title: OpenCV findChessboardCorners very slow
body: <p>dose anybody know why is <strong>cv::findChessboardCorners</strong> horribly slow on all images with more than one mega-pixel ( > 1 000 000 pixles ).</p>
  
  <p>As a workaround I down-sample my images to fit this bound, but I would like to know if it can be solved more "elegantly".</p>
  
  <p>Thanx</p>