-\chapter{Concepts}\index{Concepts}%
-\setheader{{\it CHAPTER \thechapter}}{}{}{\ctsimheadtitle}{}{{\it CHAPTER \thechapter}}%
-\ctsimfooter%
+\chapter{Concepts}
+\setheader{{\it CHAPTER \thechapter}}{}{}{\ctsimheadtitle}{}{{\it CHAPTER \thechapter}}
+\ctsimfooter
-\section{Overview}\label{conceptoverview}\index{Conceptual Overview}%
+\section{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
In order to use \ctsim\ effectively, some knowledge of how
\ctsim\ works and the approach taken is required. \ctsim\ deals with a
variety of object, but the two primary objects that we need to be
-concerned with are the \emph{phantom} and the \emph{scanner}.
+concerned with are the \helprefn{phantom}{conceptphantom} and the
+\helprefn{scanner}{conceptscanner}.
\section{Phantoms}\label{conceptphantom}
-\subsection{Overview}\label{phantomoverview}\index{Phantom Overview}%
+\subsection{Overview}\label{phantomoverview}\index{Phantom!Overview}%
\ctsim\ uses geometrical objects to describe the object being
-scanned. A phantom is composed a one or more phantom elements.
+scanned. A phantom is composed of one or more phantom elements.
These elements are simple geometric shapes, specifically,
rectangles, triangles, ellipses, sectors and segments. With these
elements, the standard phantoms used in the CT literature can be
The types of phantom elements and their definitions are taken with
permission from G.T. Herman's 1980 book\cite{HERMAN80}.
-\subsection{Phantom File}\label{phantomfile}\index{Phantom file syntax}
+\subsection{Phantom File}\label{phantomfile}\index{Phantom!File syntax}
Each line in the text file describes an element of the
phantom. Each line contains seven entries, in the following form:
\begin{verbatim}
element-type cx cy dx dy r a
\end{verbatim}
The first entry defines the type of the element, either
-\rtfsp\texttt{rectangle}, \texttt{ellipse}, \texttt{triangle},
-\rtfsp\texttt{sector}, or \texttt{segment}. \texttt{cx},
-\rtfsp\texttt{cy}, \texttt{dx} and \texttt{dy} have different
+\texttt{rectangle}, \texttt{ellipse}, \texttt{triangle},
+\texttt{sector}, or \texttt{segment}. \texttt{cx},
+\texttt{cy}, \texttt{dx} and \texttt{dy} have different
meanings depending on the element type.
-\rtfsp\texttt{r} is the rotation applied to the object in degrees
-counterclockwise, and \texttt{a} is the X-ray attenuation
+For all phantom elements, \texttt{r} is the rotation applied to the object in degrees
+counterclockwise and \texttt{a} is the X-ray attenuation
coefficient of the object. Where objects overlap, the attenuations
of the overlapped objects are summed.
-\subsection{Phantom Elements}\label{phantomelements}\index{Phantom elements}
+\subsection{Phantom Elements}\label{phantomelements}\index{Phantom!Elements}
\subsubsection{ellipse}
Ellipses use \texttt{dx} and \texttt{dy} to define the semi-major and
below the x-axis. The sector is then rotated and translated the
same as a segment.
-\subsection{Phantom Size}\index{Phantom size}
+\subsection{Phantom Size}\index{Phantom!Size}
The overall dimensions of the phantom are increased by 1\% above the
specified sizes to avoid clipping due to round-off errors from
sampling the polygons of the phantom elements. So, if the phantom is
-defined as a rectangle of size 0.1 by 0.1, the actual phantom has
-extent 0.101 in each direction.
+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}%
+\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
-construction of the scanner and can not be changed. Conversely,
-real-world CT scanners can only take objects up to a fixed size.
-
-\ctsim, being a very flexible simulator,
-gives tremendous options in setting up the geometry for a scan.
+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 phantom being scanned. This is because \ctsim\ allows for
The other important geometry variables for scanning phantoms are
the \emph{view diameter}, \emph{scan diameter}, and \emph{focal
-length}. These variables are all input into \ctsim\ in terms of
+length}. These variables are input into \ctsim\ in terms of
ratios rather than absolute values.
