Joint calibration of a camera and a laser range finder from grid calibration target

Joint calibration of the laser range finder (LRF) and the camera is the foundation of their information fusion and it is also the key step in visual measurement. In this paper, a joint calibration method based on the feature points matching of a grid calibration target is proposed. Firstly, the camera and the LRF internal parameters are calibrated. Then the cloud point data which LRF output is dealt to be triangular mesh. Normal vector of each triangular mesh is calculated, though projecting normal vector to color space, the normal vector (NV) image is constructed. Detecting the edges of the grid calibration target in NV image and color image, intersections of the edges are regard as the feature points. Finally the transformation matrix between LRF coordinate system and image coordinate system is solved by the feature points.