通过介绍激光扫描测量原理，说明准确地从光刀图像中提取光刀中心位置是影响测量精度的关键因素。提出了基于非均匀有理B样条(NURBS)曲线插值的光刀中心提取方法。通过实验说明该方法重复提取的结果比较稳定，而且将误差控制在0.1个像素以下，从而使重复测量的高度误差在0.02 mm以下。

This paper argues that how to compute the center position of the knife in the image obtained by CCD accurately is a key issue by introducing the principle of laser scanning system. In this paper, a new method based on NURBS curve interpolation is designed. The experiments show that the results computed by this method are stable and the errors are controlled below 0 1 pixel. Thus, the errors in the height direction are less than 0 02 mm.