title: How to deal with RGB to YUV conversion
body: <p>The formula says:</p>
  
  <pre><code>Y = 0.299 * R + 0.587 * G + 0.114 * B;
  
  U = -0.14713 * R - 0.28886 * G + 0.436 * B;
  
  V = 0.615 * R - 0.51499 * G - 0.10001 * B;
  </code></pre>
  
  <p>What if, for example, the U variable becomes negative?</p>
  
  <pre><code>U = -0.14713 * R - 0.28886 * G + 0.436 * B;
  </code></pre>
  
  <p>Assume maximum values for R and G (ones) and B = 0
  So, I am interested in implementing this convetion function in OpenCV,
  So, how to deal with negative values?
  Using float image? anyway please explain me, may be I don't understand something..</p>