-\subsubsection{Phantom Diameter}\index{Phantom diameter}
+\subsubsection{Phantom Diameter}\index{Phantom!Diameter}
\begin{figure}
$$\image{5cm;0cm}{scangeometry.eps}$$
\caption{\label{phantomgeomfig} Phantom Geometry}
height is used to define the square that completely surrounds the
phantom. Let \latexonly{$p_l$}\latexignore{\emph{Pl}} be the width
and height of this square. The diameter of this boundary box,
-\latexonly{$p_d$,}\latexignore{\emph{Pd},} is then
+\latexonly{$p_d$,}\latexignore{\emph{Pd},} is given by the
+Pythagorean theorem and is
\latexignore{\\\centerline{\emph{Pl x sqrt(2)}}\\}
\latexonly{\begin{equation}p_d = p_l \sqrt{2}\end{equation}}
-CT scanners actually collect projections around a
-circle rather than a square. The diameter of this circle is also
+CT scanners collect projections around a
+circle rather than a square. The diameter of this circle is
the diameter of the boundary square \latexonly{$p_d$. These
relationships are diagrammed in figure~\ref{phantomgeomfig}.}
\latexignore{emph{Pd}.}
\subsubsection{View Diameter}\index{View diameter}
The \emph{view diameter} is the area that is being processed
during scanning of phantoms as well as during rasterization of
-phantoms. By default, the \emph{view diameter} \rtfsp is set equal
+phantoms. By default, the \emph{view diameter} is set equal
to the \emph{phantom diameter}. It may be useful, especially for
experimental reasons, to process an area larger (and maybe even
smaller) than the phantom. Thus, during rasterization or during
experimental purposes, it may be desirable to scan an area either
larger or smaller than the \emph{view diameter}. Thus, the concept
of \emph{scan ratio}, \latexonly{$s_r$,}\latexignore{\emph{SR},}
-is arises. The scan diameter
-\latexonly{$s_d$}\latexignore{\emph{Sd}} is the diameter over
+is arises. The scan diameter,
+\latexonly{$s_d$,}\latexignore{\emph{Sd},} is the diameter over
which x-rays are collected and is defined as
\latexonly{\begin{equation}s_d =v_d s_r\end{equation}}
\latexignore{\\\centerline{\emph{Sd = Vd x SR}}\\}
source inside of the \emph{view diameter}.
-\subsection{Parallel Geometry}\label{geometryparallel}\index{Parallel Geometry}
+\subsection{Parallel Geometry}\label{geometryparallel}\index{Parallel geometry}
The simplest geometry, parallel, was used in \mbox{$1^{st}$} generation
scanners. As mentioned above, the focal length is not used in this simple
significant distortions will occur.
-\subsection{Divergent Geometries}\label{geometrydivergent}\index{Divergent geometry}
+\subsection{Divergent Geometries}\label{geometrydivergent}\index{Equilinear geometry}\index{Equiangular geometry}
\subsubsection{Overview}
Next consider the case of equilinear (second generation) and equiangular
(third, fourth, and fifth generation) geometries. In these cases,
In the equilinear mode, a single
source produces a fan beam which is read by a linear array of detectors. If
the detectors occupy an arc of a circle, then the geometry is equiangular.
-\latexonly{The configurations are shown in figure~\ref{divergentfig}.}
+\latexonly{These configurations are shown in figure~\ref{divergentfig}.}
\begin{figure}
\image{10cm;0cm}{divergent.eps}
\caption{\label{divergentfig} Equilinear and equiangular geometries.}
\end{figure}
-\subsubsection{Fan Beam Angle}
+\subsubsection{Fan Beam Angle}\index{Fan beam angle}
For these divergent beam geometries, the \emph{fan beam angle}
needs to be calculated. For real-world CT scanners, this is fixed
at the time of manufacture. \ctsim, however, calculates the
\emph{fan beam angle}, $\alpha$, from the \emph{scan diameter} and
-the \emph{focal length} \latexignore{\\$$\emph{alpha = 2 x asin (
-(Sd / 2) / f)}$$\\}
+the \emph{focal length}:
+\latexignore{\centerline{\emph{alpha = 2 x asin (
+(Sd / 2) / f)}}}
\latexonly{\begin{equation}\label{alphacalc}\alpha = 2 \sin^{-1}
((s_d / 2) / f)\end{equation}
This is illustrated in figure~\ref{alphacalcfig}.}
\latexignore{\\\centerline{\emph{Sd = Sr x Vr x Pd}}\\}
Further, $f$ can be defined as
-\latexonly{\[f = f_r (v_r p_d / 2)\]}
+\latexonly{\begin{equation} = f_r (v_r p_d / 2)\end{equation}}
\latexignore{\\\centerline{\emph{F = FR x (VR x Pd)$$\\}}}
Substituting these equations into \latexignore{the above
\subsubsection{Detector Array Size}
In general, you do not need to be concerned with the detector
-array size. It is automatically calculated by \ctsim. For the
+array size -- it is automatically calculated by \ctsim. For the
particularly interested, this section explains how the detector
array size is calculated.
