agc_mean_luminance.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024 Ideas on Board Oy
 *
 agc_mean_luminance.h - Base class for mean luminance AGC algorithms
 */
 
#pragma once
 
#include <map>
#include <memory>
#include <tuple>
#include <vector>
 
#include <libcamera/base/utils.h>
 
#include <libcamera/controls.h>
 
#include "libcamera/internal/yaml_parser.h"
 
#include "exposure_mode_helper.h"
#include "histogram.h"
#include "pwl.h"
 
namespace libcamera {
 
namespace ipa {
 
class AgcMeanLuminance
{
public:
    AgcMeanLuminance();
    virtual ~AgcMeanLuminance();
 
    struct AgcConstraint {
        enum class Bound {
            Lower = 0,
            Upper = 1
        };
        Bound bound;
        double qLo;
        double qHi;
        Pwl yTarget;
    };
 
    void configure(utils::Duration lineDuration, const CameraSensorHelper *sensorHelper);
    int parseTuningData(const YamlObject &tuningData);
 
    void setExposureCompensation(double gain)
    {
        exposureCompensation_ = gain;
    }
 
    void setLux(unsigned int lux)
    {
        lux_ = lux;
    }
 
    void setLimits(utils::Duration minExposureTime, utils::Duration maxExposureTime,
               double minGain, double maxGain, std::vector<AgcConstraint> constraints);
 
    const std::map<int32_t, std::vector<AgcConstraint>> &constraintModes() const
    {
        return constraintModes_;
    }
 
    const std::map<int32_t, std::shared_ptr<ExposureModeHelper>> &exposureModeHelpers() const
    {
        return exposureModeHelpers_;
    }
 
    ControlInfoMap::Map controls()
    {
        return controls_;
    }
 
    std::tuple<utils::Duration, double, double, double>
    calculateNewEv(uint32_t constraintModeIndex, uint32_t exposureModeIndex,
               const Histogram &yHist, utils::Duration effectiveExposureValue);
 
    double effectiveYTarget() const;
 
    void resetFrameCount()
    {
        frameCount_ = 0;
    }
 
private:
    virtual double estimateLuminance(const double gain) const = 0;
 
    int parseRelativeLuminanceTarget(const YamlObject &tuningData);
    int parseConstraint(const YamlObject &modeDict, int32_t id);
    int parseConstraintModes(const YamlObject &tuningData);
    int parseExposureModes(const YamlObject &tuningData);
    double estimateInitialGain() const;
    double constraintClampGain(uint32_t constraintModeIndex,
                   const Histogram &hist,
                   double gain);
    utils::Duration filterExposure(utils::Duration exposureValue);
 
    utils::Duration filteredExposure_;
    mutable bool luxWarningEnabled_;
    double exposureCompensation_;
    Pwl relativeLuminanceTarget_;
    uint64_t frameCount_;
    unsigned int lux_;
 
    std::vector<AgcConstraint> additionalConstraints_;
    std::map<int32_t, std::vector<AgcConstraint>> constraintModes_;
    std::map<int32_t, std::shared_ptr<ExposureModeHelper>> exposureModeHelpers_;
    ControlInfoMap::Map controls_;
};
 
} /* namespace ipa */
 
} /* namespace libcamera */