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#ifndef __OPENCV_STITCHING_BLENDERS_HPP__
#define __OPENCV_STITCHING_BLENDERS_HPP__

#include "opencv2/core/core.hpp"

namespace cv {
namespace detail {


// Simple blender which puts one image over another
class CV_EXPORTS Blender
{
public:
    virtual ~Blender() {}

    enum { NO, FEATHER, MULTI_BAND };
    static Ptr<Blender> createDefault(int type, bool try_gpu = false);

    void prepare(const std::vector<Point> &corners, const std::vector<Size> &sizes);
    virtual void prepare(Rect dst_roi);
    virtual void feed(const Mat &img, const Mat &mask, Point tl);
    virtual void blend(Mat &dst, Mat &dst_mask);

protected:
    Mat dst_, dst_mask_;
    Rect dst_roi_;
};


class CV_EXPORTS FeatherBlender : public Blender
{
public:
    FeatherBlender(float sharpness = 0.02f);

    float sharpness() const { return sharpness_; }
    void setSharpness(float val) { sharpness_ = val; }

    void prepare(Rect dst_roi);
    void feed(const Mat &img, const Mat &mask, Point tl);
    void blend(Mat &dst, Mat &dst_mask);

    // Creates weight maps for fixed set of source images by their masks and top-left corners.
    // Final image can be obtained by simple weighting of the source images.
    Rect createWeightMaps(const std::vector<Mat> &masks, const std::vector<Point> &corners,
                          std::vector<Mat> &weight_maps);

private:
    float sharpness_;
    Mat weight_map_;
    Mat dst_weight_map_;
};

inline FeatherBlender::FeatherBlender(float _sharpness) { setSharpness(_sharpness); }


class CV_EXPORTS MultiBandBlender : public Blender
{
public:
    MultiBandBlender(int try_gpu = false, int num_bands = 5, int weight_type = CV_32F);

    int numBands() const { return actual_num_bands_; }
    void setNumBands(int val) { actual_num_bands_ = val; }

    void prepare(Rect dst_roi);
    void feed(const Mat &img, const Mat &mask, Point tl);
    void blend(Mat &dst, Mat &dst_mask);

private:
    int actual_num_bands_, num_bands_;
    std::vector<Mat> dst_pyr_laplace_;
    std::vector<Mat> dst_band_weights_;
    Rect dst_roi_final_;
    bool can_use_gpu_;
    int weight_type_; //CV_32F or CV_16S
};


//////////////////////////////////////////////////////////////////////////////
// Auxiliary functions

void CV_EXPORTS normalizeUsingWeightMap(const Mat& weight, Mat& src);

void CV_EXPORTS createWeightMap(const Mat& mask, float sharpness, Mat& weight);

void CV_EXPORTS createLaplacePyr(const Mat &img, int num_levels, std::vector<Mat>& pyr);
void CV_EXPORTS createLaplacePyrGpu(const Mat &img, int num_levels, std::vector<Mat>& pyr);

// Restores source image
void CV_EXPORTS restoreImageFromLaplacePyr(std::vector<Mat>& pyr);
void CV_EXPORTS restoreImageFromLaplacePyrGpu(std::vector<Mat>& pyr);

} // namespace detail
} // namespace cv

#endif // __OPENCV_STITCHING_BLENDERS_HPP__