I = imread('medlines.gif');       	%read in a test image
I = imnoise(I, 'salt & pepper');
figure(1); imshow(I, [])
dim = size(I);	%get the size, store it in a 1x2 array
J = zeros(dim+4);	 %make a new image 4 pixels wider and taller than I
J(3:dim(1)+2,3:dim(2)+2) = I;	 %stick I in the middle of J ( we now have I padded with a 2 pixel border)


J(:,1) = J(:,4);		%take care of padding our extra 4 columns	
J(:,2) = J(:,3);
J(:,dim(2)+3) = J(:,dim(2)+2);
J(:,dim(2)+4) = J(:,dim(2)+1);

J(1,:) = J(4,:);		%take care of padding our extra 4 rows
J(2,:) = J(3,:);
J(dim(1)+3,:) = J(dim(1),:);
J(dim(1)+4,:) = J(dim(1)-1,:);

K = MedianFilter(J);	            %pass our padded image to the MEX routine
K = K(3:dim(1)+2,3:dim(2)+2);	%throw away the padding 
figure(2); imshow(K,[0 255]);	% show it
	
clear mex	%useful for debugging. Otherwise Matlab won’t let go of 
                        % the DLL and
    			%Visual Studio can’t compile