Experimental calibration method for laser triangulation

The laser triangulation has been considered as effective method for 3D configuration measurement. However, the image-spot displacement detected by CCD camera is nonlinear with the object profile depth, that will make measurement difficult. The experimental calibration method was proposed. The screen used as object was moved step by step along with depth, the image-spot displacement data was collected, in which a few of data sets were used to obtain quasi-calibrated curve by least square (LS) method, then error curves for the rest of data sets before calibration were calculated, and error fitting curve was obtained by LS method. The final calibrated curve was obtained by superposing error fitting curve on the quasi-calibrated curve. The measurement results show that the accuracy of the method is up to +15 μm.