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authorUmang Jain <umang.jain@ideasonboard.com>2022-03-31 22:19:13 +0530
committerUmang Jain <umang.jain@ideasonboard.com>2022-04-02 00:34:22 +0530
commit08d7e66df0782bc4aa0d01ca12cbc98c3073c26f (patch)
tree0d1e82788639b790f923224449ef629641ca9c2e /src/ipa/raspberrypi/data
parent0040820fc175a202f12d41f9b18e91e1e540d0df (diff)
ipa: rkisp1: Split queuing of request and parameter filling
Queuing of request (i.e. passing of controls to the IPA) and filling of the parameters buffer are two separate operations. Treat them as such by splitting them into two functions in the rkisp1 IPA interface. Signed-off-by: Umang Jain <umang.jain@ideasonboard.com> Reviewed-by: Paul Elder <paul.elder@ideasonboard.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
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/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * Copyright (C) 2019, Raspberry Pi (Trading) Limited
 *
 * agc.cpp - AGC/AEC control algorithm
 */

#include <map>

#include "linux/bcm2835-isp.h"

#include "libcamera/internal/log.h"

#include "../awb_status.h"
#include "../device_status.h"
#include "../histogram.hpp"
#include "../lux_status.h"
#include "../metadata.hpp"

#include "agc.hpp"

using namespace RPiController;
using namespace libcamera;

LOG_DEFINE_CATEGORY(RPiAgc)

#define NAME "rpi.agc"

#define PIPELINE_BITS 13 // seems to be a 13-bit pipeline

void AgcMeteringMode::Read(boost::property_tree::ptree const &params)
{
	int num = 0;
	for (auto &p : params.get_child("weights")) {
		if (num == AGC_STATS_SIZE)
			throw std::runtime_error("AgcConfig: too many weights");
		weights[num++] = p.second.get_value<double>();
	}
	if (num != AGC_STATS_SIZE)
		throw std::runtime_error("AgcConfig: insufficient weights");
}

static std::string
read_metering_modes(std::map<std::string, AgcMeteringMode> &metering_modes,
		    boost::property_tree::ptree const &params)
{
	std::string first;
	for (auto &p : params) {
		AgcMeteringMode metering_mode;
		metering_mode.Read(p.second);
		metering_modes[p.first] = std::move(metering_mode);
		if (first.empty())
			first = p.first;
	}
	return first;
}

static int read_double_list(std::vector<double> &list,
			    boost::property_tree::ptree const &params)
{
	for (auto &p : params)
		list.push_back(p.second.get_value<double>());
	return list.size();
}

void AgcExposureMode::Read(boost::property_tree::ptree const &params)
{
	int num_shutters =
		read_double_list(shutter, params.get_child("shutter"));
	int num_ags = read_double_list(gain, params.get_child("gain"));
	if (num_shutters < 2 || num_ags < 2)
		throw std::runtime_error(
			"AgcConfig: must have at least two entries in exposure profile");
	if (num_shutters != num_ags)
		throw std::runtime_error(
			"AgcConfig: expect same number of exposure and gain entries in exposure profile");
}

static std::string
read_exposure_modes(std::map<std::string, AgcExposureMode> &exposure_modes,
		    boost::property_tree::ptree const &params)
{
	std::string first;
	for (auto &p : params) {
		AgcExposureMode exposure_mode;
		exposure_mode.Read(p.second);
		exposure_modes[p.first] = std::move(exposure_mode);
		if (first.empty())
			first = p.first;
	}
	return first;
}

void AgcConstraint::Read(boost::property_tree::ptree const &params)
{
	std::string bound_string = params.get<std::string>("bound", "");
	transform(bound_string.begin(), bound_string.end(),
		  bound_string.begin(), ::toupper);
	if (bound_string != "UPPER" && bound_string != "LOWER")
		throw std::runtime_error(
			"AGC constraint type should be UPPER or LOWER");
	bound = bound_string == "UPPER" ? Bound::UPPER : Bound::LOWER;
	q_lo = params.get<double>("q_lo");
	q_hi = params.get<double>("q_hi");
	Y_target.Read(params.get_child("y_target"));
}

static AgcConstraintMode
read_constraint_mode(boost::property_tree::ptree const &params)
{
	AgcConstraintMode mode;
	for (auto &p : params) {
		AgcConstraint constraint;
		constraint.Read(p.second);
		mode.push_back(std::move(constraint));
	}
	return mode;
}

