在对拓展重叠关联迭代引擎算法(ePIE)成像的轴向距离偏差问题进行详细分析的基础上指出，轴向距离偏差对再现图像所造成的影响在本质上和横向扫描步长误差所造成的影响完全一样；用含有位置搜索的ePIE算法进行图像重建时，轴向距离偏差所造成的影响理论上可以自动得以更正。

Based on the analysis of the axial distance error in the extended ptychographic iterative engine (ePIE), it is pointed out that the influence of the axial distance error to the image quality is equivalent to that of the transverse scanning error. By using the position corrected ePIE algorithm, the image quality degradation induced by the axial distance error can be automatically corrected step by step in the iterative reconstruction.