随机步长光栅投影干涉图极值特征相位解算

Phase Solution of Extremum Feature of Grating Projection Interferogram with Random Step Size

针对传统移相干涉测量中需要多帧干涉图,对测量设备稳定性要求高,相位提取速度较慢的问题,提出了一种基于干涉图特殊极值特征的两帧随机相移干涉图相位解算方法。该方法仅需两帧干涉图,利用高斯高通滤波器对具有随机相移量的两帧干涉图分别进行处理以滤除其背景,再通过干涉图中一定数量的特殊极值特征像素点来确定两帧干涉图之间的相移量,进而根据反正切相移相位提取算法对干涉图的相位进行解算。仿真模拟和实测对比结果表明,该方法可通过两帧随机相移干涉图获取较高精度的测量相位,大大减少了测量系统误差对相位解算结果的影响,对于256×256 pixels的石膏像眼部干涉图,执行时间在0.02 s以内,相位提取速度较快。

For the problems that the traditional phase-shifting interferometry required multiple interferograms, which thus required high stability of the measurement equipment, resulting in slow phase extraction, a phase solving method of two-frame random phase-shifting interferograms based on the special extremum feature of the interferogram was proposed. This method required only two-frame interferograms. The two-frame interferograms with random phase shifting were processed separately by Gaussian high-pass filter to filter out their backgrounds. Then the phase shifting between these two interferograms was determined by a certain number of special extremum feature pixels in the interferogram. Finally, the phase of the interferogram was calculated according to the phase-shifting phase extraction algorithm of the arctangent function. The comparison results of simulation and actual measurement show that this method can obtain high-precision measurement phase through two-frame random phase-shifting interferograms, greatly reducing the influence of measurement system errors on the phase solving results. For the 256×256 pixels interferogram of the eye part of the plaster model, the execution time is within 0.02 s, which is fast for phase extraction.