移相干涉技术中移相器的自校正方法

A Self-Correcting Method of Phase Shifter in Phase Shifting Interferometry

移相干涉技术（ＰＳＩ）是８０年代兴起的一门干涉图形自动识别技术，移相器作为移相干涉技术的关键部件其移相误差将直接影响到移相干涉技术的干涉图的识别精度。本文提出了一种移相器的自校正方法，即利用移相干涉仪的自身系统，通过快速傅里叶方法，对移相器进行逐步逼近校正。结合移相式红外干涉仪的研制，给出了一组移相器的自动校正的实验，实验表明，校正后的移相器的非线性误差可由原来的５％降低到０．２％。

A selfcorrecting method to calibrate the error of phase shifter is presented. Firstly, the fast Fourier transform (FFT) was used to anlayze the carrier frequency fringes, the characteristic curve of phase shifter was obtained from a series of carrier interferograms by FFT. Using this curve, then the phase shifter was corrected by an iterative selfcorrecting process relying on the interferometer. The selfcorrecting experiment with IR interferometer shown that the nonlinearity of phase shifter was reduced from 5% to 0.2%.