AIPS HELP file for BSCOR in 31DEC22
As of Tue Dec 6 16:09:29 2022
BSCOR: Combines beam-switched images
INNAME Input "plus" beam name
INCLASS Input "plus" beam class
INSEQ 0.0 9999.0 Input "plus" beam seq. #
INDISK 0.0 9.0 Input "plus" beam disk #
IN2NAME Cutoff "minus" beam name
IN2CLASS Cutoff "minus" beam class
IN2SEQ 0.0 9999.0 Cutoff "minus" beam seq. #
IN2DISK 0.0 9.0 Cutoff "minus" beam disk #
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
FACTOR Correct the beam throws by
multiplying by FACTOR
ORDER Baseline order (0 or 1)
DPARM Parameters: (see HELP)
(1) scale factor plus image
over minus (0 -> 1)
(2) > 0 => apply scale before
differencing, else apply
scale with convolution
(3-4) x-pixel baseline region
1 for both images
(5-6) x-pixel baseline region
2 for both images
DOALIGN How closely coordinates agree
Task: Combines the two images of beam-switched data. A constant
baseline is fit to two windows in each row and subtracted
from that row. Then (optionally) the plus image is scaled
with respect to the minus image. The two are then differenced
and convolved with a one-dimensional function on a row by row
basis to combine the two images.
INNAME.....Input plus beam image name. Standard defaults.
INCLASS....Input plus beam image class. Standard defaults.
INSEQ......Input plus beam image seq. #. 0 => highest.
INDISK.....Disk drive # of plus beam image. 0 => any.
IN2NAME....Input minus beam image name. ' ' => INNAME
IN2CLASS...Input minus beam image class. ' ' => INCLASS
(with + -> -)
IN2SEQ.....Input minus beam image seq. #. 0 => INSEQ
IN2DISK....Disk drive # of minus beam image. 0 => INDISK
OUTNAME....Output image name (name). Standard defaults.
OUTCLASS...Output image name (class). Standard defaults.
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.
FACTOR.....Change the beam throws by FACTOR.
ORDER......Order of baseline removed from each row of each image.
Only 0 and 1 are allowed.
(1) The plus beam may be scaled by DPARM(1) wrt the minus
beam. (You may need to use IMFIT to determine this
ratio. Be sure to fit a baseline as well as a
Gaussian.) 0 => 1.
(2) The ratio may be applied at two different stages:
if DPARM(2) > 0, the images are scaled before they are
differenced. Otherwise, the scaling is done through a
modification of the convolution function.
(3) Start x pixel of both images to use for the first of
2 baseline regions. 0 => 1. N.B. this applies after
BLC(1) has been applied.
(4) End x pixel of both images to use for first baseline
region. 0 => all (not a good default).
N.B. above N.B.
(5) Start x pixel of both images to use for the second of
2 baseline regions. 0 => none. N.B. above N.B.
(6) End x pixel of both images to use for second baseline
region. 0 => all (an okay default).
It has been found by experimentation that it is essential
to use the same baseline regions for both images.
DOALIGN....The alignement of the two images is checked at a level
determined by DOALIGN.
= 1 => they must agree
= 0 => axis 1 must agree, 2 need only be close
= -1 => types and dimensions must agree
= -2 => only dimensions are checked