This paper describes the program block diagram of medical image filtering based on fft.

imread reads the original image-"fft2 carries out two-dimensional discrete Fourier transform on the two-dimensional image-"fft2 shift carries out shift on the Fourier-transformed image-"self-written filter filters the image in frequency domain-"inverse Fourier transform (there are many details that need to be paid attention to in this step, which I forgot for a long time)-"imwrite writes the processed image.