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Remove artefact using fourier filter

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shubham kumar gupta
shubham kumar gupta on 24 Jun 2022
Answered: Image Analyst on 8 Sep 2022
I have a coin image where mid portion became dark after processing of the data, now i am trying fourier filter to remove artefact, but ig i'm not able to correctly remove artefacts.
My attempt:
function img_back=fftSaft(maxarray)
figure(1);
subplot(2,2,1);
%maxarray=medfilt2(maxarray,[2 2]);
maxarray=imgaussfilt(maxarray,0.8);
maxarray=imsharpen(maxarray);
imshow(maxarray,[]);
af=fftshift(fft2(maxarray));
subplot(2,2,2);
mag=20*log(abs(af));
imshow(mag,[]);
rows=size(maxarray,1); cols = size(maxarray,2);
crow=floor(rows/2);ccol = floor(cols/2);
%af(crow-0.5:crow+0.5, 1:ccol-5) = 0;
%af(crow-0.5:crow+0.5, ccol+6:end) = 0;
af(af>60 & af<150)=0;
subplot(2,2,3);
magnitude_spectrum_no_vertical = 20*log(abs(af));
imshow(magnitude_spectrum_no_vertical,[]);
iaf=ifftshift(af);
img_back=ifft2(iaf);
img_back=real(img_back);
img_back=imsharpen(img_back);
subplot(2,2,4);
imshow(img_back,[]);
end

Answers (1)

Image Analyst
Image Analyst on 8 Sep 2022
Where exactly is the artifact in that image?
I don't know that Fourier filtering could get rid of an artifact such as darkening. You should figure out why your processing made the middle darker in the first place.
If you have any more questions, then attach your original image and code to read it in with the paperclip icon after you read this:

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