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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* Copyright (C) 2019, Raspberry Pi (Trading) Limited
*
* awb.hpp - AWB control algorithm
*/
#pragma once
#include <mutex>
#include <condition_variable>
#include <thread>
#include "../awb_algorithm.hpp"
#include "../pwl.hpp"
#include "../awb_status.h"
namespace RPiController {
// Control algorithm to perform AWB calculations.
struct AwbMode {
void Read(boost::property_tree::ptree const ¶ms);
double ct_lo; // low CT value for search
double ct_hi; // 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() : default_mode(nullptr) {}
void Read(boost::property_tree::ptree const ¶ms);
// Only repeat the AWB calculation every "this many" frames
uint16_t frame_period;
// number of initial frames for which speed taken as 1.0 (maximum)
uint16_t startup_frames;
unsigned int convergence_frames; // 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 ct_r; // function maps CT to r (= R/G)
Pwl ct_b; // 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 *default_mode; // mode used if no mode selected
// minimum proportion of pixels counted within AWB region for it to be
// "useful"
double min_pixels;
// minimum G value of those pixels, to be regarded a "useful"
uint16_t min_G;
// number of AWB regions that must be "useful" in order to do the AWB
// calculation
uint32_t min_regions;
// clamp on colour error term (so as not to penalise non-grey excessively)
double delta_limit;
// step size control in coarse search
double coarse_step;
// how far to wander off CT curve towards "more purple"
double transverse_pos;
// how far to wander off CT curve towards "more green"
double transverse_neg;
// red sensitivity ratio (set to canonical sensor's R/G divided by this
// sensor's R/G)
double sensitivity_r;
// blue sensitivity ratio (set to canonical sensor's B/G divided by this
// sensor's B/G)
double sensitivity_b;
// The whitepoint (which we normally "aim" for) can be moved.
double whitepoint_r;
double whitepoint_b;
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;
unsigned int GetConvergenceFrames() const override;
void SetMode(std::string const &name) override;
void SetManualGains(double manual_r, double manual_b) override;
void SwitchMode(CameraMode const &camera_mode, Metadata *metadata) override;
void Prepare(Metadata *image_metadata) override;
void Process(StatisticsPtr &stats, Metadata *image_metadata) override;
struct RGB {
RGB(double _R = INVALID, double _G = INVALID,
double _B = INVALID)
: R(_R), G(_G), B(_B)
{
}
double R, G, B;
static const double INVALID;
bool Valid() const { return G != INVALID; }
bool Invalid() const { return G == INVALID; }
RGB &operator+=(RGB const &other)
{
R += other.R, G += other.G, B += other.B;
return *this;
}
RGB Square() const { return RGB(R * R, G * G, B * B); }
};
private:
// configuration is read-only, and available to both threads
AwbConfig config_;
std::thread async_thread_;
void asyncFunc(); // asynchronous thread function
std::mutex mutex_;
// condvar for async thread to wait on
std::condition_variable async_signal_;
// condvar for synchronous thread to wait on
std::condition_variable sync_signal_;
// for sync thread to check if async thread finished (requires mutex)
bool async_finished_;
// for async thread to check if it's been told to run (requires mutex)
bool async_start_;
// for async thread to check if it's been told to quit (requires mutex)
bool async_abort_;
// The following are only for the synchronous thread to use:
// for sync thread to note its has asked async thread to run
bool async_started_;
// counts up to frame_period before restarting the async thread
int frame_phase_;
int frame_count_; // counts up to startup_frames
int frame_count2_; // counts up to startup_frames for Process method
AwbStatus sync_results_;
AwbStatus prev_sync_results_;
std::string mode_name_;
std::mutex settings_mutex_;
// 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, std::string const &mode_name,
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 async_results_;
void doAwb();
void awbBayes();
void awbGrey();
void prepareStats();
double computeDelta2Sum(double gain_r, double gain_b);
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 manual_r_;
// manual b setting
double manual_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-(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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