| 摘要 |
PROBLEM TO BE SOLVED: To simply and highly accurately analyze an interference fringe.SOLUTION: The interference fringe analysis method according to the present invention includes: a measurement step of repeating an image-forming of an interference fringe to acquire fringe images of a plurality of frames; a superimposition step of changing a phase of the interference fringe during the acquisition period to superimpose a frame carrier varying by a predetermined frequency in a frame direction on the fringe images of the plurality of frames; a transformation step (S2) of applying Fourier transformation in the frame direction to these overlapped fringe images of the plurality of frames to acquire Fourier spectrums; an extraction step (S3) of extracting a spectrum having a frequency close to the predetermined frequency from the Fourier spectrums and shifting the frequency of the spectrum to an original position side by the predetermined frequency; a restoration step (S4) of applying inverse Fourier transformation in the frame direction to post-shifted spectrum to restore fringe images of a plurality of frames with unnecessary components eliminated therefrom; and a phase calculation step (S5) of calculating a phase distribution of an interference fringe of a fringe image on the basis of the fringe image of a specific frame of post-restored fringe images of a plurality of frames. |