static std::string read_constraint_modes(
	std::map<std::string, AgcConstraintMode> &constraint_modes,
	boost::property_tree::ptree const &params)
{
	std::string first;
	for (auto &p : params) {
		constraint_modes[p.first] = read_constraint_mode(p.second);
		if (first.empty())
			first = p.first;
	}
	return first;
}

void AgcConfig::Read(boost::property_tree::ptree const &params)
{
	LOG(RPiAgc, Debug) << "AgcConfig";
	default_metering_mode = read_metering_modes(
		metering_modes, params.get_child("metering_modes"));
	default_exposure_mode = read_exposure_modes(
		exposure_modes, params.get_child("exposure_modes"));
	default_constraint_mode = read_constraint_modes(
		constraint_modes, params.get_child("constraint_modes"));
	Y_target.Read(params.get_child("y_target"));
	speed = params.get<double>("speed", 0.2);
	startup_frames = params.get<uint16_t>("startup_frames", 10);
	convergence_frames = params.get<unsigned int>("convergence_frames", 6);
	fast_reduce_threshold =
		params.get<double>("fast_reduce_threshold", 0.4);
	base_ev = params.get<double>("base_ev", 1.0);
	// Start with quite a low value as ramping up is easier than ramping down.
	default_exposure_time = params.get<double>("default_exposure_time", 1000);
	default_analogue_gain = params.get<double>("default_analogue_gain", 1.0);
}

Agc::Agc(Controller *controller)
	: AgcAlgorithm(controller), metering_mode_(nullptr),
	  exposure_mode_(nullptr), constraint_mode_(nullptr),
	  frame_count_(0), lock_count_(0),
	  last_target_exposure_(0.0),
	  ev_(1.0), flicker_period_(0.0),
	  max_shutter_(0), fixed_shutter_(0), fixed_analogue_gain_(0.0)
{
	memset(&awb_, 0, sizeof(awb_));
	// Setting status_.total_exposure_value_ to zero initially tells us
	// it's not been calculated yet (i.e. Process hasn't yet run).
	memset(&status_, 0, sizeof(status_));
	status_.ev = ev_;
	memset(&last_device_status_, 0, sizeof(last_device_status_));
}

char const *Agc::Name() const
{
	return NAME;
}

void Agc::Read(boost::property_tree::ptree const &params)
{
	LOG(RPiAgc, Debug) << "Agc";
	config_.Read(params);
	// Set the config's defaults (which are the first ones it read) as our
	// current modes, until someone changes them.  (they're all known to
	// exist at this point)
	metering_mode_name_ = config_.default_metering_mode;
	metering_mode_ = &config_.metering_modes[metering_mode_name_];
	exposure_mode_name_ = config_.default_exposure_mode;
	exposure_mode_ = &config_.exposure_modes[exposure_mode_name_];
	constraint_mode_name_ = config_.default_constraint_mode;
	constraint_mode_ = &config_.constraint_modes[constraint_mode_name_];
	// Set up the "last shutter/gain" values, in case AGC starts "disabled".
	status_.shutter_time = config_.default_exposure_time;
	status_.analogue_gain = config_.default_analogue_gain;
}

bool Agc::IsPaused() const
{
	return false;
}

void Agc::Pause()
{
	fixed_shutter_ = status_.shutter_time;
	fixed_analogue_gain_ = status_.analogue_gain;
}

void Agc::Resume()
{
	fixed_shutter_ = 0;
	fixed_analogue_gain_ = 0;
}

unsigned int Agc::GetConvergenceFrames() const
{
	// If shutter and gain have been explicitly set, there is no
	// convergence to happen, so no need to drop any frames - return zero.
	if (fixed_shutter_ && fixed_analogue_gain_)
		return 0;
	else
		return config_.convergence_frames;
}

void Agc::SetEv(double ev)
{
	ev_ = ev;
}

void Agc::SetFlickerPeriod(double flicker_period)
{
	flicker_period_ = flicker_period;
}

void Agc::SetMaxShutter(double max_shutter)
{
	max_shutter_ = max_shutter;
}

void Agc::SetFixedShutter(double fixed_shutter)
{
	fixed_shutter_ = fixed_shutter;
	// Set this in case someone calls Pause() straight after.
	status_.shutter_time = clipShutter(fixed_shutter_);
}

void Agc::SetFixedAnalogueGain(double fixed_analogue_gain)
{
	fixed_analogue_gain_ = fixed_analogue_gain;
	// Set this in case someone calls Pause() straight after.
	status_.analogue_gain = fixed_analogue_gain;
}

