对用到的做一个记录，持续记录。
1.图片的读取
CV_LOAD_IMAGE_UNCHANGED = -1 ( = cv::IMREAD_UNCHANGED),
CV_LOAD_IMAGE_GRAYSCALE = 0 ( = cv::IMREAD_GRAYSCALE),
CV_LOAD_IMAGE_COLOR = 1 ( = cv::IMREAD_COLOR),
CV_LOAD_IMAGE_ANYDEPTH = 2 ( = cv::IMREAD_ANYDEPTH),