Image Smoothing

Mean/Box Filter

Below is an example of mean filter (box filter).

$\frac{1}{9}\left(\begin{array}{ccc}1& 1& 1\\ 1& 1& 1\\ 1& 1& 1\end{array}\right)$

Gaussian blur

Below is an example of Gaussian blur with $\mathrm{\sigma }=1$.

$\frac{1}{4.8976}\left(\begin{array}{ccc}0.3679& 0.6065& 0.3679\\ 0.6065& 1.0000& 0.6065\\ 0.3679& 0.6065& 0.3679\end{array}\right)$

Median filter

Below is an example of median filter. Median filter works best for salt-and-pepper noises.