\chapter{The Web Interface}\label{webinterface}\index{Web interface}%
\setheader{{\it CHAPTER \thechapter}}{}{}{\ctsimheadtitle}{}{{\it CHAPTER \thechapter}}%
\ctsimfooter%

\section{Overview}
\ctsim\ can also be executed via a web browser. The Perl program
\texttt{ctsim.cgi} takes projections of a standard phantom object,
performs reconstruction, and then compares the rasterized phantom
object with the reconstruction. The comparison is performed both
visually by an image subtraction as well as by statistical
analysis.

The \texttt{ctsim.cgi} program is invoked from the HTML file
\texttt{simulate.html}.

\section{Requirements}
   \begin{itemize}\itemsep=0pt
      \item \urlref{Apache}{http://www.apache.org} or other CGI-compatible web server

      \item Perl (version 4.0 or higher)

      \item A client web browser than can display PNG files. Most
      current web browsers support PNG.

      \item A knowledgable system administrator.
\end{itemize}

\section{Installation}
Installation is rather automatic on Linux and UNIX systems. The
\texttt{configure} script needs to be given options that specify
the directory for web pages and for CGI programs.
