A simple and effective extrinsic calibration method of a camera and a single line scanning lidar

In this paper we propose an extrinsic calibration method of regular camera and single line scanning li-dar which are widely utilized together. Based on a long ignored aspect that infra-red (IR) source for commonly used lidars lies in the response range of regular cameras, we employ an auxiliary IR filter (blocking natural light and letting IR pass) in order for camera to image the scan traces of lidar by prolonging exposure time. Then by scanning V-shaped target such as the intersection of two smooth walls, corresponding lines (or points) on scan plane and image are found through line fitting. With these high confident correspondences, extrinsic parameters (known camera) or a planar homography (unknown camera) can easily be calculated. Furthermore, two evaluation methods, namely line alignment error and two-view point alignment error, are developed. Experiments show that our method greatly simplifies the calibration procedure and outperforms the state-of-the-art in accuracy by using only one-tenth of the calibration data.