void Agc::SetMeteringMode(std::string const &metering_mode_name)
{
	metering_mode_name_ = metering_mode_name;
}

void Agc::SetExposureMode(std::string const &exposure_mode_name)
{
	exposure_mode_name_ = exposure_mode_name;
}

void Agc::SetConstraintMode(std::string const &constraint_mode_name)
{
	constraint_mode_name_ = constraint_mode_name;
}

void Agc::SwitchMode([[maybe_unused]] CameraMode const &camera_mode,
		     Metadata *metadata)
{
	housekeepConfig();

	double fixed_shutter = clipShutter(fixed_shutter_);
	if (fixed_shutter != 0.0 && fixed_analogue_gain_ != 0.0) {
		// We're going to reset the algorithm here with these fixed values.

		fetchAwbStatus(metadata);
		double min_colour_gain = std::min({ awb_.gain_r, awb_.gain_g, awb_.gain_b, 1.0 });
		ASSERT(min_colour_gain != 0.0);

		// This is the equivalent of computeTargetExposure and applyDigitalGain.
		target_.total_exposure_no_dg = fixed_shutter * fixed_analogue_gain_;
		target_.total_exposure = target_.total_exposure_no_dg / min_colour_gain;

		// Equivalent of filterExposure. This resets any "history".
		filtered_ = target_;

		// Equivalent of divideUpExposure.
		filtered_.shutter = fixed_shutter;
		filtered_.analogue_gain = fixed_analogue_gain_;
	} else if (status_.total_exposure_value) {
		// On a mode switch, it's possible the exposure profile could change,
		// or a fixed exposure/gain might be set so we divide up the exposure/
		// gain again, but we don't change any target values.
		divideUpExposure();
	} else {
		// We come through here on startup, when at least one of the shutter
		// or gain has not been fixed. We must still write those values out so
		// that they will be applied immediately. We supply some arbitrary defaults
		// for any that weren't set.

		// Equivalent of divideUpExposure.
		filtered_.shutter = fixed_shutter ? fixed_shutter : config_.default_exposure_time;
		filtered_.analogue_gain = fixed_analogue_gain_ ? fixed_analogue_gain_ : config_.default_analogue_gain;
	}

	writeAndFinish(metadata, false);
}

void Agc::Prepare(Metadata *image_metadata)
{
	status_.digital_gain = 1.0;
	fetchAwbStatus(image_metadata); // always fetch it so that Process knows it's been done

	if (status_.total_exposure_value) {
		// Process has run, so we have meaningful values.
		DeviceStatus device_status;
		if (image_metadata->Get("device.status", device_status) == 0) {
			double actual_exposure = device_status.shutter_speed *
						 device_status.analogue_gain;
			if (actual_exposure) {
				status_.digital_gain =
					status_.total_exposure_value /
					actual_exposure;
				LOG(RPiAgc, Debug) << "Want total exposure " << status_.total_exposure_value;
				// Never ask for a gain < 1.0, and also impose
				// some upper limit. Make it customisable?
				status_.digital_gain = std::max(
					1.0,
					std::min(status_.digital_gain, 4.0));
				LOG(RPiAgc, Debug) << "Actual exposure " << actual_exposure;
				LOG(RPiAgc, Debug) << "Use digital_gain " << status_.digital_gain;
				LOG(RPiAgc, Debug) << "Effective exposure " << actual_exposure * status_.digital_gain;
				// Decide whether AEC/AGC has converged.
				updateLockStatus(device_status);
			}
		} else
			LOG(RPiAgc, Warning) << Name() << ": no device metadata";
		image_metadata->Set("agc.status", status_);
	}
}

void Agc::Process(StatisticsPtr &stats, Metadata *image_metadata)
{
	frame_count_++;
	// First a little bit of housekeeping, fetching up-to-date settings and
	// configuration, that kind of thing.
	housekeepConfig();
	// Get the current exposure values for the frame that's just arrived.
	fetchCurrentExposure(image_metadata);
	// Compute the total gain we require relative to the current exposure.
	double gain, target_Y;
	computeGain(stats.get(), image_metadata, gain, target_Y);
	// Now compute the target (final) exposure which we think we want.
	computeTargetExposure(gain);
	// Some of the exposure has to be applied as digital gain, so work out
	// what that is. This function also tells us whether it's decided to
	// "desaturate" the image more quickly.
	bool desaturate = applyDigitalGain(gain, target_Y);
	// The results have to be filtered so as not to change too rapidly.
	filterExposure(desaturate);
	// The last thing is to divide up the exposure value into a shutter time
	// and analogue_gain, according to the current exposure mode.
	divideUpExposure();
	// Finally advertise what we've done.
	writeAndFinish(image_metadata, desaturate);
}

void Agc::updateLockStatus(DeviceStatus const &device_status)
{
	const double ERROR_FACTOR = 0.10; // make these customisable?
	const int MAX_LOCK_COUNT = 5;
	// Reset "lock count" when we exceed this multiple of ERROR_FACTOR
	const double RESET_MARGIN = 1.5;

