On-line three-dimensional point cloud data extraction method for scan-tracking measurement of irregular surface using bi-Akima spline

Point cloud data extraction is an important process in scan-tracking measurement. In this paper, a new method of on-line three-dimensional point cloud data extraction for scan-tracking measurement is proposed for reducing extremely dense sampled data while maintaining data accuracy during the real-time scan-tracking measuring process. It is inspired from sketch paintings: First outlining the broad contour of the curve and then revising local details till the interpolated curve satisfies the required accuracy. This method adopts bi-Akima spline interpolation for connecting acquired points in NC machining or for point data fitting in reverse engineering. It can reduce efficiently the amount of point data with a smaller data reduction ratio and a smoother machined/fitted surface than conventional three-dimensional chordal method.