\section{Reconstruction}\label{conceptreconstruction}\index{Reconstruction Overview}%
\subsection{Direct Inverse Fourier}
-This method is not currently implemented in \ctsim, however it is
+This method is not currently implemented in \ctsim; however, it is
planned for a future release. This method does not give results as
-accurate as filtered backprojection. The difference is due primarily
+accurate as filtered backprojection. This is due primarily
because interpolation occurs in the frequency domain rather than the
spatial domain.
\subsection{Filtered Backprojection}\index{Filtered backprojection}
The technique is comprised of two sequential steps:
-filtering projections and then backprojecting the filtered projections. Though
-these two steps are sequential, each view position can be processed individually.
+filtering projections followed backprojecting the filtered projections. Though
+these two steps are sequential, each view position can be processed independently.
\subsubsection{Multiple Computer 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 16-CPU cluster with excellent
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{description}
-\item[$d$] The normalized root mean squared distance measure.
-\item[$r$] The normalized mean absolute distance measure.
-\item[$e$] The worst case distance measure over a $2\times2$ area.
-\end{description}
+
+\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.}
+\end{twocollist}
These measurements are defined in equations \ref{dequation} through \ref{bigrequation}.
In these equations, $p$ denotes the phantom image, $r$ denotes the reconstruction
-image, and $\bar{p}$ denotes the average pixel value for $p$. Each of the images have a
+image, and $\bar{p}$ denotes the average pixel value of $p$. Each of the images have a
size of $m \times n$. In equation \ref{eequation} $[n/2]$ and $[m/2]$ denote the largest
integers less than $n/2$ and $m/2$, respectively.
%Tex2RTF can not handle the any subscripts or superscripts for the inner summation unless
% have a space character before the \sum
\latexonly{\begin{equation}\label{dequation} d =\sqrt{\frac{\displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{(p_{i,j} - r_{i,j})^2}}}{\displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{(p_{i,j} - \bar{p})^2}}}}\end{equation}}
-\latexonly{\[\label{requation}r = \frac{ \displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{|p_{i,j} - r_{i,j}|}}}{ \displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{|p_{i,j}|}}}\]}
+\latexonly{\begin{equation}\label{requation}r = \frac{ \displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{|p_{i,j} - r_{i,j}|}}}{ \displaystyle \sum_{i=1}^{n}{ \sum_{j=1}^{m}{|p_{i,j}|}}}\end{equation}}
\latexonly{\begin{equation}\label{eequation}e = \max_{1 \le k \le [n/2] \atop 1 \le l \le [m/2]}(|P_{k,l} - R_{k,l}|)\end{equation}}
\latexonly{where}
-\latexonly{\[\label{bigpequation}P_{k,l} = \textstyle \frac{1}{4} (p_{2k,2l} + p_{2k+1,2l} + p_{2k,2l+l} + p_{2k+1,2l+1})\]}
+\latexonly{\begin{equation}\label{bigpequation}P_{k,l} = \textstyle \frac{1}{4} (p_{2k,2l} + p_{2k+1,2l} + p_{2k,2l+l} + p_{2k+1,2l+1})\end{equation}}
\latexonly{\begin{equation}\label{bigrequation}R_{k,l} = \textstyle \frac{1}{4} (r_{2k,2l} + r_{2k+1,2l} + r_{2k,2l+1} + r_{2k+1,2l+1})\end{equation}}
+\begin{comment}
+\end{comment}
\section{Overview}\index{Graphical shell}
-\ctsim\ is the graphical shell for the CTSim project. It utilizes
-using the \urlref{wxWindows}{http://www.wxwindows.org} library for
+\ctsim\ is the graphical shell for the CTSim project. This shell uses
+the \urlref{wxWindows}{http://www.wxwindows.org} library for
cross-platform compatibility. The graphical shell is compatible
with Microsoft Windows, \urlref{GTK}{http://www.gtk.org}, and
\urlref{Motif}{http://www.openmotif.org} graphical environments.
