Mat test_bilateral_filter(cv::Mat imageS, double sigmaS, double sigmaR, double tol, bool sw_imshow, bool last)
{
    //cv::Mat imageS = cv::imread(pathS, -1);
    if (imageS.empty())
    {
        std::cerr << "Source image loading failed!" << std::endl;
        return imageS;
    }

    std::cerr << "[Loaded Image]" << std::endl;
    std::cerr << cv::format("Source: \"\"  # (w,h,ch)=(%d,%d,%d)",  imageS.cols, imageS.rows, imageS.channels()) << std::endl;
    std::cerr << "[Filter Parameters]" << std::endl;
    std::cerr << cv::format("sigmaS=%f  sigmaR=%f  tolerance=%f", sigmaS, sigmaR, tol) << std::endl;

    cv::Mat src;
    imageS.convertTo(src, CV_64F);

    std::vector<cv::Mat_<double> > srcsp;
    cv::split(src, srcsp);

    std::vector<cv::Mat_<double> > dstsp0(src.channels());
    //std::vector<cv::Mat_<double> > dstsp1(src.channels());
    for (int c = 0; c<int(src.channels()); ++c)
    {
        dstsp0[c] = cv::Mat_<double>(src.size());
        //dstsp1[c] = cv::Mat_<double>(src.size());
    }

    cv::TickMeter tm;
    // Original bilateral filtering
    tm.start();
    //for (int i = 0; i < 1; i++) {
        for (int c = 0; c < src.channels(); ++c)
            apply_bilateral_filter(srcsp[c], dstsp0[c], sigmaS, sigmaR);
    //}

        if (last)
        {
            for (int c = 0; c < src.channels(); ++c)
            {
                for (int i = 0; i < src.rows; i++)
                {
                    for (int j = 0; j < src.cols; j++)
                    {
                        double p = dstsp0[c](i, j);
                        p = ((p /255.0f) / 24) * 24;
                        dstsp0[c](i, j) = p;
                    }
                }
            }
        }
    tm.stop();
    std::cerr << cv::format("Original BF:     %7.1f [ms]", tm.getTimeMilli()) << std::endl;
    tm.reset();

    cv::Mat dst0, dst1;
    cv::merge(dstsp0, dst0);

    const double tone = 256.0;
    if (sw_imshow)
    {
        cv::imshow("dst0", dst0 / (tone - 1.0));/// (tone - 1.0));
        cv::waitKey();
    }
    return dst0;
}