相移阴影叠栅干涉场的相位（高度）存在非线性关系，而传统的相移阴影叠栅技术往往忽略了相位与高度的非线性关系，从而在测量系统中引入测量误差。对此提出了一种基于迭代相位解调自调算法相移阴影叠栅技术，该方法利用最小二乘技术获得相移量估算值，利用该估算值通过迭代算法消除相移阴影叠栅的全场相位误差，从而得到正确的相位分布。模拟计算表明该方法可以有效解决相移不均产生的相位测量误差问题，且可实现光栅移动量的精确估算，其误差不超过3.4%。对比实验进一步说明了所提出方法的正确性和优越性。

Due to the nonlinear nature of height-phase relation, the traditional phase shifting shadow Moiré can only be fulfilled under certain approximations. Thus a systematic error source is introduced. Therefore, a general phase extraction algorithm with arbitrary phase step based on iterative self-tuning algorithm is proposed. In the proposed method, the estimation of phase shift is calibrated by the least squares fitting in spatial domain. Then, the accurate phase is obtained by an iterative process. Numerical experiments show that the proposed method can effectively minimize the nonuniform phase-shift error and can determinate the precise phase shifts during the process of demodulation. In the noisy case, the calibration error of the proposed is less than 3.4%. The experimental results prove the effectiveness of this technique. The proposed method improves measurable depth range.