\usage \texttt{ctsim [files to open...]}
You can invoke \ctsim\ by itself on the command line, or include
-on the command-line any number of files that you want \ctsim\ to
+any number of files that you want \ctsim\ to
automatically open. \ctsim\ can open projection files, image
files, phantom files, and plot files.
the creation and modifications of images.
\subsection{Projection}
-Projection files are created from Phantom files during the
+Projection files are created from phantom files during the
projection process. Numerous options are available for the
creation of the these files. The files are stored in a binary
format with cross-platform compatibility on little and big endian
\subsection{Plot}
Plot files are created by \ctsim\ during analysis of image files.
They can be read and stored on the disk. They are stored as ASCII
-files for easy cross-platform support.
+files for easy cross-platform support and editing.
\section{Global Menu Commands}
-These commands are present on the menus of all windows.
+These global commands are present on the menus of all windows.
-\subsection{File - Create Phantom}\index{Create phantom dialog}
+\subsection{File - Create Phantom}\label{IDH_DLG_PHANTOM}\index{Dialog!Create phantom}
This command brings up a dialog box showing the phantoms that are preprogrammed
into \ctsim. After selecting one of these phantoms, the new window with that
phantom will be generated. The preprogrammed phantoms are:
center of the phantom and \texttt{0} everywhere else.}
\end{twocollist}
-\subsection{File - Create Filter}\index{Create filter dialog}
+\subsection{File - Create Filter}\label{IDH_DLG_FILTER}\index{Dialog!Create filter}
This command brings up a dialog box showing the pre-programmed filters
of \ctsim. This command will create a 2-dimensional image of the selected filter.
The center of the filter is at the center of the image.
These filters can be created in their natural frequency domain or in their spatial domain.
+
\begin{twocollist}
\twocolitem{\textbf{Filter}}{Selects the filter to generate.}
\twocolitem{\textbf{Domain}}{Selects either the \texttt{Frequency} or \texttt{Spatial} domains. The filters have the
\twocolitem{\textbf{Hamming Parameter}}{Sets the parameter for the Hamming filter.}
\twocolitem{\textbf{Bandwidth}}{Sets the bandwidth of the filter.}
\twocolitem{\textbf{Axis (input) Scale}}{Sets the scale for the filter input. By default, the input to the filter is
-the distance in pixels from the center of the image. By changing this value, one can set a scale the input to the filter.}
-\twocolitem{\textbf{Filter (output) Scale)}}{Multiplies the output of the filter by this amount. By default, the filter has a maximum
+the distance in pixels from the center of the image. By changing this value, one can set a scale the input to the filter.
+For example, if the output image is \texttt{101} pixels and thus the center of the image is at \texttt{(50,50)}, then a pixel
+lying at point \texttt{100,50} would be 50 units from the center of the filter. By applying an \texttt{Axis scale} of
+\texttt{0.1}, then that point would be scaled to 5 units from the center of the filter.}
+\twocolitem{\textbf{Filter (output) Scale}}{Multiplies the output of the filter by this amount. By default, the filter has a maximum
value of \texttt{1}.}
\end{twocollist}
-\subsection{File - Preferences}\index{Preferences}
+\subsection{File - Preferences}\label{IDH_DLG_PREFERENCES}\index{Dialog!Preferences}
This command displays a dialog box that allows users to control
the behavior of \ctsim. These options are saved across \ctsim\ sessions.
Under Microsoft Windows environments, they are stored in the registry.
