lsc_polynomial.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2024, Ideas On Board
 *
 * Polynomial based lens shading correction
 */
#pragma once
 
#include <array>
#include <map>
#include <span>
#include <vector>
 
#include <libcamera/geometry.h>
 
#include "libcamera/internal/value_node.h"
 
#include "lsc_base.h"
 
namespace libcamera {
 
namespace ipa {
 
namespace lsc {
 
class Polynomial
{
public:
    Polynomial(double cx = 0.0, double cy = 0.0, double k0 = 0.0,
           double k1 = 0.0, double k2 = 0.0, double k3 = 0.0,
           double k4 = 0.0)
        : cx_(cx), cy_(cy), cnx_(0), cny_(0),
          coefficients_({ k0, k1, k2, k3, k4 })
    {
    }
 
    double sampleAtNormalizedPixelPos(double x, double y) const;
    double getM() const;
    void setReferenceImageSize(const Size &size);
 
private:
    double cx_;
    double cy_;
    double cnx_;
    double cny_;
    std::array<double, 5> coefficients_;
    Size imageSize_;
};
 
} /* namespace lsc */
 
class LscPolynomial : public LscImplementation
{
private:
    using PolynomialComponents = std::map<std::string, lsc::Polynomial, std::less<>>;
    using PolynomialComponentsMap = std::map<unsigned int, PolynomialComponents>;
 
public:
    int parseLscData(const ValueNode &sets,
             const LscDescriptor &descriptor) override;
 
    LscImplementation::ComponentsMap
    sampleForCrop(const Rectangle &cropRectangle,
              std::vector<double> xPos, std::vector<double> yPos) override;
 
private:
    std::vector<float> samplePolynomial(const lsc::Polynomial &poly,
                        std::span<const double> xPositions,
                        std::span<const double> yPositions,
                        const Rectangle &cropRectangle);
    PolynomialComponentsMap lscData_;
};
 
} /* namespace ipa */
 
} /* namespace libcamera */