	// Add 200us to the exposure time error to allow for line quantisation.
	double exposure_error = last_device_status_.shutter_speed * ERROR_FACTOR + 200;
	double gain_error = last_device_status_.analogue_gain * ERROR_FACTOR;
	double target_error = last_target_exposure_ * ERROR_FACTOR;

	// Note that we don't know the exposure/gain limits of the sensor, so
	// the values we keep requesting may be unachievable. For this reason
	// we only insist that we're close to values in the past few frames.
	if (device_status.shutter_speed > last_device_status_.shutter_speed - exposure_error &&
	    device_status.shutter_speed < last_device_status_.shutter_speed + exposure_error &&
	    device_status.analogue_gain > last_device_status_.analogue_gain - gain_error &&
	    device_status.analogue_gain < last_device_status_.analogue_gain + gain_error &&
	    status_.target_exposure_value > last_target_exposure_ - target_error &&
	    status_.target_exposure_value < last_target_exposure_ + target_error)
		lock_count_ = std::min(lock_count_ + 1, MAX_LOCK_COUNT);
	else if (device_status.shutter_speed < last_device_status_.shutter_speed - RESET_MARGIN * exposure_error ||
		 device_status.shutter_speed > last_device_status_.shutter_speed + RESET_MARGIN * exposure_error ||
		 device_status.analogue_gain < last_device_status_.analogue_gain - RESET_MARGIN * gain_error ||
		 device_status.analogue_gain > last_device_status_.analogue_gain + RESET_MARGIN * gain_error ||
		 status_.target_exposure_value < last_target_exposure_ - RESET_MARGIN * target_error ||
		 status_.target_exposure_value > last_target_exposure_ + RESET_MARGIN * target_error)
		lock_count_ = 0;

	last_device_status_ = device_status;
	last_target_exposure_ = status_.target_exposure_value;

	LOG(RPiAgc, Debug) << "Lock count updated to " << lock_count_;
	status_.locked = lock_count_ == MAX_LOCK_COUNT;
}

static void copy_string(std::string const &s, char *d, size_t size)
{
	size_t length = s.copy(d, size - 1);
	d[length] = '\0';
}

void Agc::housekeepConfig()
{
	// First fetch all the up-to-date settings, so no one else has to do it.
	status_.ev = ev_;
	status_.fixed_shutter = clipShutter(fixed_shutter_);
	status_.fixed_analogue_gain = fixed_analogue_gain_;
	status_.flicker_period = flicker_period_;
	LOG(RPiAgc, Debug) << "ev " << status_.ev << " fixed_shutter "
			   << status_.fixed_shutter << " fixed_analogue_gain "
			   << status_.fixed_analogue_gain;
	// Make sure the "mode" pointers point to the up-to-date things, if
	// they've changed.
	if (strcmp(metering_mode_name_.c_str(), status_.metering_mode)) {
		auto it = config_.metering_modes.find(metering_mode_name_);
		if (it == config_.metering_modes.end())
			throw std::runtime_error("Agc: no metering mode " +
						 metering_mode_name_);
		metering_mode_ = &it->second;
		copy_string(metering_mode_name_, status_.metering_mode,
			    sizeof(status_.metering_mode));
	}
	if (strcmp(exposure_mode_name_.c_str(), status_.exposure_mode)) {
		auto it = config_.exposure_modes.find(exposure_mode_name_);
		if (it == config_.exposure_modes.end())
			throw std::runtime_error("Agc: no exposure profile " +
						 exposure_mode_name_);
		exposure_mode_ = &it->second;
		copy_string(exposure_mode_name_, status_.exposure_mode,
			    sizeof(status_.exposure_mode));
	}
	if (strcmp(constraint_mode_name_.c_str(), status_.constraint_mode)) {
		auto it =
			config_.constraint_modes.find(constraint_mode_name_);
		if (it == config_.constraint_modes.end())
			throw std::runtime_error("Agc: no constraint list " +
						 constraint_mode_name_);
		constraint_mode_ = &it->second;
		copy_string(constraint_mode_name_, status_.constraint_mode,
			    sizeof(status_.constraint_mode));
	}
	LOG(RPiAgc, Debug) << "exposure_mode "
			   << exposure_mode_name_ << " constraint_mode "
			   << constraint_mode_name_ << " metering_mode "
			   << metering_mode_name_;
}

