title: How to remove radial distortions from images using OpenCV?
body: <p>I think I should be using <code>cv::remap</code> to remove the distortion but can't figure out what the the maps <code>const Mat&amp; map1, const Mat&amp; map2</code> to should be to achieve this.</p>
  
  <p>Should I be using the <code>cv::initUndistortRectifyMap</code> to find out the values? If so, I'd really appreciate an example. I do not have the intrinsic camera parameters or don't know how to calculate them. Thanks.</p>