[OpenCV] save ROI image

void cvSaveROIMat(string filename, Mat &src, Rect ROI)
{
    Mat croppedImage;
    //string filename = "StageType.jpg";
    //Rect myROI(405, 136, 41, 30);
    Mat(src, ROI).copyTo(croppedImage);
    //return croppedImage;
    imwrite(filename, croppedImage);
}