Construct a primary beam corrected image from an image and a primary beam pattern.
PARAMETER SUMMARY
imagename Name of the input (CASA, FITS, MIRIAD) image
pbimage Name of the image (CASA, FITS, MIRIAD) of the primary beam pattern or an array of pixel values.
outfile Name of output CASA image. If not specified, no image is written
but an image analysis tool which references the output image is returned.
overwrite If output file is specified, controls if an already existing file by the
same name can be overwritten. If true, the user is not prompted, the file
if it exists is automatically overwritten.
box Direction plane box specification, "blcx, blcy, trcx, trcy". Only one box
may be specified. If not specified, region is used if specified. If region
is also not specified, entire directional plane unioned with any chans and
stokes specification determines the region.
region Optional region file to use.
chans Optional contiguous frequency channel number specification. Not used if
region is specified. Default is all channels.
stokes Contiguous stokes planes specification. Not used if region is specified.
Default is all stokes.
mask Mask to use. See help par.mask. Default is none.
stretch Stretch the input mask if necessary and possible. See help par.mask.
mode Divide or multiply the image by the primary beam image. Minimal match supported. Default "divide"
cutoff PB cutoff. If mode is "d", all values less than this will be masked. If "m", all values greater will be masked. Less than 0, no cutoff. Default no cutoff
wantreturn If true, return an image analysis tool referencing the collapsed image, if
false, return false.
DESCRIPTION
Correct an image for primary beam attenuation using an image of the primary beam pattern.
The primary beam pattern can be provided as an image, in which case 1. it must have the same
shape as the input image and its coordinate system must be the same, or 2. it must
be a 2-D image in which case its coordinate system must consist of a (2-D) direction
coordinate which is the same as the direction coordinate in the input image and
its direction plane must be the same shape as that of the input image. Alternatively,
pbimage can be an array of pixel values in which case the same dimensionality and
shape constraints apply.
An image tool referencing the corrected image is returned if wantreturn=True. The corrected image will also
be written to disk if outfile is not empty (and overwrite=True if outfile already exists).
One can choose between dividing the image by the primary beam pattern (mode="divide") or
multiplying the image by the primary beam pattern (mode="multiply"). One can also choose
to specify a cutoff limit for the primary beam pattern. For mode="divide", for all pixels
below this cutoff in the primary beam pattern, the output image will be masked. In the
case of mode="multiply", all pixels in the output will be masked corresponding to pixels
with values greater than the cutoff in the primary beam pattern. A negative value for
cutoff means that no cutoff will be applied, which is the default.
EXAMPLE
impbcor(imagename="attunuated.im", pbimage="mypb.im", outname="pbcorred.im", mode="divide", cutoff=0.1)
1.8.0