Fourier transform parallel slit analytical manner and

摘要

PROBLEM TO BE SOLVED: To provide a stable analysis result by making it possible to uniquely and stably perform determination work on whether a phase is positive or negative by comparing a spectrum corresponding to an existing carrier frequency whose polarity is unknown with a spectrum obtained by additionally superimposing thereon an additional carrier frequency whose polarity is known to determine whether the existing carrier frequency is positive or negative.;SOLUTION: An original interference fringe image with the existing space carrier frequency superimposed thereon is obtained by a CCD imaging camera (T1), the fringe image data are Fourier-transformed (T2), and the coordinate of the first spectrum corresponding to the existing frequency is obtained in a frequency coordinate system (T3). Then, the additional carrier frequency is additionally superimposed on the original fringe (T4), an interference fringe image for comparison therewith is obtained by the imaging camera (T5), the fringe image data for comparison are Fourier-transformed (T6), and the coordinate of the second spectrum is obtained in the coordinate system (T7). By comparing the coordinates of the two spectra with each other, whether the existing frequency is positive or negative is determined (T8) to determine whether the phase is positive or negative.;COPYRIGHT: (C)2002,JPO