数字图像傅立叶变换

代码说明：

  数字图像快速傅里叶变换（FFT）。将图像转化成二维灰度图像后再做FFT变换，并输出变换后的幅值图。(Digital image fast Fourier transform (FFT).The image is transformed into a two-dimensional gray level image and then the FFT transformation is made, and the amplitude diagram is output after the transformation.)