Model-free Radial Distortion Correction of Wide Angle Lenses using Vanishing Points

In this paper, we proposed a new model-free method for correcting the radial distortion of a strong wide-angle lens using vanishing points in a single image. The key idea is to use a 3D concave calibration rig with three planar patterns aligned orthogonally with each other, so that the parallelism of the line patterns, orthogonality and concavity of the rig enable us to cope with the distortion of whole field of view (FOV) caused even by a strong FOV lens such as fish-eye lens efficiently using a single image. The first step of this method is to identify vanishing points in the distorted image with curved lines. And then, we estimate the center of distortion by the intersection of lines connecting the vanishing points. And, the undistorted straight lines and ideal vanishing are recovered using geometric constraints, so that the correspondences between distorted and undistorted images are established. Since the proposed algorithm assumes a general radial lens distortion model that is independent on specific parametric model, our method is model-free. So, it can be applied to various types of lenses. Experimental results demonstrate the effectiveness and robustness of the proposed method.