function erms=jfwucha(f1,f2)
e=double(f1)-double(f2);
[m,n]=size(e);
erms=sqrt(sum(e(:).^2)/(m*n));
if erms~=0
    emax=max(abs(e(:)));
    [h,x]=hist(e(:));
    if length(h)>=1
        figure(4);
        bar(x,h,'K');
        e=mat2gray(e,[-emax,emax]);
        figure(5);
        imshow(e);
    end
end