# how to smooth the data of array to get a smooth surface?

5 views (last 30 days)
Abdullah on 8 Mar 2023
Commented: William Rose on 9 Mar 2023
how i can remove outliers in data and get a smooth surface?
William Rose on 8 Mar 2023
@Abdullah, Please attach the data as a .mat file.

William Rose on 8 Mar 2023
Check this out:
Or do a median filter, in which each point is replaced by the median of a pxp array centered on that point.

William Rose on 8 Mar 2023
@Abdullah, an example of a median filter for a surface:
First, make a surface with some "noise":
A=repmat(-(-20:20).^2/400,31,1)+repmat([-(-15:15).^2/225]',1,41)+2+(rand(31,41)>.95)/5;
mesh(-20:20,-15:15,A) %display the surface
Filter it with a pxp median filter
p=5; p2=floor(p/2); [n,m]=size(A);
B=zeros(n,m); %allocate array for smoothed surface
for i=1+p2:n-p2
for j=1+p2:m-p2
B(i,j)=median(median(A(i-p2:i+p2,j-p2:j+p2)));
end
end
mesh(-20:20,-15:15,B) %display the surface
The edges are zeros in my simple code, because, if the filter gets any closer to the edges, it will extend beyond the bounds of the original array, which would cause an error. You could improve this by adapting the filter as needed, when it gets near the edge.
William Rose on 9 Mar 2023
@Abdullah, you;re welcome. Good luck with your work.

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