Adaptive localnoisereduction filter

clear all; close all; clc;
f = imread('cameraman.tif');
f = im2double(f);
[m n]=size(f);
f1=zeros(m,n);
f = imnoise(f,'gaussian',0,0.1);
D = std2(f);
M = mean2(f);
for i=3:m-2
for j=3:n-2
con=0; s=0; s1=0;
for k=i-2:i+2
for p=j-2:j+2
con=con+1;
s = s+f(k,p);
s1(con)=f(k,p);
end
end
lm=s/con;
ld = std(s1);
if ld >0
f1(i,j) = f(i,j)-((D*(f(i,j)-lm)/ld));
else
f1(i,j) = f(i,j)-0;
end
end
end
figure,imshow(f);
figure,imshow(f1);