opencv - how to save Mat image in filestorage

I want to save a floating point one-channel image & I don’t want to convert it. So I decided to use filestorage class to save it yet I couldn’t quite obtain how to do it from the documentation. And what I tried didn’t work. Can anybody assist me with this?

// Write:FileStorage fs("img.xml", FileStorage::WRITE);Mat img;fs << img;// Read:FileStorage fs("img.xml", FileStorage::READ);Mat img;fs >> img;

Writing to file

cv::FileStorage storage("test.yml", cv::FileStorage::WRITE);storage << "img" << img;storage.release();

Reading from file

cv::FileStorage storage("test.yml", cv::FileStorage::READ);storage["img"] >> img;storage.release();