Global calibration method of multi-sensor vision system using skew laser lines

Multi-sensor vision system plays an important role in the 3D measurement of large objects. However, due to the widely distribution of sensors, the problem of lacking common fields of view (FOV) arises frequently, which makes the global calibration of the vision system quite difficult. The primary existing solution relies on large-scale surveying equipments, which is ponderous and inconvenient for field calibrations. In this paper, a global calibration method of multi-sensor vision system is proposed and investigated. The proposed method utilizes pairs of skew laser lines, which are generated by a group of laser pointers, as the calibration objects. Each pair of skew laser lines provides a unique coordinate system in space which can be reconstructed in certain vision sensor’s coordinates by using a planar pattern. Then the geometries of sensors are computed under rigid transformation constrains by taking coordinates of each skew lines pair as the intermediary. The method is applied on both visual cameras with synthetic data and a real two-camera vision system; results show the validity and good performance. The prime contribution of this paper is taking skew laser lines as the global calibration objects, which makes the method simple and flexible. The method need no expensive equipments and can be used in large-scale calibration.