Blind Rectification of Radial Distortion by Line Straightness

Abstract

Lens distortion self-calibration estimates the distortion model using arbitrary images captured by a camera. The estimated model is then used to rectify images taken with the same camera. These methods generally use the fact that built environments are line dominated and these lines correspond to lines on the image when distortion is not present. The proposed method starts by detecting groups of lines whose real world correspondences are likely to be collinear. These line groups are rectified, then a novel error function is calculated to estimate the amount of remaining distortion. These steps are repeated iteratively until suitable distortion parameters are found. A feature selection method is used to eliminate the line groups that are not collinear in the real world. The method is demonstrated to successfully rectify real images of cluttered scenes in a fully automatic manner.