awb_bayes.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024 Ideas on Board Oy
 *
 * Base class for bayes AWB algorithms
 */
 
#pragma once
 
#include <span>
 
#include <libcamera/controls.h>
 
#include "libcamera/internal/value_node.h"
#include "libcamera/internal/vector.h"
 
#include "awb.h"
#include "interpolator.h"
#include "pwl.h"
 
namespace libcamera {
 
namespace ipa {
 
class AwbBayes : public AwbImplementation
{
public:
    AwbBayes() = default;
 
    int init(const ValueNode &tuningData) override;
    AwbImplementation::Result
    calculateAwb(const AwbStats &stats, unsigned int lux,
             std::array<double, 2> range) override;
    std::optional<RGB<double>> gainsFromColourTemperature(double temperatureK) override;
 
private:
    int readPriors(const ValueNode &tuningData);
 
    void fineSearch(double &t, double &r, double &b, ipa::Pwl const &prior,
            const AwbStats &stats) const;
    double coarseSearch(const ipa::Pwl &prior, const AwbStats &stats,
                std::span<double> range) const;
    double interpolateQuadratic(ipa::Pwl::Point const &a,
                    ipa::Pwl::Point const &b,
                    ipa::Pwl::Point const &c) const;
 
    Interpolator<Pwl> priors_;
    Interpolator<Vector<double, 2>> colourGainCurve_;
 
    ipa::Pwl ctR_;
    ipa::Pwl ctB_;
    ipa::Pwl ctRInverse_;
    ipa::Pwl ctBInverse_;
 
    double transversePos_;
    double transverseNeg_;
};
 
} /* namespace ipa */
 
} /* namespace libcamera */