Adaptive sampling method for laser measuring free-form surface

In order to achieve high accuracy in the laser measuring of free-form surfaces, equal step-length sampling usually involves much more measurement data than necessary. An equal arc-length sampling method based on tangent extrapolation of cubic spline curves is introduced to solve this problem. By this method, step-length is adjusted adaptively according to the slope variation of the sampled curve with arc-length maintained to be constant, thus the small slope region is sampled sparsely while the large slope region is sampled densely. Sampling simulation of a typical surface proves that the data amount of equal arc-length sampling is much less than that of equal step-length sampling under the same circumstance.