| Scanning white-light interferometry of measuring 3-D surface topography has a wide application in the feature. Several methods of measuring 3-D surface topography are introduced in this paper, and the advantages of these methods are compared. The technology of high-precision 3-D surface topography analyzing based on scanning white-light interferometry is described in details.The algorithm of calculating the surface height by analyzing white-light interferograms in frequency domain is implemented, and how to remove the ambiguity in the phase data is mainly analyzed. Then we analyze the effect on the veracity of calculation height due to the parameter of step interval. step number of PZT, gray level of CCD, and the error of PZT. The experiment instruments for measuring by scanning white-light interferometry is constructed, also the program to control the scan of PZT and sample images by CCD is implemented, then a three-dimensional surface profile is obtained through calculation. It is testified that the algorithm by analyzing white-light interferograms in the frequency domain can overcome the problems associated with phase ambiguities. Scanning white-light interferometry increases the portrait measurement range, and its measurement precision achieves the level of nanometer. |
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