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Man page of X-GEN
X-GEN
Section: X-GEN Commands (1)
Updated: April 2005
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NAME
X-GEN - border
SYNOPSIS
border
[-v] [-ds] [startfm] [endfm] [cutoff]
DESCRIPTION
"border" computes the active area of the detector face.
The active area is determined in the following way:
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1. A group of images f=1,...N is read in and the mean intensity at
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each pixel <C(X,Y)> is calculated over those images:
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<C(X,Y)> = [SUM(f) C(X,Y,f) ] / N
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2. The mean of all those values is calculated for all X=1,...W
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and Y = 1 ... H:
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M = SUM(X,Y) <C(X,Y)> / (W*H)
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3. Any pixel for which <C(X,Y)> < Q * M is considered outside the
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active area. Any pixel for which <C(X,Y)>= Q*M is considered
inside the active area. Q is typically 0.42 but is
user-selectable. 4. The outside few pixels are excluded.
The functionality of border (including the run-time options) has
now been bound up inside "spots", so there should be no reason to
run this program on a stand-alone basis.
OPTIONS
- -v
-
This toggles whether additional diagnostics are written
to the XLOG log file during the `border' operation.
- -d<val>
-
This value defines the fraction of the dark-current that
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will be subtracted from each detector image in determining the
background values used in the border calculation. Default value: 0.
- -s<val>
-
This defines how many pixels "in" from the edge of the
-
computed active area the defined border will be drawn. Thus if the
computed X extremes of the active area at a particular Y value are
X = 3 to 502, and the value given in this parameter is 7, then the
defined X border at that Y value will be (3+7, 502-7), or (10,
495). Default value: 0.
- startfm
-
This specifies the first frame in the range to be
-
examined in determining which pixels are to be active on the
detector face. Default value: first frame enumerated in frame index.
- endfm
-
This specifies the last frame in the range to be examined
-
in determining which pixels are to be active on the detector face.
Default value: startfm + delta, where delta is a detector-type-
specific value: 20-30 for SDMS, Xentronics, and FAST
detectors;; 5-8 for all image plate and CCD detectors. If there
are fewer than delta images in the FRAMES file, then endfm will be
the last frame enumerated there.
- cutoff
-
This specifies the fraction of the mean background count
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that will be treated as inactive. Thus if the average background
count is 200 pixels and the fraction specified here is 0.4, then
pixels with counts less than 0.4 * 200 = 80 will be treated as
inactive. Default value: detector-type-dependent, ranging between
0.36 and 0.42.
EXAMPLES
- border
-
Determine the active area on the default number of images,
with the default cutoff for the fraction treated as inactive:
-
border -q0.41 12 30 Determine the active area over images 12 through 30,
-
using an inactive-fraction cutoff value of 0.41
-
To find the active area over images 12 through 30,
using a cutoff of 0.41:
REPORTING BUGS
Report bugs to Andy Howard at howard@iit.edu or 312-567-5881.
COPYRIGHT
Copyright © 2002, Illinois Institute of Technology.
See the file 'LICENSE' for information on usage and redistribution
of this file, and for a DISCLAIMER OF ALL WARRANTIES
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- EXAMPLES
-
- REPORTING BUGS
-
- COPYRIGHT
-
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Time: 02:08:09 GMT, October 03, 2005