Facilitated method to calibrate model parameters of vision sensor for surface measurement

Based on the principle of multiple line structured light, the mathematical model of the surface vision sensor is established. A facilitated calibration approach to easily determine all the model parameters of a surface vision sensor with a planar reference object is proposed. The multiple local world coordinate systems are set up onto the different moving planes respectively. All the local 3D world coordinates of the control points falling on the multiple light stripe plane can be readily obtained by the invariance of the cross ratio. The 3D camera coordinates of the control points can be computed by transformation from the local world frames to the 3D camera coordinate frame. The optimization estimation of the model parameters of the surface vision sensor in the working state can be finished with those control points. The proposed approach greatly reduces the cost of the calibration equipment and simplifies the calibrating procedure, so it can promote the engineering applications of the surface vision sensor handily. It shows that this method is practical in the surface measurement by experiments.