AIPS HELP file for SABOX in 31DEC20
As of Tue Jul 7 4:33:31 2020
SABOX: Find Clean boxes in a set of images
INNAME Image name (name)
INCLASS Image name (class)
INSEQ 0.0 9999.0 Image name (seq. #)
INDISK 0.0 9.0 Image disk drive #
NFIELD 1.0 4096.0 Number of facets per width
NGAUSS 0.0 10.0 Number Gaussian widths
BLC 0.0 Bottom left corner each facet
TRC 0.0 Top right corner each facet
BOXFILE Input box file name
OBOXFILE Output box file name
APARM (1) N sigma cutoff 0->3
(2) edge skip in pixels 0->5
(3) extend box size in pixels
(4) box type: 0 choose
(5) > 0 don't use ACTNOISE
(6) > 0 forbid diagonal
(7) Min island size, 0 -> 2
(8) > 0 don't delete overlaps
BADDISK 0. 36. Disks to avoid for scratch
Use: SABOX resembles SAD except that it does not fit the sources it
finds. Instead, it determines a Clean box to surround the source
and writes it to an output "box file" for later input to IMAGR or
other tasks which process box files.
The input box file is copied to the output box file, omiting any
Clean boxes. Then the task loops over facets finding first the
rms of the facet, second all source islands exceeding N*rms, and
finally writing out boxes fit to those islands. All boxes and
the rms are found only for pixels within an inscribed ellipse in
the facet. Note that finding the rms is moderately expensive
except when the ACTNOISE keyword has been written into the
header by IMEAN.
INNAME......The input image name. Standard defaults.
INCLASS.....The input image class. The first 2-3 characters determine
a base name and the last 4-3 are a numeric field number
nnn (i.e. ICL001 or IIM012 or IC3245). Class names for
higher fields are nnn through nnn+NFIELD-1. Old style
names in which the last 2 characters represent the field
number minus one in extended Hex are also supported.
INSEQ.......The input image sequence number. 0 => high
INDISK......The input image disk drive no. 0 => any
NFIELD......The number of fields per Gaussian width. The total
number of facets will be NFIELD * NGAUSS <= 4096.
NGAUSS......Number of Gaussian widths in the facets.
BLC.........The bottom left-hand pixel of the input image(s) which
becomes the bottom left corner of the subimage
processed. The value 0 means 1. The output boxes will
be in true image X,Y pixels. Use this to select planes
in a cube - but note that the plane number is not
recorded in the box file.
TRC.........The top right-hand pixel of the input image which
becomes the top right corner of the subimage processed.
The value 0 means to use the full axis dimension on that
BOXFILE.....Input box file - defines field centers and the like (see
HELP IMAGR). Any Clean boxes are discarded.
OBOXFILE....Text file containing all non-box information from
BOXFILE plus all boxes found by SABOX.
(1) Find islands down to APARM(1) * rms of facet.
0 => 3.
(2) Inscribed ellipse radius is APARM(2) pixels less
than the image half width/height. 0 -> 5
If APARM(2) < 0, use abs(APARM(2)) as an edge skip
but consider all image pixels in the rectangular
area blc+edgskp to trc-edgskp. Otherwise, pixels
outside an inscribed ellipse are discarded.
(3) Extend box out from island by APARM(3) pixels.
No default (< 0 => 1).
(4) -1 => use rectangular boxes always
+1 => use circular boxes always
0 => choose (circles if x,y sizes of island are
nearly the same, otherwise rectangles)
(5) > 0 => find rms the hard way even if ACTNOISE
present. The "hard" way works well since each
image is held in memory. If you want the same RMS
to be used for each facet, then ACTNOISE should be
set to that RMS in each facet header and APARM(5)
set to 0.
(6) > 0 => do not allow islands to join along diagonals
(not usually needed and can make odd shaped boxes)
(7) Minimum linear size of islands in either axis.
Islands that are smaller are kept, but only if the
center pixel is > 3 * APARM(1) * rms.
(8) After all the boxes are found, SABOX will compare
the boxes in each facet to those in the other
facets of the same resolution. If overlaps are
found, the smaller of the 2 overlapped boxes will be
deleted. If APARM(8) > 0, this test is not done.
BADDISK.....Disks to avoid for the scratch files.