抑制高阶谐波误差的随机相移条纹分析算法

高阶谐波和随机相移误差是影响条纹分析精度的主要因素。为了同时解决这两个问题，提出了基于频域滤波的迭代相移算法。该算法采用巴特沃斯低通滤波器，从频域上滤除条纹的高阶谐波分量，再运用最小二乘迭代方法从三帧随机相移条纹图像中提取相位信息。数值模拟和实验结果表明,该算法可有效地抑制由高阶谐波和随机相移引入的波纹误差，误差PV值和RMS值分别为0.368 8 rad和0.025 3 rad，其精度高于传统的三步相移算法和Wang算法。该方法适合于高精度干涉测量和三维物体表面轮廓测量。

Analysis algorithm of randomly phase-shifting fringes for reducing high order harmonic error

High-order harmonics and phase shift miscalibration are the two main systematic error sources that affect the accuracy of fringe analysis. To deal with these problems simultaneously, an iterative phase-shifting algorithm based on frequency filtering is proposed. The proposed method filters the high-order harmonics in spectrum domain by using the Butterworth low-pass filter, and then extracts the phase from three frames of randomly phase-shifting fringes by using the least-squares iterative algorithm. Numerical simulation and experimental results show that the proposed method can effectively reduce the ripple caused by high-order harmonics and randomly phase-shifting error and thus can increase the measurement accuracy. The proposed algorithm is suitable for the high-accuracy interferometry and three-dimensional profilometry measurement.