what is the wrong in this code?

Question

Ahmed Grera 2017-9-5

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355333-what-is-the-wrong-in-this-code

评论： Ahmed Grera 2017-9-6

   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');

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Answer 1

Image Analyst 2017-9-5

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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.

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Answer 2

John BG 2017-9-6

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/355333-what-is-the-wrong-in-this-code#answer_280406

编辑：John BG 2017-9-6

在 MATLAB Online 中打开

Hi Ahmed

this is John BG <mailto:jgb2012@sky.com jgb2012@sky.com>

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');