Surface Reconstruction and Visualization Measurement in the Parallel Astigmatic Confocal System

In the parallel astigmatic confocal system, the in-focus positions of the whole-field probing points are extracted by means of searching the "zero" points at the detecting curves which come from the system\´s sequential images. A 3-D surface profile is reconstructed based on the "zero" points in the detecting curves, than the surface profile parameters of the microstructure are measured. Bi-cubic-spline interpolation curve surface fitting method is used to reconstruct the 3-D surface profile, which passes the in-focus position of the probing points. High subdivision rate can improve the geometric continuity and accuracy of the 3-D surface reconstructed. In the course of visualization measurement for the microstructure, the 3-D surface profile parameters are evaluated based on the points picked from the bi-cubic-spline interpolation curve surface rather than from the local triangular plane in the 3-D surface profile. The measurement accuracy for the 3-D profile parameters of the microstructure could be advanced.