
This module implements a binomial smoothing filtering\index{filter!binomial}. 
\index{convolution}
It is a Bernouilli filter iterated $N$ times, where
$N$ depends on the standard deviation $S$ and on the weight $W$ 
of the considered pixel~: $N=(2+W)*S^{2}$. 
Let $I$ the input fimage, then the module iterates $N$ times
the following two-steps scheme:

\begin{eqnarray*}
1) && I'_{x,y} \;\longleftarrow\; (I(x-1,y)+I(x+1,y)+W\cdot I(x,y))/(2+W), \\
2) && I'_{x,y} \;\longleftarrow\; (I(x,y-1)+I(x,y+1)+W\cdot I(x,y))/(2+W).
\end{eqnarray*}

