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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 ¶ms);
double ctLo; /* low CT value for search */
double ctHi; /* high CT value for search */
};
struct AwbPrior {
void read(boost::property_tree::ptree const ¶ms);
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 ¶ms);
/* 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;
/* clamp on colour error term (so as not to penalise non-grey excessively) */
double deltaLimit;
/* step size control in coarse search */
double coarseStep;
/* how far to wander off CT curve towards "more purple" */
double transversePos;
/* how far to wander off CT curve towards "more green" */
double transverseNeg;
/*
* red sensitivity ratio (set to canonical sensor's R/G divided by this
* sensor's R/G)
*/
double sensitivityR;
/*
* blue sensitivity ratio (set to canonical sensor's B/G divided by this
* sensor's B/G)
*/
double sensitivityB;
/* The whitepoint (which we normally "aim" for) can be moved. */
double whitepointR;
double whitepointB;
bool bayes; /* use Bayesian algorithm */
};
class Awb : public AwbAlgorithm
{
public:
Awb(Controller *controller = NULL);
~Awb();
char const *name() const override;
void initialise() override;
void read(boost::property_tree::ptree const ¶ms) override;
/* AWB handles "pausing" for itself. */
bool isPaused() const override;
void pause() override;
void resume() override;
unsigned int getConvergenceFrames() const override;
void setMode(std::string const &name) override;
void setManualGains(double manualR, double manualB) override;
void switchMode(CameraMode const &cameraMode, Metadata *metadata) override;
void prepare(Metadata *imageMetadata) override;
void process(StatisticsPtr &stats, Metadata *imageMetadata) override;
struct RGB {
RGB(double r = 0, double g = 0, double b = 0)
: R(r), G(g), B(b)
{
}
double R, G, B;
RGB &operator+=(RGB const &other)
{
R += other.R, G += other.G, B += other.B;
return *this;
}
};
private:
bool isAutoEnabled() const;
/* configuration is read-only, and available to both threads */
AwbConfig config_;
std::thread asyncThread_;
void asyncFunc(); /* asynchronous thread function */
std::mutex mutex_;
/* condvar for async thread to wait on */
std::condition_variable asyncSignal_;
/* condvar for synchronous thread to wait on */
std::condition_variable syncSignal_;
/* for sync thread to check if async thread finished (requires mutex) */
bool asyncFinished_;
/* for async thread to check if it's been told to run (requires mutex) */
bool asyncStart_;
/* for async thread to check if it's been told to quit (requires mutex) */
bool asyncAbort_;
/*
* The following are only for the synchronous thread to use:
* for sync thread to note its has asked async thread to run
*/
bool asyncStarted_;
/* counts up to framePeriod before restarting the async thread */
int framePhase_;
int frameCount_; /* counts up to startup_frames */
AwbStatus syncResults_;
AwbStatus prevSyncResults_;
std::string modeName_;
/*
* The following are for the asynchronous thread to use, though the main
* thread can set/reset them if the async thread is known to be idle:
*/
void restartAsync(StatisticsPtr &stats, double lux);
/* copy out the results from the async thread so that it can be restarted */
void fetchAsyncResults();
StatisticsPtr statistics_;
AwbMode *mode_;
double lux_;
AwbStatus asyncResults_;
void doAwb();
void awbBayes();
void awbGrey();
void prepareStats();
double computeDelta2Sum(double gainR, double gainB);
Pwl interpolatePrior();
double coarseSearch(Pwl const &prior);
void fineSearch(double &t, double &r, double &b, Pwl const &prior);
std::vector<RGB> zones_;
std::vector<Pwl::Point> points_;
/* manual r setting */
double manualR_;
/* manual b setting */
double manualB_;
bool firstSwitchMode_; /* is this the first call to SwitchMode? */
};
static inline Awb::RGB operator+(Awb::RGB const &a, Awb::RGB const &b)
{
return Awb::RGB(a.R + b.R, a.G + b.G, a.B + b.B);
}
static inline Awb::RGB operator-(Awb::RGB const &a, Awb::RGB const &b)
{
return Awb::RGB(a.R - b.R, a.G - b.G, a.B - b.B);
}
static inline Awb::RGB operator*(double d, Awb::RGB const &rgb)
{
return Awb::RGB(d * rgb.R, d * rgb.G, d * rgb.B);
}
static inline Awb::RGB operator*(Awb::RGB const &rgb, double d)
{
return d * rgb;
}
} /* namespace RPiController */
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