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.TH RADON 1 "Ultrasonics Laboratory"
.SH NAME
radon - Generate a Radon Space Image of Scan Data
.SH SYNOPSIS
radon [options...]
.SH DESCRIPTION
.B Radon
reads radon space data as generated by 
.B gen(1)
and calculates
a 128 x 128 histogram 
representing the polar coordinates of
each ray in the scan.
.PP
The input file for 
.B radon
should consist of two arrays of 
single precision floating point numbers
for each flash in the scan.
The first array represents the distance (l)
of the scan line from the origin,
while the second array represents its
direction (theta).
The default file is named
.B radon.
.PP
The final radon space image is calculated by 
counting the number of points that are sampled
at each of the 128 x 128 squares.
The image is then scaled so that the maximum
number will be shown as white
on a black background.
.PP
There are many options to control the amount
of data used to generate the plot.
These parameters can be set from the command
line by listing the name of the variable,
an equals sign and
then the desired value.
The desired value should be either a number
or a file depending on the type of variable.
The parameters that can be set (and their
default values in parenthesis) are:
.TP 13
.B nfl=100
is the number of flashes per traverse in fifth 
generation scanners.
For first generation scanners this would represent the
number of rays per projection.
For third generation scanners this parameter should be
set to 1.
.TP
.B n=20
is the number of detectors.
For first generation scanners this is 1.
For second generation data it is the number of rays.
.TP
.B k=11
is the number of traverses during the scan.
Each traverse gives information over 
nfl x n rays.
.TP
.B radius=1
is the radius of the scan circle.
All values in the final image
outside of this radius are set to zero.
This cleans up the rough edges on the picture.
Setting this parameter also sets the
.B -x
flag.
.TP
.B sd=all
calculates the radon space data for a single detector
in the array.
If this parameter is not used then
the data for all detectors is used.
.TP
.B if=radon
is the radon space input file.
This will normally be generated
by 
.B gen
(1)
but could also represent points
in any type of polar problem.
.TP
.B of=pic
is the output file name.
The result will be a
128 x 128 array of eight bit data
that can be displayed on 
either the Comtal
or the Grinnel.
See
.B display(1)
or 
.B dgrin(1).
.PP
There are also several flags
that can be set from the command line.
They are:
.TP 13
.B
-z(off)
zero's all pixels outside a radius specified by the
.B radius=
flag. 
This is used to clean up a picture.
.TP
.B -s(off)
plot the results from only one detector.
The desired detector is set with the 
.B sd=
parameter.
Normally the results for all detectors is printed.
.TP
.B -q(off)
show the results only in the first quadrant
(theta between 0 and 90 degrees).
Normally the plot will show the entire plane.
.TP
.B -n(off)
only show the points in radon space for
detectors with negative distances.
Normally the points scanned in radon space 
are shown for all detectors.
.TP
.B -p(off)
do not print the program statistics.
Normally all the statistics are printed.
.SH FILES
.TP 13
radon
default input file.
.TP
pic 
default output file.
The output file will consist of an 128 x 12888 array of
eight bit bytes.
.SH SEE ALSO
.B gen
(1).
.SH DIAGNOSTICS
An error message is printed if either of the two files
can not be opened for input or if the input
arguments are incorrect.