\subsection{Skeleton}

Bastien, our client, is working on the extraction of skeleton from pictures. A skeleton of an object is the elemental structure of it. In this project 2D-skeletons extracted, like in figure \ref{skeletonex}, are defined by a set of vertices and edges. The other group compute with it 2D-skeleton in another format : a set of B-Splines, each of them representing a branch of the skeleton.
B-Splines are given by : the degree of the spline, their control points and the nodes vectors.
The 3D-skeletons are given with 3D B-Splines with the same structure except that the control point are in 3D.
You will find in appendix A \ref{AppendixA} some examples of 2D and 3D skeletons.

\begin{figure}[H]
   \begin{center}
   \includegraphics[scale=0.35]{img/SkeletonEx}
   \caption{\label{skeletonex}Best fitting plane for the set of circles' center points}
   \end{center}
\end{figure}