Radial image distortion is a frequently observed defect when using wide angle, low focal length lenses. In this paper a new method for its calibration and removal is presented. An inverse distortion model is derived that is accurate to a sub-pixel level, over a broad range of distortion levels. An iterative technique for estimating the models parameters from a single view is also detailed. Results on simulated and real images clearly indicate significantly improved performance compared to existing methods.