Harmonic mean filter

% Harmonic mean filter
% Read a gray scale image and add a noise to it and filter it using
% Harmonic mean filter.
clear all; close all; clc;
f = imread('cameraman.tif');
f = imnoise(f,'gaussian',0,0.02);
f = im2double(f);
subplot(1,2,1),imshow(f),title('Original Image');

[m n]=size(f);
si=1;
for i = 1:m
for j = 1:n
con=0; s1=0;
for k1 = i-si:i+si
for p1 = j-si:j+si
if ((k1 > 0 && p1 > 0) && (k1 < m && p1 < n))
con = con+1;
if f(k1,p1)==0
s1 = s1+0;
else
s1=s1+(1/f(k1,p1));
end
end
end
end
b1(i,j)=con/s1;
end
end
subplot(1,2,2),imshow(b1),title('Harmonic mean filtered');