__header__
We are only considering radial not tangential - as the later is said to be neglegable
Best result at typically found by having the software calculate the even terms k2 amd k4
and this line up with Optical theory which shows that this polynomial should
only feature even powers. However many graphic packages seem to use k1 and k3 (adobe? and image magick)
k0 typical is set to 1-k1-k2-k3-k4 (in normalized coordiantes this preserves size)
Based on the papersStraight Lines Have to Be Straight
Automatic Calibration and Removal of Distortion from Scenes of Structured Environments
Frederic Devernay, Olivier Faugeras
Correcting Lens Distortions in Digital Photographs
Wolfgang Hugemann