| 摘要 |
PROBLEM TO BE SOLVED: To provide highly accurate phase information on an observed body without performing high-accuracy wavelength shift control, by applying fringe image analysis computation to fringe image data carrying phase information on the observed body obtained for each wavelength-shifted wavelength to accurately find the amount of wavelength shift and performing a computation using a technique such as interpolation. SOLUTION: An interference fringe image carrying shape information on the observed body with a space carrier fringe superposed thereon is acquired by a CCD imaging camera each time wavelength is shifted by a wavelength variable laser light source (S1). Then, Fourier transformation is applied to the acquired data of the fringe image to extract space carrier frequencies fx and fy (S2), further, the inclinationθx andθy of the observed body relative to a surface are found based on the carrier frequencies fx and fy (S3), and the amountΔλof shift of wavelength is found based on the above found carrier frequencies fx and fy and inclinationθx andθy (S4).
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