DISTORTION CORRECTION OF FISHEYE LENSES USING A NON-PARAMETRIC IMAGING MODEL

摘要

Fisheye lenses are often used to enlarge the field of view of a conventional camera. But the images taken with a camera with fisheye lenses have severe distortions. This paper presents a new non-parametric imaging modeling method to transform the distorted images into the quasi-perspective images. The non-parametric model is a mapping from the rays captured by the camera to their corresponding image points. The non-parametric model of the fisheye camera can be conveniently obtained using the inner surface of a hemispherical calibration pattern. The key distinct characteristic between the parametric method and the non-parametric method is that: the parametric distortion model does not often fit the real distortions in the imaging system well, and the non-parametric model can fit the imaging system better if there are more control points on the hemispherical pattern. Our experimental results show that the fisheye images are corrected satisfactorily using the non-parametric model via a simple look-up table.