sum += bin[i] * (uint64_t)i, num += bin[i];
// add .5 to reflect the mid-points of bins
double current_Y = sum / (double)num + .5;
double gain_ratio = reference_gain_ / current_gain;
double shutter_speed_ratio =
reference_shutter_speed_ / current_shutter_speed;
double aperture_ratio = reference_aperture_ / current_aperture;
double Y_ratio = current_Y * (65536 / num_bins) / reference_Y_;
double estimated_lux = shutter_speed_ratio * gain_ratio *
aperture_ratio * aperture_ratio *
Y_ratio * reference_lux_;
LuxStatus status;
status.lux = estimated_lux;
status.aperture = current_aperture;
RPI_LOG(Name() << ": estimated lux " << estimated_lux);
{
std::unique_lock<std::mutex> lock(mutex_);
status_ = status;
}
// Overwrite the metadata here as well, so that downstream
// algorithms get the latest value.
image_metadata->Set("lux.status", status);
} else
RPI_WARN(Name() << ": no device metadata");
}
// Register algorithm with the system.
static Algorithm *Create(Controller *controller)
{
return (Algorithm *)new Lux(controller);
}
static RegisterAlgorithm reg(NAME, &Create);
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