teste01.m

Gradient code. Use this to do gradient of image.

clc;

clear all;
image = imread('lena512.bmp');

image_t = image';
gx = diff(image);
gy = diff(image_t);
hx = diff(gx);
hy = diff(gy);
mlg = min(size(gx));
mll = min(size(hx));
image_gradient = abs(gx(1:mlg,1:mlg))+abs(gy(1:mlg,1:mlg));
FG = fft2(image_gradient,512,512);
FG2 = fftshift(FG);
figure;
imshow(double(FG2));

F = fft2(image,512,512);
F2 = fftshift(F);
z = size(F2);
second = zeros(z(1),z(2));
for u = 1:z(2)
   for v = 1:z(1)
      second(u,v) = j.*(u+v).*F2(u,v)/(z(1));
   end 
end
figure;
imshow(double(second));
im1 = real(ifft2(FG2));
im2 = real(ifft2(second));
figure;
imshow(double(im1));
figure;
imshow(double(im2));