title: Concatenate Mat in OpenCV
body: <p>I have a couple of images in <code>Mat</code> objects all with same dimensions
  I'd like to create one bix <code>cv::Mat</code> object to hold them all</p>
  
  <p>So the dimension of the new matrix is: <em>widthNew = widthOld x number of matrices</em>, height remains unchanged.</p>
  
  <p>I found that such a copy could be done using:</p>
  
  <pre><code>void cvCopy(const CvArr* src, CvArr* dst, const CvArr* mask=NULL)
  </code></pre>
  
  <p>but then, how could the mask be defined three different times for the three matrices?.</p>
  
  <p>Regards,
  Moataz</p>