基于选择采样的高效迭代相位提取算法

在光学精密测量中，相移干涉法应用广泛。常用的相移器件容易出现相移误差，采用等步距相位提取算法会产生测量误差。基于最小二乘的迭代相位提取算法可以有效消除该类相位提取误差，提高测量精度，但是其迭代过程运行时间长，效率低。提出了一种基于选择采样的迭代相位提取算法，先对干涉图像进行等间隔抽样，降低计算量；再根据对比度滤除干涉图像中低质量像素点，防止误差增大，进行最小二乘迭代求解相位。仿真实验对算法进行了分析和验证，在抽样间隔为2时的选择采样方法与所有像素点全部代入计算相比，运行时间从6.687 s降为0.725 s，均方根误差仅为0.032 9。实验结果证明:选择采样的迭代相位提取算法运算时间短、误差小，非常适合高速相移干涉测量应用。

High-efficiency iterative phase extraction algorithm based on selective sampling

Phase shifting interferometry enjoys a wide application in optical precision measurement. However, the common phase extraction algorithm is vulnerable to phase stepping errors of the phase shifters. The former least square iterative phase extraction algorithm can suppress the influence of phase stepping errors ，but it takes long time. We presented a high-efficiency least square iterative phase extraction algorithm based on selective sampling. Firstly the interferogram pixels were sampled with an equal interval to reduce the calculation time; Next the low quality pixels were filtered out based on the interference contrast to prevent the phase error from growing; In the experiment, when the sampling interval was set to 2, the proposed algorithm took only 0.725 s, compared with the 6.687 s of the former iterative method, and the discrepancy of phase shift was only 0.032 9. The experiment verifies that the proposed algorithm can greatly reduce the calculation time with little compromise of phase extraction accuracy, which is highly suitable for high speed phase shifting measurement applications.