Zero-Shot Estimation of Radial Distortion of Wide-Angle Camera

In this paper, we propose a novel zero-shot approach for estimating radial distortion of wide-angle cameras using their horizontal and vertical view angles, without the need for calibration images. In the ideal perspective pinhole camera model, focal lengths are directly derived from the view angles and image dimensions of the camera. However, image distortion introduces inconsistencies between the derived vertical and horizontal focal lengths. By exploiting this inconsistency and assuming square pixels, we estimate the radial distortion and focal length of the camera. Experimental results on eight different commercial cameras demonstrate that the calibration accuracy of our proposed zero-shot method is comparable to that of conventional full calibration approaches. This method provides a practical alternative for field applications where individual calibration is challenging or impractical. Furthermore, the camera parameters estimated by our method can serve as appropriate initializations for existing calibration methods.