This module is mainly an auxiliary module for
\verb+km_match_si+ and \verb+km_match_ai+. It
computes all pairs of curves that are good candidates to match
(pre-matchings). However, it can be used independently from
these modules.

\verb+dict1+ and \verb+dict2+ contain $N_1$ and $N_2$ normalized codes
of pieces of curves of images 1 and 2. To be more precise,
\verb+dict1+ $=\{{\mathcal C}^1_i, 0 \leq i \leq N_1-1 \}$ and
\verb+dict2+ $=\{{\mathcal C}^2_j, 0 \leq j \leq N_2-1 \}$.  Both
dictionaries must have been computed using the same MegaWave module
(\verb+km_createdict_si+ or \verb+km_createdict_ai+).

\verb+km_prematchings+ returns an \verb+Flists+ that containts $N_1$
\verb+Flist+. The $i$-th \verb+Flist+ contains the indices $j$ of all
the codes of \verb+dict2+ that satisfy 
$d_H({\mathcal C}^1_i,{\mathcal C}^2_j) < $ \verb+maxError+, 
where $d_H$ is the Hausdorff distance. 

It should be noted that \verb+maxError+ is a distance between
normalized codes and not a distance between curves in the image frame,
and typically its value is to be chosen in the range $[0.1,0.3]$.

\medskip

For more details, see J.-L. Lisani's PhD dissertation~\cite{lisani:comparaison} 
or~\cite{lisani.monasse.ea:on}.
