src/ipa/raspberrypi/controller/rpi/awb.h


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/* SPDX-License-Identifier: BSD-2-Clause */
/*
 * Copyright (C) 2019, Raspberry Pi Ltd
 *
 * awb.h - AWB control algorithm
 */
#pragma once

#include <mutex>
#include <condition_variable>
#include <thread>

#include "../awb_algorithm.h"
#include "../pwl.h"
#include "../awb_status.h"

namespace RPiController {

/* Control algorithm to perform AWB calculations. */

struct AwbMode {
	void read(boost::property_tree::ptree const &params);
	double ctLo; /* low CT value for search */
	double ctHi; /* high CT value for search */
};

struct AwbPrior {
	void read(boost::property_tree::ptree const &params);
	double lux; /* lux level */
	Pwl prior; /* maps CT to prior log likelihood for this lux level */
};

struct AwbConfig {
	AwbConfig() : defaultMode(nullptr) {}
	void read(boost::property_tree::ptree const &params);
	/* Only repeat the AWB calculation every "this many" frames */
	uint16_t framePeriod;
	/* number of initial frames for which speed taken as 1.0 (maximum) */
	uint16_t startupFrames;
	unsigned int convergenceFrames; /* approx number of frames to converge */
	double speed; /* IIR filter speed applied to algorithm results */
	bool fast; /* "fast" mode uses a 16x16 rather than 32x32 grid */
	Pwl ctR; /* function maps CT to r (= R/G) */
	Pwl ctB; /* function maps CT to b (= B/G) */
	/* table of illuminant priors at different lux levels */
	std::vector<AwbPrior> priors;
	/* AWB "modes" (determines the search range) */
	std::map<std::string, AwbMode> modes;
	AwbMode *defaultMode; /* mode used if no mode selected */
	/*
	 * minimum proportion of pixels counted within AWB region for it to be
	 * "useful"
	 */
	double minPixels;
	/* minimum G value of those pixels, to be regarded a "useful" */
	uint16_t minG;
	/*
	 * number of AWB regions that must be "useful" in order to do the AWB
	 * calculation
	 */
	uint32_t minRegions;