Plot of the frequency response of the average filter:
$ h(k,l)=\begin{array}{ccc}1& 2 & 1\\ 2 &4 &2 \\ 1 & 2 & 1 \end{array} $
Plot of the frequency response of the average filter:
$ h(k,l)=\begin{array}{ccc}1& 2 & 1\\ 2 &4 &2 \\ 1 & 2 & 1 \end{array} $