gradfourier.m

Gradient code. Use this to do gradient of image.

clc;
close all;
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));
image_lap = abs(hx(1:mll,1:mll))+abs(hy(1:mll,1:mll));
figure;
imshow(image_gradient);
image_fourier = fftshift(fft2(image));
der_image_fourier = zeros(length(image_fourier),length(image_fourier));

for u = 1:length(image_fourier)
  for v = 1:length(image_fourier)
    der_image_fourier(u,v) = j.*(u+v).*image_fourier(u,v);
  end
end
figure;
imshow(double(image_fourier));
figure;
imshow(ifft2(double(der_image_fourier)));