中文说明：本程序采用菲涅尔衍射计算公式的S-FFT形式实现基本的衍射计算，通过调入一幅图像，先对其进行傅里叶变换，之后乘上相位信息。可以通过对程序的改写实现D-FFT与T-FFT，三种计算的衍射距离均会有不同取值。
English Description：
This program implemented by Fresnel diffraction formula of S-FFT diffraction, by calling into one image, its Fourier transform, then ride on phase information. Can be realized through the rewriting of procedures D-FFT and T-FFT, three methods to calculate the diffraction distance will have different values.