Some things to definately check
- Make sure the dimensions of your calibration pattern are uneven. Now you have an even amount of cols, which can screw up the calibration setup.
- Make sure you have enough calibration images, using 2 images will never yield a good camera calibration.
- Be sure to calibrate every single region of your camera range, if not, you will have large deformations towards the non calibrated areas.
Good luck!
