This module maps in the output cimage $J$ the junctions found in 
the input cimage $U$ : if the point $(x,y)$ is a junction, the
value of $J(x,y)$ will be $255$ and $0$ elsewhere.
The module returns the number of junctions found.
For a description of the junction detection 
algorithm\index{junction detector}, please
see~\cite{caselles.coll.ea:kanizsa},\cite{caselles.coll.ea:topographic} 
and~\cite{froment:functional}.

The option \verb+-a+ allows to choose the area threshold associated
to the detection, while the option \verb+-q+ is related to the quantization 
threshold. Those thresholds are used to avoid false detections.

