awb.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2021, Ideas On Board
 *
 * IPU3 AWB control algorithm
 */

#pragma once

#include <vector>

#include <linux/intel-ipu3.h>

#include <libcamera/geometry.h>

#include "algorithm.h"

namespace libcamera {

namespace ipa::ipu3::algorithms {

/* Region size for the statistics generation algorithm */
static constexpr uint32_t kAwbStatsSizeX = 16;
static constexpr uint32_t kAwbStatsSizeY = 12;

struct Accumulator {
    unsigned int counted;
    struct {
        uint64_t red;
        uint64_t green;
        uint64_t blue;
    } sum;
};

class Awb : public Algorithm
{
public:
    Awb();
    ~Awb();

    int configure(IPAContext &context, const IPAConfigInfo &configInfo) override;
    void prepare(IPAContext &context, const uint32_t frame,
             IPAFrameContext &frameContext,
             ipu3_uapi_params *params) override;
    void process(IPAContext &context, const uint32_t frame,
             IPAFrameContext &frameContext,
             const ipu3_uapi_stats_3a *stats,
             ControlList &metadata) override;

private:
    /* \todo Make these structs available to all the ISPs ? */
    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;
        }
    };

    struct AwbStatus {
        double temperatureK;
        double redGain;
        double greenGain;
        double blueGain;
    };

private:
    void calculateWBGains(const ipu3_uapi_stats_3a *stats);
    void generateZones();
    void generateAwbStats(const ipu3_uapi_stats_3a *stats);
    void clearAwbStats();
    void awbGreyWorld();
    static constexpr uint16_t threshold(float value);
    static constexpr uint16_t gainValue(double gain);

    std::vector<RGB> zones_;
    Accumulator awbStats_[kAwbStatsSizeX * kAwbStatsSizeY];
    AwbStatus asyncResults_;

    uint32_t stride_;
    uint32_t cellsPerZoneX_;
    uint32_t cellsPerZoneY_;
    uint32_t cellsPerZoneThreshold_;
};

} /* namespace ipa::ipu3::algorithms */

} /* namespace libcamera*/