X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=doc%2Fctsim-concepts.tex;h=bacfd4b4807969b66469c0833c9c682d08ee9c02;hb=7df269f65639c1a862a58649c48331824029128a;hp=27d342a33b72062f926b846809afc8a727379829;hpb=fd5767a661183c8fd4197accc0e9eef3fb5474bc;p=ctsim.git

diff --git a/doc/ctsim-concepts.tex b/doc/ctsim-concepts.tex
index 27d342a..bacfd4b 100644
--- a/doc/ctsim-concepts.tex
+++ b/doc/ctsim-concepts.tex
@@ -2,7 +2,7 @@
 \setheader{{\it CHAPTER \thechapter}}{}{}{\ctsimheadtitle}{}{{\it CHAPTER \thechapter}}
 \ctsimfooter
 
-\section{Overview}\index{Conceptual overview}
+\section{Conceptual Overview}\index{Conceptual overview}
 The operation of \ctsim\ begins with the phantom object.  A
 phantom object consists of geometric elements.  A scanner is
 specified and the collection of x-ray data, or projections, is
@@ -18,7 +18,6 @@ concerned with are the \helprefn{phantom}{conceptphantom} and the
 \helprefn{scanner}{conceptscanner}.
 
 \section{Phantoms}\label{conceptphantom}
-\subsection{Overview}\label{phantomoverview}\index{Phantom!Overview}%
 
 \ctsim\ uses geometrical objects to describe the object being
 scanned. A phantom is composed of one or more phantom elements.
@@ -63,12 +62,12 @@ Of note, the commonly used phantom described by
 Shepp and Logan\cite{SHEPP74} uses only ellipses.
 
 \subsubsection{rectangle}
-Rectangles use \texttt{cx} and \texttt{cy} to define the position of
+Rectangles use \texttt{(cx,cy)} to define the position of
 the center of the rectangle with respect to the origin.  \texttt{dx}
 and \texttt{dy} are the half-width and half-height of the rectangle.
 
 \subsubsection{triangle}
-Triangles are drawn with the center of the base at \texttt{(cx,cy)
+Triangles are drawn with the center of the base at \texttt{(cx,cy)}
 and a base half-width of \texttt{dx} and a height of \texttt{dy}.
 Rotations are then applied about the center of the base.
 
@@ -100,7 +99,6 @@ defined as a rectangle of size 0.1 by 0.1, the phantom size is
 0.101 in each direction.
 
 \section{Scanner}\label{conceptscanner}\index{Scanner!Concepts}%
-\subsection{Dimensions}
 Understanding the scanning geometry is the most complicated aspect of
 using \ctsim. For real-world CT simulators, this is actually quite
 simple. The geometry is fixed by the manufacturer during the
@@ -108,6 +106,7 @@ construction of the scanner and can not be changed. \ctsim,
 being a very flexible simulator, gives tremendous options in
 setting up the geometry for a scan.
 
+\subsection{Dimensions}
 The geometry for a scan starts with the size of
 the phantom being scanned. This is because \ctsim\ allows for
 statistical comparisons between the original phantom image and
@@ -212,7 +211,6 @@ significant distortions will occur.
 
 \subsection{Divergent Geometries}\label{geometrydivergent}\index{Equilinear geometry}\index{Equiangular geometry}
 \index{Scanner!Equilinear}\index{Scanner!Equiangular}
-\subsubsection{Overview}
 For both equilinear (second generation) and equiangular
 (third, fourth, and fifth generation) geometries,
 the x-ray beams diverge from a single source to a detector array.
@@ -303,7 +301,7 @@ length}. This length,
 \latexonly{\begin{equation} d_l = 4\,f \tan (\alpha / 2)\end{equation}}
 \latexignore{\\\centerline{\emph{4 x F x tan(\alpha/2)}}}
 \latexonly{This geometry is shown in figure~\ref{equilinearfig}.}
-\begin{figure}\label{equilinearfig}
+\begin{figure}
 \centerline{\image{10cm;0cm}{equilinear.eps}}
 \latexonly{\caption{\label{equilinearfig} Equilinear geometry}}
 \end{figure}
@@ -318,7 +316,7 @@ accurate as filtered backprojection. This is due primarily
 to interpolation occurring in the frequency domain rather than the
 spatial domain.
 
-\subsection{Filtered Backprojection}\index{Filtered backprojection}
+\subsection{Filtered Backprojection}\index{Filtered backprojection}\index{Symmetric multiprocessing}\index{SMP}
 The technique is comprised of two sequential steps:
 filtering projections followed by backprojecting the filtered projections. Though
 these two steps are sequential, each view position can be processed independently.
@@ -326,9 +324,18 @@ these two steps are sequential, each view position can be processed independentl
 \subsubsection{Parallel Computer Processing}\index{Parallel processing}
 Since each view can be processed independently, filtered backprojection is amendable to
 parallel processing. Indeed, this has been used in commercial scanners to speed reconstruction.
-This parallelism is exploited in the MPI versions of \ctsim\ where the
-data from all the views are spread about amongst all of the
-processors. This has been testing in a cluster of 16 computers with excellent
+This parallelism is exploited both in the \ctsim\ graphical shell and
+in the \helpref{LAM}{ctsimtextlam} version of \ctsimtext. \ctsim\ can distribute it's workload
+amongst multiple processors working in parallel.
+
+The graphical shell will automatically take advantage of multiple CPU's when
+running on a \emph{Symmetric Multiprocessing}
+computer. Dual-CPU computers are commonly available which provide a near doubling
+in reconstruction speeds. \ctsim, though, has no limits on the number of CPU's
+that can be used in parallel. The \emph{LAM} version
+of \ctsimtext\ is designed to work in a cluster of computers.
+This has been testing with a cluster of 16 computers in a
+\urlref{Beowulf-class}{http://www.beowulf.org} cluster with excellent
 results.
 
 \subsubsection{Filter projections}
@@ -359,10 +366,10 @@ by \ctsim. They are taken from the standard measurements used by
 Herman\cite{HERMAN80}. They are:
 
 \begin{itemize}\itemsep=0pt
-\item[-]\textbf{$d$}\quad The normalized root mean squared distance measure.
-\item[-]\textbf{$r$}\quad The normalized mean absolute distance measure.
-\item[-]\textbf{$e$}\quad The worst case distance measure over a \latexonly{$2\times2$}\latexignore{\emph{2 x 2}} pixel area.
-\end{twocollist}
+\item[]\textbf{$d$}\quad The normalized root mean squared distance measure.
+\item[]\textbf{$r$}\quad The normalized mean absolute distance measure.
+\item[]\textbf{$e$}\quad The worst case distance measure over a \latexonly{$2\times2$}\latexignore{\emph{2 x 2}} pixel area.
+\end{itemize}
 
 These measurements are defined in equations \ref{dequation} through \ref{bigrequation}.
 In these equations, $p$ denotes the phantom image, $r$ denotes the reconstruction