#include <opencv2/imgproc.hpp>
int main(int argc, char ** argv) {
    using namespace cv;

    // load
    Mat im = imread("<path/to/opencv_extra>/testdata/shared/baboon.png", IMREAD_GRAYSCALE);
    assert(im.type() == CV_8UC1);

    // convert to 32F, scale values as if original image was 16U
    constexpr auto u8Max = std::numeric_limits<std::uint8_t>::max();
    constexpr auto u16Max = std::numeric_limits<std::uint16_t>::max();
    im.convertTo(im, CV_32FC1, double(u16Max) / double(u8Max));

    // enlarge and create ROIs
    const auto w = im.cols * 5;
    const auto h = im.rows * 5;
    const auto roiW = (w * 2) / 3; // 50% overlap
    Mat imLarge;
    resize(im, imLarge, { w, h });
    const auto roiLeft = imLarge(Rect(0, 0, roiW, h));
    const auto roiRight = imLarge(Rect(w - roiW, 0, roiW, h));

    // correlate
    double response = 0.0;
    Point2d phaseShift = phaseCorrelate(roiLeft, roiRight, cv::noArray(), &response);
    assert(std::isnormal(phaseShift.x) || 0.0 == phaseShift.x);
    assert(std::isnormal(phaseShift.y) || 0.0 == phaseShift.y);
    assert(std::isnormal(response) || 0.0 == response);

    return 0;
}