Error analysis and compensation of single-beam laser triangulation measurement

When measuring the surface of blades based on single-beam laser triangulation principle, depth of field and inclination angle of probe would bring some adverse effects to the inspection process. In order to eliminate this, an adaptive dynamic profile measuring method is proposed, which is based on the B-Spline extrapolation. Therefore, the inclination angle can be controlled by using the direction of the normal line that located in the endpoint of the extrapolation curve, and the measurement precision can be improved by compensating the error in the range of the depth of field that combined with B-Spline extrapolation. The proposed method can overcome the problem that the depth of field of the high-precision triangle laser probe is too small to suit the blade profile measurement with curvature which changes drastically. Meanwhile, it can also improve the precision and efficiency of the blade profile measurement of large scale gas turbine by precise error compensation.