void Agc::fetchCurrentExposure(Metadata *image_metadata)
{
	std::unique_lock<Metadata> lock(*image_metadata);
	DeviceStatus *device_status =
		image_metadata->GetLocked<DeviceStatus>("device.status");
	if (!device_status)
		throw std::runtime_error("Agc: no device metadata");
	current_.shutter = device_status->shutter_speed;
	current_.analogue_gain = device_status->analogue_gain;
	AgcStatus *agc_status =
		image_metadata->GetLocked<AgcStatus>("agc.status");
	current_.total_exposure = agc_status ? agc_status->total_exposure_value : 0;
	current_.total_exposure_no_dg = current_.shutter * current_.analogue_gain;
}

void Agc::fetchAwbStatus(Metadata *image_metadata)
{
	awb_.gain_r = 1.0; // in case not found in metadata
	awb_.gain_g = 1.0;
	awb_.gain_b = 1.0;
	if (image_metadata->Get("awb.status", awb_) != 0)
		LOG(RPiAgc, Warning) << "Agc: no AWB status found";
}

static double compute_initial_Y(bcm2835_isp_stats *stats, AwbStatus const &awb,
				double weights[], double gain)
{
	bcm2835_isp_stats_region *regions = stats->agc_stats;
	// Note how the calculation below means that equal weights give you
	// "average" metering (i.e. all pixels equally important).
	double R_sum = 0, G_sum = 0, B_sum = 0, pixel_sum = 0;
	for (int i = 0; i < AGC_STATS_SIZE; i++) {
		double counted = regions[i].counted;
		double r_sum = std::min(regions[i].r_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);
		double g_sum = std::min(regions[i].g_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);
		double b_sum = std::min(regions[i].b_sum * gain, ((1 << PIPELINE_BITS) - 1) * counted);
		R_sum += r_sum * weights[i];
		G_sum += g_sum * weights[i];
		B_sum += b_sum * weights[i];
		pixel_sum += counted * weights[i];
	}
	if (pixel_sum == 0.0) {
		LOG(RPiAgc, Warning) << "compute_initial_Y: pixel_sum is zero";
		return 0;
	}
	double Y_sum = R_sum * awb.gain_r * .299 +
		       G_sum * awb.gain_g * .587 +
		       B_sum * awb.gain_b * .114;
	return Y_sum / pixel_sum / (1 << PIPELINE_BITS);
}

// We handle extra gain through EV by adjusting our Y targets. However, you
// simply can't monitor histograms once they get very close to (or beyond!)
// saturation, so we clamp the Y targets to this value. It does mean that EV
// increases don't necessarily do quite what you might expect in certain
// (contrived) cases.

#define EV_GAIN_Y_TARGET_LIMIT 0.9

static double constraint_compute_gain(AgcConstraint &c, Histogram &h,
				      double lux, double ev_gain,
				      double &target_Y)
{
	target_Y = c.Y_target.Eval(c.Y_target.Domain().Clip(lux));
	target_Y = std::min(EV_GAIN_Y_TARGET_LIMIT, target_Y * ev_gain);
	double iqm = h.InterQuantileMean(c.q_lo, c.q_hi);
	return (target_Y * NUM_HISTOGRAM_BINS) / iqm;
}

void Agc::computeGain(bcm2835_isp_stats *statistics, Metadata *image_metadata,
		      double &gain, double &target_Y)
{
	struct LuxStatus lux = {};
	lux.lux = 400; // default lux level to 400 in case no metadata found
	if (image_metadata->Get("lux.status", lux) != 0)
		LOG(RPiAgc, Warning) << "Agc: no lux level found";
	Histogram h(statistics->hist[0].g_hist, NUM_HISTOGRAM_BINS);
	double ev_gain = status_.ev * config_.base_ev;
	// The initial gain and target_Y come from some of the regions. After
	// that we consider the histogram constraints.
	target_Y =
		config_.Y_target.Eval(config_.Y_target.Domain().Clip(lux.lux));
	target_Y = std::min(EV_GAIN_Y_TARGET_LIMIT, target_Y * ev_gain);