AIPS HELP file for BLANK in 31DEC22
As of Wed Nov 29 11:14:06 2023
BLANK: Blanks out non-signal portions of images
INNAME Input image name (name)
INCLASS Input image name (class)
INSEQ 0.0 9999.0 Input image name (seq. #)
INDISK 0.0 9.0 Input image disk unit #
IN2NAME Cutoff image name (name)
IN2CLASS Cutoff image name (class)
IN2SEQ 0.0 9999.0 Cutoff image name (seq. #)
IN2DISK 0.0 9.0 Cutoff image disk unit #
OUTNAME Output image name (name)
OUTCLASS Output image name (class)
OUTSEQ -1.0 9999.0 Output image name (seq. #)
OUTDISK 0.0 9.0 Output image disk unit #.
BLC Bottom left corner of input
TRC Top right corner of input
BCHAN -1.0 512.0 First x point (after BLC) to
be left possibly unblanked
ECHAN -1.0 512.0 Last x point (after BLC) to
be left possibly unblanked
DOOUTPUT -1.0 1.0 Write avg. of blanks image
DOALIGN -2.0 1.0 > 0 => alignment of input and
clip images required
OPCODE How to do blanking: 'TVCU',
DPARM Parameters: (see HELP)
(1) window width, etc.
(2) center on peak, 1st mom.
(3) F1 flux cutoff
(4) F2 flux cutoff
(5) > 0 =>blank with DPARM(6)
<= 0=> use magic-values
(6) see DPARM(5)
DOINVERS -1.0 1.0 TVCU only: >0 => blank blotch
<= 0 => blank outside blotch
TVCHAN 1.0 16.0 TV channel to use (TVCU only)
PIXRANGE Min,Max of image intensity
Max <= Min => entire range
FUNCTYPE Image intensity transfer func
'LN' Linear. unknown=>'LN'
'SQ' Square root
'NE' Negative linear
'NG' Negative logarithmic
'NQ' Negative square root
TXINC 0.0 32.0 TVCU only: load every TXINCth
pixel on x axis
TYINC 0.0 32.0 TVCU only: load every TYINCth
pixel on y axis
Task: Attempts to determine which regions of an image have real signal
and then blanks the rest. This operation is useful to prepare
images suitable for summing, moment computations, and the like.
The output should not be used for Gaussian fitting since it lacks
suitable baseline regions. BLANK is also useful to eliminate bad
regions from non-synthesis images (e.g. optical ones). (Normally
BLANK will be used on images with frequency or velocity as the
first axis, but it will procede with others as well. Even for
spectral-line problems, the first axis need not be frequency or
velocity for correct functioning with OPCODEs 'TVCU', 'SELC', and
'IN2C'.) Optionally, the task will write an n-1 dimensional
image consisting of the average of those pixels blanked along
each row. (Zero is used as the average if there are no blanked
pixels in a row.)
INNAME.....Input image name (name). Standard defaults.
INCLASS....Input image name (class). Standard defaults.
INSEQ......Input image name (seq. #). 0 => highest.
INDISK.....Disk drive # of input image. 0 => any.
IN2NAME....Clip level image name (name) (IN2C only).
IN2CLASS...Clip level image name (class) (IN2C only).
IN2SEQ.....Clip level image name (seq. #) (IN2C only).
0 => highest.
IN2DISK....Disk drive # of clip level image (IN2C only).
0 => any.
OUTNAME....Output image name (name). Standard defaults.
OUTCLASS...Output image name (class). Standard defaults.
Used only for the blanked image. If a row-by-row
average of the blanked pixels is written, a class
of AVGBLK will be used.
OUTSEQ.....Output image name (seq. #). Standard defaults.
OUTDISK....Disk drive # of output image. 0 => highest number
with sufficient space.
BLC........Bottom right corner in input image of desired
subimage. Default is entire image.
TRC........Top right corner in input image of desired
subimage. Default is entire image.
BCHAN......First x pixel (after application of BLC(1)) which
is allowed to be left unblanked in the output
image. This option is useful only if the average
of the blanked pixels is written and provides a
wider region over which the averaging is performed.
The actual number of points on the output image row
is given by ECHAN - BCHAN + 1. (0 => 1).
ECHAN......The last x pixel (after application of BLC(1))
which is allowed to be left unblanked in the output
image. 0 => TRC(1) - BLC(1) + 1.
DOOUTPUT...True (> 0) requests that the n-1 dimensional image
consisting of the average of the blanked pixels be
DOALIGN....Controls how the input and clip images are aligned
(see HELP DOALIGN). True (>.1) means that the
images must agree in their coordinates. Note that
a 2-dim image (e.g. RA-Dec) may be used to clip a
3-dim image in several of the possible
transpositions (e.g., RA-Dec-V, V-RA-Dec, RA-V-Dec,
but not V-Dec-Ra for example) when the headers
match. DOALIGN = -2 means ignore the headers and
align at (1,1,...).
OPCODE.....How the program is to do blanking:
'TVCU' : display image planes (any transposition)
on TV and mark signal regions with cursor
'FIXW' : fixed window BCHAN through ECHAN
'FLTW' : floating window of fixed width
'MOMW' : window with width set by 2nd moment
'FLUW' : window set by fluxes (from peak through
last pixel > F1 on each side plus "slop")
'SELC' : If F1 < F2, keep all F <= F1 and F >= F2.
If F1 > F2, keep all F1 >= F >= F2. Thus,
if F1 < F2, keep all F outside the F1->F2
range and, if F1 > F2, keep all F inside
the F2->F1 range.
'IN2C' : Like 'SELC', except the test is done on a
second image (IN2NAME et al.) rather than
the input image.
'RADI' : Flag all pixels outside specified radius
(1) 'FLTW' window size in x pixels.
'MOMW' window size = DPARM(1) * 2nd moment
'SELC','IN2C','FLUW' "slop" - extend "good"
areas by DPARM(1) pixels in each direction
'RADI' - radius in arc sec outside of which all
pixels are flagged.
(2) 'FLTW','MOMW','FLUW' center window on first
moment (<= 0) or on peak intensity (> 0).
(3) (Called F1 above for 'SELC','IN2C','FLUW'.)
Also ignore in moment computations all
intensities < F1. Units are those of image.
(4) (Called F2 above for 'SELC','IN2C'.) Units are
those of image.
(5) <= 0. -> retain existing magic-value blanks and
use magic-values for newly blanked pixels.
> 0. -> change all magic values to DPARM(6)
(6) if DPARM(5) > 0, replace all blank values by
DOINVERS...For TVCU only: if true (> 0.), blank the pixels
inside the blotch regions; if false (<= 0.), blank
the pixels outside the blotch regions.
TVCHAN.....TV channel to use (<= 0 -> 1).
PIXRANGE...Min,Max of image intensity for scaling to the TV.
Used for 'TVCU' only. 0 => full range of image.
FUNCTYPE...Image intensity transfer function (TVCU only)
'LN' => linear; 'LG' => log; 'NE' => negative lin.
'NG' => negative log; 'SQ' => square root,;
'NQ' => negative square root; others => linear.
TXINC......Load only every TXINC'th x-pixel to the TV. 0 -> 1.
(It is used to avoid many separate loads of sub-
images when the input image is large.)
TYINC......Load only every TYINC'th y-pixel to the TV. 0 -> 1.