Fast profilometer for the automatic measurement of 3-D object shapes

A fast technique for automatic 3-D shape measurement is proposed and verified by experiments. The technique, based on the principle of phase measurement of the deformed grating pattern which carries the 3-D information of the measured object, can automatically and accurately obtain the phase map or the height information of a measured object at every pixel point without assigning fringe orders and interpreting data in the regions between the fringe orders. Only one image pattern is sufficient for obtaining the phase map. In contrast to the fast Fourier transform based technique, the technique processes a fringe pattern in the real-signal domain instead of the frequency domain by using demodulation and convolution techniques, can process an arbitrary number of pixel points, and is much faster. Theoretical analysis, simulation results, and experimental results are presented.