\chapter{Introduction}

\section{Basic assumptions}

For now I am going to assume that anyone reading this has a fair idea of what
high dynamic range images are, and how to produce them.

\section{So what's all this then?}

\tt{STM} is a collection of tools for processing pictures, with an emphasis on
so called "high dynamic range", or HDR images.  It includes a number of tools 
for tone mapping, contrast manipulation and special effects.

\subsection{History \& Motivation}

You might want to skip this.

In the dim and distant past I was researching tone mapping algorithms for a toy
ray tracer I had developed.  It became apparent that none of the algorithms 
available were ideal in all cases, although many of them have good features.
This was particularly true of "local" tone mapping algorithms.

Fortunately a number of local tone mapping algorithme can be broken down into
parts that are almost interchangeable, so why not combine the best bits of 
all of them?

It might even be possible to combine the worst bits\ldots

\subsection{Overall design}

The software consists of a number of \emph{processors}, which convert one or 
more images into a new output image.  The output of a processor can be 
connected to the input of another, allowing a great deal of flexibility and
control over results.

The main drawbacks of this approach are that it tends to use more memory than
editing an image "in place", and complex time consuming processes are poorly 
suited to interactive preview.

\section{Useful software}

STM does not currently include any image merging or creation tools.  Providing 
such capabilities is a fairly low priority at the moment, as there are already
a number of very capable tools available.

A short and far from exhaustive list is given below:

\begin{itemize}
    \item MacOS-X
    \begin{itemize}
        \item Photoshop.  HDR creation, tone mapping and editing.  Commercial.
        \item Photosphere. HDR image and panorama creation, with some tone 
              mapping.  Free, closed source.
    \end{itemize}
    \item Linux
    \begin{itemize}
         \item Qtpfsgui. HDR image creation and tone mapping.  Free, open
               source.
         \item Hugin. HDR image and panorama creation.  Free, open source.
    \end{itemize}
    \item Windows
    \begin{itemize}
        \item Photoshop.  HDR creation, tone mapping and editing.  Commercial.
        \item Photomatix. HDR image creation and tone mapping.  Commercial.
        \item Picturenaut. HDR image creation and tone mapping.  Free, closed 
              source.
    \end{itemize}
\end{itemize}


