title: How to implement Optical Flow tracker?
body: <p>I'm using the OpenCV wrapper - Emgu CV, and I'm trying to implement a motion tracker using Optical Flow, but I can't figure out a way to combine the horizontal and vertical information retrieved from the OF algorithm:</p>
  
  <pre><code>flowx = new Image&lt;Gray, float&gt;(size);
  flowy = new Image&lt;Gray, float&gt;(size);
  
  OpticalFlow.LK(currImg, prevImg, new Size(15, 15), flowx, flowy);
  </code></pre>
  
  <p>My problem is not knowing how to combine the info of vertical and horizontal movement in order to build the tracker of moving objects? A new image?</p>
  
  <p>By the way, there is a easy way to display the flow info on the current frame?</p>
  
  <p>Thanks in advance.</p>