mBackground - Online in the Cloud

PROGRAM:

NAME

mBackground - Remove a background plane from a FITS image

SYNOPSIS

mBackground [-d level] [-n(o-areas)] [-s statusfile] in.fits out.fits A B C

mBackground [-t] [-d level] [-n(o-areas)] [-s statusfile] in.fits out.fits images.tbl
corrfile.tbl

DESCRIPTION

Remove a background plane from a FITS image. The background correction applied to the
image is specified as Ax+By+C, where (x,y) is the pixel coordinate using the image center
as the origin, and (A,B,C) are the background plane parameters specified as linear
coefficients.

OPTIONS

-d level
Turns on debugging to the specified level.

-n Indicates that no area images are present (assumes equal weighting for each data
pixel)

-s statusfile
mBackground output and errors will be written to statusfile instead of stdout.

-t Run in table mode. Starts a group of mBackground runs in parallel, reading off the
same pair of tables to determine which files and background corrections to work
with. Recommended for running only on grids or parallel processors.

ARGUMENTS

in.fits
Input FITS file

out.fits
Output FITS file

A B C Corrections (as given by mFitplane or mFitExec)

images.tbl
When run as part of a GRID processing job, mBackground requires the image metadata
table to retrieve the filenames of images.

corrections.tbl
When run as part of a GRID processing job, mBackground requires a table of
corrections (from mFitplane and mFitExec) to apply to the corresponding image (from
images.tbl).

RESULT

Output FITS image with background subtraction applied.

MESSAGES

OK [struct stat = "OK"]

ERROR No status file name given

ERROR Cannot open status file: statusfile

ERROR No debug level given

ERROR Debug level string is invalid: string

ERROR Debug level value cannot be negative

ERROR Invalid input file filename

ERROR Invalid output file filename

ERROR A coefficient string is not a number

ERROR B coefficient string is not a number

ERROR C coefficient string is not a number

ERROR Invalid image metadata file: images.tbl

ERROR Image table needs columns cntr and fname

ERROR Hit end of image table without finding file name

ERROR Need columns: id,a,b,c in corrections file

ERROR Hit end of corrections table without finding data

ERROR FITS library error message

ERROR general error message

EXAMPLES

The following is sample output from mFitplane for a FITS image, in.fits: [struct
stat="OK", a=-0.000144415, b=-0.000133642, c=-31.8984, crpix1=758.5, crpix2=-1032,
xmin=-758.5, xmax=-349.5, ymin=1032, ymax=1498, xcenter=-555.007, ycenter=1265.26,
rms=0.576727]

We use the plane coefficients calculated by mFitplane to subtract the background from the
image:

$ mBackground projdir/in.fits bg_removed/in.fits -0.000144415 -0.000133642 -31.8984
[struct stat="OK"]

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