【摘要】 传统的四步相移算法在分析相位掩模干涉图时存在相移值误差、分辨力降低和相干噪声等不足,从而影响了动态干涉仪的性能。为了提高相位掩模干涉图的分析精度,提出了一种基于低通滤波的相位解调方法。该方法根据相位掩模引入相位的空间频率远大于被测相位空间频率的最大值,采用低通滤波的方法提取相位信息。数值分析结果表明,该方法的精度高于传统四步相移算法。分析干涉图的信噪比,合理选择低通滤波器,可进一步提高相位解调的精度。更多还原

【Abstract】 The traditional four-step phase shifting algorithm has some limitations(such as phase shift error,low resolution and coherent noise) for processing of phase-masked interferograms,which affects the performance of the dynamic phase-masked interferometer.In order to improve the analysis accuracy of the phase-masked interferogram,a phase demodulation method based on low-pass filtering is proposed.According to the fact that the phase introduced by phase mask has much higher spatial frequency than the measured phase,the proposed method extracts the phase from phase-masked interferograms by a low-pass filtering method.Numerical simulation shows that the proposed method has a higher accuracy than the traditional four-step phase shifting algorithm.The accuracy of the proposed method can be further improved by choosing a proper low-pass filter according to the signal-to-noise ratio of the phase-masked interferogram.更多还原