基于二维傅里叶变换的单帧干涉图相位提取方法

针对大口径光学元件干涉测试过程中，测试装置和干涉腔长较大，气流扰动和环境振动对移相测试过程产生影响等问题，采用一种基于二维傅里叶变换的单帧干涉图处理方法，只需要对一幅空间载频干涉条纹图进行处理即可获得待测相位，具有抗振测试的优点。对该方法的基本原理和算法过程进行分析，并对近红外大口径移相平面干涉仪中600 mm口径的光学平晶进行了面形测试。实验结果表明:采用该方法所得波面峰谷值(PV)为0.112，波面均方根值(RMS)为0.014，与移相算法所得波面数据相比，波面峰谷值偏差不到(1/500)；波面均方根值(RMS) 偏差几乎为零。

Phase extraction for single frame interferogram-based on 2D Fourier transform

For the interferometric testing of optical elements with large aperture, due to large testing device and interferometric cavity length, the process of phase shifting interferometry was affected by airflow disturbance and environmental vibration. In order to overcome the above factors, a single interferogram processing method based on two-dimensional fast Fourier transform(FFT) was proposed. This method only required one single spatial carrier fringe pattern to obtain the phase, which had the advantage of anti-vibration testing. The basic principle and the process of algorithm were analyzed, and the optical element with 600 mm large aperture in the near-infrared phase-shifting Fizeau interferometer was tested. Experimental results show that the peak to valley (PV) value and root mean square (RMS) value of the wavefront obtained by FFT method are 0.112 λ and 0.014 λ respectively, compared with the results obtained by phase-shifting method, there are a difference less tham (1/500)λ in PV and almost zero difference in RMS.