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高分辨率电子显微学中相位复原问题是一个重要问题。本文的计算表明,对于振幅为常数或线性函数,相位为抛物型、正弦型或指数型的波函数,可以采用Gerchberg-Saxton迭代算法从已知的象面和衍射面上的强度分布来唯一地和精确地复原真实的相位。我们编制了计算机程序,对于给定的象面波函数,采用离散的快速傅里叶算法,可以计算其衍射面的波函数。输入数值在-π,+π间的初始相位后,按照G-S迭代算法,利用本程序可以复原相位。文中详细给出了若干个计算实例。所得的相位迭代解对于1弧度的初始相位扰动是稳定的。The problem of phase retrieval from image and diffraction patterns is of importance in electron microscopy. In this paper the true phase can be extracted uniquely and accurately by Gerchberg-Saxton iterative algorithm for the wave function, its amplitude being unity or a linear function, while its phase being a parabolic, sinuous or exponential function.A computer program for retrieving the phase has been worked out. As an image wave function is given, its Fourier transform may be calculated by the discrete fast Fourier transform algorithm. So we can recover the phase with G-S algorithm, using a random initial phase between -π and +π. The numerical examples are given in detail. The phase retrieval solution is stable under fluctuation of input initial phase up to 1 rad.
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