针对用于现场测试的移相干涉测量系统对振动的高度敏感而过于复杂的问题,提出一种可用于现场测试的小型化、抗振动的时频域波前检测方法.采集一系列连续移相的干涉图,通过对干涉图中各点时序光强序列的频谱进行宽带滤波获取相位统计信息.线性拟合相位统计信息后,对随机噪声的影响进行了多次取平均,将环境振动、移相非线性等非随机性扰动的影响归结为一个与像素坐标无关的值,实现了抗扰动的目的.仿真实验统计了λ/100波长精度要求下最大可承受振动的幅频积及其变化规律.研究结果验证了本方法的可行性,并为本方法在小型化移相干涉仪中的应用提供了依据.
Because of its high sensitivity to vibrations, the phase-shifting interferometry system is often quite complicated. A time-frequency domain (TFD) method is proposed in this research, which could make the system in compact for field testing. A large number of interferograms are captured. For the particular pixels in interferograms, a series of distorted phase is obtained through wide bandwidth filtering and reverse Fourier transform of the spectrum of intensity series. Then the linear fit method is used. For a large enough number of interferograms, a linear fit of the distorted phase efficiently could reduce random noises towards zero, and astringe other nonrandom disturbances into a nonzero data which is independent to index of pixels and therefore dose not influence the shape of the whole wave front. Under a precise of λ/100, the maximum amplitude-frequency product (AFP) of anti-vibration capability was obtained by simulation, which verifies the feasibility of the method and lays the foundation for application of the method in compact system.