Undistortion a fisheyelens distortion of a whole image. Note that this is quite a slow process, so it is not really advisable to use this in a vision pipeline leading to control. However, it can be used to find the right undistortion parameter k, and shows that the undistortion functions work. The code also can be used to convert image coordinates from distorted fisheye lenses to undistorted coordinates and back. It takes into account the camera calibration matrix and the distortion of the specific lens. video_thread