what is the wrong in this code?

   clc
  clear all
  close all

lena = imread('eight.tif');
A = fftshift(fft2(lena));
S = imnoise(lena,'Gaussian',0,1);
size(S)
% define spatial filters
h_gauss= fspecial('gaussian', 15, 1.0);
% results after spatial filtering
lena_h_gauss = imfilter(S, h_gauss, 'replicate');
% fourier transformed filters
H_gauss = fftshift(fft2(lena_h_gauss));
size(H_gauss)
% filtering in frequency domain
Lena_H_gauss = S .* H_gauss;
lena_H_gauss = ifft2(ifftshift(Lena_H_gauss));
% print results
subplot(3,3,1); imshow(lena); title('Original Image');
subplot(3,3,2); imshow(lena_h_gauss); title('Gauss-Filtered Image');
subplot(3,3,3); imshow(real(log(Lena)), []);  title('FT (Original Image)');
subplot(3,3,4); imshow(real(log(H_gauss)), []); title('FT (Gauss Filter)');
subplot(3,3,5); imshow(lena_H_gauss);  title('Result FT Gauss');

Answer 1

[Image Analyst]

S is complex and imfilter() doesn't work on complex images. You might have to work on the real and imaginary images one at a time.

Answer 2

[John BG]

Hi Ahmed

this is John BG <mailto:[e-mail] [e-mail]>

1.

it may be that rather than real an imaginary parts, you may consider using the module, with abs

instead of

Lena_H_gauss = S .* H_gauss;

use

lena_H_gauss = S .* uint64(abs(H_gauss));

2.

there are

lena_h_gauss

and

Lena_h_gauss

probably only one should be used

3.

also, instead of

subplot(3,3,1); imshow(lena); title('Original Image');
subplot(3,3,2); imshow(lena_h_gauss); title('Gauss-Filtered Image');
subplot(3,3,3); imshow(real(log(Lena)), []);  title('FT (Original Image)');
subplot(3,3,4); imshow(real(log(H_gauss)), []); title('FT (Gauss Filter)');
subplot(3,3,5); imshow(lena_H_gauss);  title('Result FT Gauss');

use

subplot(3,3,1); imshow(lena); title('Original Image');
subplot(3,3,2); imshow(lena_h_gauss); title('Gauss-Filtered Image');
subplot(3,3,3); imshow(real(log(double(lena))), []);  title('FT (Original Image)');
subplot(3,3,4); imshow(real(log(double(H_gauss))), []); title('FT (Gauss Filter)');
subplot(3,3,5); imshow(lena_H_gauss);  title('Result FT Gauss');

.

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

[Ahmed Grera]

Hi Jhon

There is still an error going on

lena_H_gauss = S .* uint64(abs(H_gauss));