Add fig caption that was missing

pcprocessing/pcprocessing.tex

@@ -330,7 +330,7 @@ \subsection{Cloth simulation filter (CSF) algorithm}
 \begin{marginfigure}
   \centering
   \includegraphics[width=\linewidth]{csf_2cases}
-  \caption{}%
+  \caption{Internal forces in the CSF algorithm: 2 cases are possible.}%
 \label{fig:csf_2cases}
 \end{marginfigure}
 \begin{enumerate}