This module uniformly quantifies a fimage $A$ on $M$ gray levels,
using the following scheme :

Let be $a$ the minimum value of $A$ and $b$ the maximum value.
Then we set 
\[\left. \begin{array}{l}
\delta = \frac{b-a}{M} \\
\; \mbox{and} \\ 
\forall r = 
0,1, \ldots, M-1, \, \forall (x,y) \\
\; \mbox{if} \\
a + r \delta \leq A(x,y) < a + (r+1)\delta \\
\; \mbox{then set} \\
Q(x,y) = a + r\delta + \frac{\delta}{2} \mbox{ (without option {\tt -l})}\\
\; \mbox{or} \\
Q(x,y) = a + r\delta \mbox{ (with option {\tt -l})}\\
\end{array} \right.\]
The last inequality being not strict when $r = M-1$.

The module returns the value of $\delta$.

