  The common approach to radial distortion is by the means of polynomial
approximation, which introduces distortion-specific parameters into the camera
model and requires estimation of these distortion parameters. The task of
estimating radial distortion is to find a radial distortion model that allows
easy undistortion as well as satisfactory accuracy. This paper presents a new
class of rational radial distortion models with easy analytical undistortion
formulae. Experimental results are presented to show that with this class of
rational radial distortion models, satisfactory and comparable accuracy is
achieved.

Computer Vision and Pattern Recognition