Robust Camera Calibration with a Single Image by Planar Homography

In surveillance applications, there are usually dozens of cameras at one site, and quick and easy calibration has primary importance. This paper presents a practical and robust camera calibration method that works with a single image of a planar marker and less sensitive to measurement noise. The method first detects a planar object on the ground plane and estimates a homography between the ground plane and the image plane. Two orthogonal non-infinite vanishing points are then estimated directly from the homography, not from the marker nor scene structure. The proposed method minimizes possible calibration error by choosing the direction of the two vanishing points to be as much different from the direction of the vanishing line as possible. Experimental results on synthetic images show that the proposed homography-based method greatly reduces calibration error in the presence of measurement noise, demonstrating the effectiveness of the method.