\documentclass{article}
\usepackage{amsmath,latexsym,amssymb}
\usepackage{color,graphicx}

\begin{document}
\begin{center}
\setlength{\unitlength}{1cm}
\begin{picture}(-10,-10)
\put(-5,-1.2){$\mathcal{U}$}
\put(-4.25,-1.2){$\mathcal{U'}$}
\put(-10,-10){\includegraphics[height=10cm]{darboux.eps}}
\end{picture}
\end{center}
\end{document}