title: OpenCV image conversion goes wrong
body: <p>I have an algorithm that does some stuff. Among them, there is a conversion that works fine if I'm working on a <code>CV_8UC3</code> image but goes wrong if the file type is <code>C_16UC3</code>.
  This is some code:</p>
  
  <pre><code>//new image is created
  Mat3w img(100,100,Vec3w(1000,0,0));
  //Image Conversion - ERROR!
  cv::Mat inputSource;
  //saving the image here will work
  img.convertTo(inputSource, CV_64FC3);
  //saving the image here will not work -&gt; black image
  </code></pre>
  
  <p>The problem is that the <code>CV_16UC3</code> image's processing result is an image of the right dimensions but fully black.
  The problem is in the conversion because saving the image right before will give a legit one while saving it right after will give an almost completely white one.</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>I made some changes: cut off some useless code and added the inputSource declaration.
  Now, while I was trying stuff, I arrived at the conclusion that either I haven't understood the CV Types, or something strange is happening.
  I always thought that the number in the type was indicating the number of bits per channel. So, in my head, <code>CV_16UC3</code> is a 3 channel with 16bits per channel. That idea is strengthened by the fact that the image I save during as tests (before the img.convertTo) actually had matching bits per channel number. The strange thing, is that the saved inputSource (type <code>CV_64FC3</code>) is an 8bpc image.</p>
  
  <p>What's am I missing?</p>