：i1=imread('C:\Users\Administrator\Desktop\图像处理\T1.JPG'); i1=double(i1)/255; figure(1) imshow(i1);title('原图'); i2=fft2(i1); figure(2) imshow(i2);title('傅里叶变换后'); if size(i1, 3) > 1 G = im2double(rgb2gray(i1)); else G = im2double(i1); end im3= fftshift(fft2(G)); i3=log10(abs(im3