An improved method is put forward, in which the equation, computation domain and boundary condition are changed, and then the phase is reconstructed by the multigrid method and corrected at last.

• 为了克服上述困难,提出了一种相位恢复的改进方法,即改变了方程的表示形式、计算区域和边界条件,并用多重网格法进行求解获得重构相位,最后再将其修正。