-On UNIX and Linux environments, they are stored in the users home
+On UNIX and Linux environments, they are stored in the user's home
directory with the filename of \texttt{.ctsim}.
\begin{twocollist}
\item A list of all component phantom elements
\end{itemize}
-\subsection{Rasterize Dialog}\index{Rasterize}
+\subsection{Rasterize Dialog}\label{IDH_DLG_RASTERIZE}\index{Dialog!Rasterize}
This creates an image file from a phantom. Technically, it
converts the phantom from a vector (infinite resolution) object
into a 2-dimension array of floating-point pixels. The parameters
to set are:
\begin{twocollist}
-\twocolitemruled{\textbf{Parameter}}{\textbf{Options}}
\twocolitem{\textbf{X size}}{Number of columns in image file}
\twocolitem{\textbf{Y size}}{Number of rows in image file}
\twocolitem{\textbf{Samples per pixel}}{Numbers of samples taken
per pixel in both the x and y directions. For example, if the
\texttt{Samples per pixel} is set to \texttt{3}, then for every
-pixel in the image file 9 samples ($3\times3$) are averaged.}
+pixel in the image file 9 samples \latexonly{($3\times3$)}\latexignore{(3 x 3)}
+are averaged.}
\end{twocollist}
-\subsection{Projection Dialog}\index{Projection collection}
+\subsection{Projection Dialog}\label{IDH_DLG_PROJECTIONS}\index{Dialog!Projections}
This creates a projection file from a phantom. The options
available when collecting projections are:
geometries, this should be at least \texttt{2.0} to avoid artifacts.}
\end{twocollist}
-\subsection{Advanced Options}
+\textbf{Advanced Options}
+
\begin{twocollist}
\twocolitem{\textbf{Rotation Angle}}{Sets the rotation amount as a
-multiple of pi. For parallel geometries use a rotation angle of \texttt{1}
+multiple of \latexonly{$\pi$.}\latexignore{pi.} For parallel geometries use a rotation angle of \texttt{1}
and for equilinear and equiangular geometries use a rotation angle
of \texttt{2}. Using any other rotation angle will lead to artifacts.}
\end{twocollist}
\item History labels (text descriptions of the processing for this image)
\end{itemize}
-\subsection{File - Export}\index{Image export}
+\subsection{File - Export}\label{IDH_DLG_EXPORT}\index{Image!Export}
This command allows for exporting image files to a standard
graphics file format. This is helpful when you want to take an
image and import it into another application. The current
\helprefn{intensity scale}{intensityscale} is used when exporting
-the file. The support file formats are:
+the file. The supported graphic formats are:
\begin{twocollist}
\twocolitem{\textbf{PNG}}{Portable Network Graphics format. This uses 8-bits or
\end{twocollist}
-\subsection{View}\label{intensityscale}
+\subsection{View}\label{intensityscale}\index{Intensity Scale}
These commands are used change the intensity scale for viewing the image.
These commands do not change the image data. When the minimum intensity is
set, then the color pure black is assigned to that image intensity. Similarly,
when the maximum intensity is set, the the color pure white is assigned to that
image value.
-\subsubsection{Set}
-This command displays up a dialog box that allows you to set the lower
+Changing the intensity scale is useful when examining different image features.
+In clinical medicine, the intensity scale is often changed to examine bone
+(high intensity) verses soft-tissue (medium intensity) features.
+
+\subsubsection{Set}\label{IDH_DLG_MINMAX}
+This command displays a dialog box that allows you to set the lower
and upper intensities to display.
-\subsubsection{Auto}
-This command displays up a dialog box that allows \ctsim\ to automatically
-make an intensity scale. The options that \ctsim\ needs to make this
+\subsubsection{Auto}\label{IDH_DLG_AUTOSCALE}
+This command displays a dialog box that allows \ctsim\ to automatically
+make an intensity scale. The parameters that \ctsim\ needs to make this
automatic scale are:
\begin{twocollist}
As an example, if \texttt{median} is selected as the center and
\texttt{0.5} is selected as the width, the the minimum intensity will
-be $median - 0.5 \times standard deviation$ and the maximum will be
-$median + 0.5 \times standard deviation$.
