A simplified method for the extrinsic calibration of structured-light sensors using a single-ball target

In this paper, a single-ball-target-based approach is presented for the extrinsic calibration of a multiple-axis, structured-light scanning system. Since the output of the structured-light sensor is 2D data, the system mathematical model is directly built as the transformation from 2D sensor coordinate system (laser plane) to Cartesian world coordinate system, not 3D non-orthogonal skewed coordinate system to Cartesian world coordinate system. By measuring a fixed point (ball center) using the sensor, “conjugate pairs” are identified for solving this model. An algorithm for determining the position of the CMM scanning axis where the laser plane passes through the ball center is proposed to enable this sensor to measure the fixed point. The calibration procedure facilitates on-line use. Experiments show that the calculation accuracy of the transformation matrix is adequate for common use.