A cylinder based calibration method for integrating a line structured light sensor with a rotation-translation platform

Abstract

As a non-contact measuring apparatus, line structured light sensor (LSLS) can only get one profile of an object without the combination with other motional axes. To achieve the complete 3D measurement, a rotation-translation platform was integrated with the LSLS, and a cylinder based calibration method was also brought out. Firstly, the calibration model was proposed to determine the transformation matrix between the measuring coordinate frame (MCF) and the sensor coordinate frame (SCF). This model relies on the fact that the projection of an arbitrary intersection profile between the laser plane and the cylinder in its axis direction lies on a circle with a radius equal to the cylinder. Then, for a specified rotated angle and translated position of the object, the measured data from the SCF could all be transformed into the MCF, and the complete surface data could be obtained. Finally, a cylinder and a rectangular block were inspected by the proposed method. The surface data was successfully obtained and their intersection profiles indicate a high measuring accuracy of the proposed method. The method was further verified by the measured results of a screw surface.