X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=doc%2Fctsim-concepts.tex;fp=doc%2Fctsim-concepts.tex;h=27d342a33b72062f926b846809afc8a727379829;hb=fd5767a661183c8fd4197accc0e9eef3fb5474bc;hp=63d478c20ae2bae6e15a4f508efcd64ed4ae25a0;hpb=07353e6f00d4b1b0c7a9b57b9b42043da29489ba;p=ctsim.git diff --git a/doc/ctsim-concepts.tex b/doc/ctsim-concepts.tex index 63d478c..27d342a 100644 --- a/doc/ctsim-concepts.tex +++ b/doc/ctsim-concepts.tex @@ -6,7 +6,7 @@ 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 -simulated. That projection data can be reconstructed using various +simulated. This projection data can be reconstructed using various user-controlled algorithms producing an image of the phantom object. These reconstructions can be visually and statistically compared to the original phantom object. @@ -58,7 +58,7 @@ meanings depending on the element type. \subsubsection{ellipse} Ellipses use \texttt{dx} and \texttt{dy} to define the semi-major and -semi-minor axis lengths, with the center of the ellipse at \texttt{(cx,cy)}. +semi-minor axis lengths with the center of the ellipse at \texttt{(cx,cy)}. Of note, the commonly used phantom described by Shepp and Logan\cite{SHEPP74} uses only ellipses. @@ -68,8 +68,8 @@ 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)}, -with a base half-width of \texttt{dx} and a height of \texttt{dy}. +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. \subsubsection{segment} @@ -108,7 +108,7 @@ 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. -In general, the geometry for a scan all starts with the size of +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 it's reconstructions. Since CT scanners scan a circular area, the @@ -358,10 +358,10 @@ Images can be compared statistically. Three measurements can be calculated by \ctsim. They are taken from the standard measurements used by Herman\cite{HERMAN80}. They are: -\begin{twocollist} -\twocolitem{\textbf{$d$}}{The normalized root mean squared distance measure.} -\twocolitem{\textbf{$r$}}{The normalized mean absolute distance measure.} -\twocolitem{\textbf{$e$}}{The worst case distance measure over a \latexonly{$2\times2$}\latexignore{\emph{2 x 2}} pixel area.} +\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} These measurements are defined in equations \ref{dequation} through \ref{bigrequation}.