title: Difference of OpenCV Mat types
body: <p>What are the differences between OpenCV <code>cv::Mat</code> types?</p>
  
  <p>To be more specific, what is the difference between <code>CV_64F</code> and <code>CV_64FC1</code> or <code>CV_64FC2</code>? Which one should I use when I'm creating a <code>cv::Mat</code> object which will have <code>double</code> values?</p>