High-precision optical stripe phase extraction method

Abstract

The invention discloses a high-precision optical stripe phase extraction method which comprises the following steps of: performing adaptive window Fourier transform on an optical stripe by using a formula; then, performing inverse Fourier transform on complete first-level frequency spectrum to obtain a first-level frequency spectrum light intensity component I1(x); and extracting the phase of each point of the optical stripe by using a formula. The phase extraction method of the invention has the characteristic that the telescopic factor a corresponding to each point in the optical stripe is adaptively changed. Compared with the traditional phase extraction technology, the invention has higher phase extraction precision.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to an optical fringe phase extraction method. Background technique [0002] Optical precision measurement using optical fringes (such as interference fringes, projected fringes) is a widely used technique. The automatic analysis of optical fringes is the key to this technology. Optical fringe phase extraction technology is a widely used automatic optical fringe analysis technology. The optical fringe phase extraction technology includes Fourier transform technology, phase shift technology and so on. Phase-shift technology requires multiple sinusoidally distributed fringes, which is generally not suitable for dynamic measurement, while Fourier transform technology only needs one fringe, which is especially suitable for dynamic measurement. In the Fourier transform technology, it is not strictly required that the optical fringes are sinusoidally distributed, but it is r...

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Problems solved by technology

], this window selection method, when the instantaneous frequency of the optical fringe is high, the window is narrow, resulting in low frequency resolution, which cannot guarantee the highest frequency resolution without aliasing, so it cannot Guaranteed to obtain high phase extraction accuracy

We have also proposed to set the window size according to the instantaneous frequency gradient, which improves the above situation, but requires the use of an integral inequality and an empirical threshold to judge the size of the instantaneous frequency gradient. The empirical threshold brings great inconvenience to the actual operation [Jingang Zhong and Huiping Zeng, "Multiscale windowed Fourier transform for phase extraction of fringe patterns," Applied Optics, Vol.46, No.14, 2670-2675, 5 / 2007.]

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