干涉测量中低频振动的频谱分析

Spectrum analysis of low frequency vibration in interferometry

  • 摘要: 为了降低振动对移相干涉测量的影响,对振动信号进行频谱分析,分离出对低频振动有贡献的频谱信号,由此验证了PSI(phase-shifting interferometry)算法在2倍移相频率处对振动更加敏感的事实。根据标准的PSI测量步骤,再结合牛顿广义二项式定理,推导出多频率振动影响因子 \gamma ,通过Matlab软件仿真了由标准PSI算法求出的相位误差以及多频率振动影响因子 \gamma 处理后的相位误差,并进行实验加以验证。实验结果显示,经 \gamma 影响因子处理后的波面RMS值和相位误差均低于PSI算法, RMS值减小22倍,相位误差减小20倍。

     

    Abstract: In order to reduce the influence of vibration on phase-shifting interferometry, the spectrum analysis of the vibration signal was carried out to separate the spectrum signal that contributed to the low-frequency vibration, which verified the fact that the phase-shifting interferometry (PSI) algorithm was more sensitive to vibration at 2 times the phase-shifting frequency. According to the standard PSI measurement steps and Newton's generalized binomial theorem, the multi-frequency vibration influence factor γ was derived. The phase error calculated by the standard PSI algorithm and the phase error after the multi-frequency vibration influence factor γ processing were simulated by Matlab software, and the experiment was carried out to verify it. The results show that the RMS value and phase error of the wavefront processed by the γ influence factor are lower than those of the PSI algorithm. The RMS value can be reduced by 22 times and the phase error can be reduced by 20 times.

     

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