Zero-Shot Calibration of Fisheye Cameras

TL;DR

This paper introduces a zero-shot calibration method for fisheye cameras that estimates parameters without calibration images, using only field of view information, which is practical for wide-angle cameras with distortion.

Contribution

It presents a novel calibration approach that requires no calibration images, leveraging lens design and sensor assumptions, suitable for wide-angle and fisheye cameras.

Findings

Calibration accuracy is comparable to traditional methods.

Method is effective across various commercial cameras.

Provides a practical alternative when calibration images are unavailable.

Abstract

In this paper, we present a novel zero-shot camera calibration method that estimates camera parameters with no calibration image. It is common sense that we need at least one or more pattern images for camera calibration. However, the proposed method estimates camera parameters from the horizontal and vertical field of view information of the camera without any image acquisition. The proposed method is particularly useful for wide-angle or fisheye cameras that have large image distortion. Image distortion is modeled in the way fisheye lenses are designed and estimated based on the square pixel assumption of the image sensors. The calibration accuracy of the proposed method is evaluated on eight different commercial cameras qualitatively and quantitatively, and compared with conventional calibration methods. The experimental results show that the calibration accuracy of the zero-shot method is comparable to conventional full calibration results. The method can be used as a practical alternative in real applications where individual calibration is difficult or impractical, and in most field applications where calibration accuracy is less critical. Moreover, the estimated camera parameters by the method can also be used to provide proper initialization of any existing calibration methods, making them to converge more stably and avoid local minima.