+be \latexonly{$median - 0.5 \times standardDeviation$}\latexignore{\emph{median - 0.5 x standardDeviation}}
+and the maximum will be \latexonly{$median + 0.5 \times standardDeviation$.}\latexignore{\emph{
+median + 0.5 x standardDeviation}.}
\subsubsection{Full}
This command resets the intensity scale to the full scale of the image.
\subsubsection{Add, Subtract, Multiply, Divide}
These are simple arithmetic operations. \ctsim\ will display a dialog
box showing all of the currently opened image files that are the
-same size of the active image. After the selection of a compatible image,
+same size as the active image. After the selection of a compatible image,
\ctsim\ will perform the arithmetic operation on the two images and
make a new result image.
\subsubsection{Image Size}
-This command will generate a new window with the current image scaled to
-any size. Currently, \texttt{bilinear} interpolation provides the best
-image quality.
+This command will generate a new image based on the current image. The new
+image can be scaled to any size. A dialog
+appears asking for the size of the new image. Bilinear interpolation
+is used when calculating the new image.
\subsubsection{3-D Conversion}
Generates a 3-dimensional view of the current phantom. This view can be
are presented on the \texttt{View} menu and include:
\begin{itemize}
-\item Surface plot versus wireframe
-\item Smooth shading versus flat shading
-\item Lighting on or off
-\item Color scale on or off
+\item Surface plot versus wireframe plot.
+\item Smooth shading versus flat shading.
+\item Lighting on or off.
+\item Color scale on or off.
\end{itemize}
\subsection{Filter}\index{Image filter}
-These commands filter and modify the image.
+These commands filter and modify the image
\subsubsection{Arithmetic}
-These are simple arithmetic functions that should be self-explanatory.
+These commands operate on the image on a pixel-by-pixel basis. The commands
+support both real and complex-valued images. The available arithmetic commards are:
+
+\begin{twocollist}
+ \twocolitem{\textbf{Invert}}{Negate pixel values.}
+ \twocolitem{\textbf{Log}}{Take natural logrithm of pixel values.}
+ \twocolitem{\textbf{Exp}}{Take natural exponent of pixel values.}
+ \twocolitem{\textbf{Square}}{Take square of pixel values.}
+ \twocolitem{\textbf{Square root}}{Take square root of pixel values.}
+\end{twocollist}
+
\subsubsection{Frequency Based}
This commands allow the Fourier and inverse Fourier transformations of
images. By default, the transformations will automatically convert
-images from Fourier to natural order as expected. For example, \texttt{2-D FFT}
+images between Fourier to natural orders as expected. For example, \texttt{2-D FFT}
will transform the points into natural order after the Fourier transform.
Similarly the inverse, \texttt{2-D IFFT}, will reorder the points from
natural order to Fourier order before applying the inverse Fourier transformation.
The commands plot rows and columns of images. There are also commands
that perform FFT and IFFT transformations prior to plotting.
-\subsubsection{Image Comparison}
+\subsubsection{Image Comparison}\label{IDH_DLG_COMPARISON}\index{Image!Comparison}
This command performs statistical comparisons between two images. An option
also exists for generating a difference image from the two input images.
\item The variables used when generating the projections from the phantom
\end{itemize}
-\subsection{Process - Convert Polar Dialog}\label{convertpolardialog}\index{Polar conversion}
+\subsection{Process - Convert Polar Dialog}\label{IDH_DLG_POLAR}\index{Polar conversion}
Creates an image file with the polar conversion of the projection data. The options to set are:
\begin{twocollist}
projections are Fourier transformed prior to conversion to polar
image.
-\subsection{Reconstruct - Filtered Backprojection Dialog}\index{Reconstruction dialog}
+\subsection{Reconstruct - Filtered Backprojection Dialog}\label{IDH_DLG_RECONSTRUCTION}\index{Dialog!Reconstruction}
This dialog sets the parameters for reconstructing an image from projections
using the Filtered Backprojection technique.
}
\end{twocollist}
-\subsection{Advanced Options}
+\textbf{Advanced Options}
These options are only visible if \emph{Advanced Options} has been
selected in the \texttt{File - Preferences} dialog. These parameters
projects / ctsim.git / commitdiff