Remove noise from the image

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shubham kumar gupta
shubham kumar gupta on 23 May 2022
Edited: shubham kumar gupta on 23 May 2022
I have a image of a coin I wanted to make a circular mask to remove noise [Attached mat]
I tried using imfindcircle but it is not working properly

Answers (1)

Bjorn Gustavsson
Bjorn Gustavsson on 23 May 2022
First start by trying standard filtering-methods. Compare what you get with 2-D median-filter (medfilt2), and Lee's sigma-filter (wiener2) and see how they perform. After doing that you can check different more advanced image-filters on the file-exchange, for example: bilateral filters, Nonlinear Diffusion filters, total variation filtering and on and on. But first use the basic tools then understand their use and the noise-characteristics in your image. Check the help and documentation to medfilt2 and wiener2.
HTH
  3 Comments
shubham kumar gupta
shubham kumar gupta on 23 May 2022
Its a tilted coin of 180 radius centers not properly known
I tried this first
r=180x_c=180+17;y_c=180+5;
%generate a coordinate grid
[y,x]=ndgrid(0:401,0:401);
%perform calculation
paper= (x-x_c).^2+(y-y_c).^2 <= r^2;
%show result
figure,imshow(paper); %show masked image
for i=1:401
for j=1:401
if paper(i,j)<1
d(i,j)=paper(i,j)*d(i,j);
end
end
end
figure,mesh(d)
rest i'm trying to remove

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