Calibration of Nonoverlapping In-Vehicle Cameras With Laser Pointers

Abstract

This paper introduces a new approach to calibrating inward- and outward-facing in-vehicle cameras using a laser pointer. Since inward cameras, which observe the driver's behavior, and outward cameras, which observe the driver's field of view, do not have overlapping views, the conventional calibration methods for stereo cameras cannot be applied directly. A method is presented in which the two cameras can be connected by a laser emitted from a laser pointer. The laser pointer is mounted on a calibration board so that the laser ray's pose within the calibration board's coordinate system can be calculated. Two algorithms are presented based on this idea: the coplanar method and the collinear method. We compare the performance of the two proposed algorithms with the conventional mirror-based method through simulations and experiments. Finally, the laser-based collinear method is applied to the calibration of an in-vehicle camera system. In contrast to other methods, the proposed method is simple, practical, and particularly well suited to the calibration of nonoverlapping in-vehicle cameras in a factory or a garage.