low pass filter for image analysis

Question

Snowleopard 2016-9-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/303358-low-pass-filter-for-image-analysis

评论： Snowleopard 2016-9-24

I am doing low pass filtering of an image.After applying mask and I need to get filtered image but instead I am getting I6 as attached. I have tried with different mask sizes but still unable to get the same image back with low frequency content. Can you plz check the code and point the mistake in code or methodology.

Thanks in advance,

if true
  % code
clc
close all
clear all
I1 = imread('C:\User\Desktop\taken\s3.jpg');
I1 = imresize(I1,[128 128]);
I2 = rgb2gray(I1)
I2=double(I2);
figure, imshow(uint8(I2));
I3=fft2(I2);
I3=fftshift(I3);
figure
I4=log(1+abs(I3));
imshow(mat2gray(I4));
[r,c]=size(I2);
orgr=r/2;
orgc=c/2;
mf= zeros(r,c);
D0= 40;
for i=1:r
  for j=1:c
      if((i-orgr)^2+(j-orgc)^2)^(0.5)<=D0
          mf(i,j)=1;
      end
  end
end
figure
imshow(uint8(255*mf));
title('frequency domain filter used');
I5=I3*mf;
figure,
I4=log(1+abs(I5));
imshow(mat2gray(I4));
title('filtered image in frequency domain');
I6=ifft2(ifftshift(I5));
figure,
imshow(uint8(abs(I6)));
title('filtered gray scale image');
end