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median_filter
This program produces the median filtered map of an input HEALPix map
(polarised or unpolarised). The
neighborhood on the which the median is computed is defined as a disk of
user-defined radius
Location in HEALPix directory tree:
src/f90/median_filter/median_filter.f90
FORMAT %
median_filter [options] [parameter_file]
COMMAND LINE OPTIONS
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-d
-
--double
- double precision mode (see Notes on double/single precision modes on page
![[*]](crossref.png) )
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-s
-
--single
- single precision mode (default)
QUALIFIERS
-
simul_type =
- Either 1 or 2. If set to 1, only the temperature component of the
input map will be filtered. If set to 2, all the Stokes components available
in the input file will be filtered (default = 1)
-
infile =
- Name of the FITS file containing the map to be filtered
(default = '', no default input file).
-
mf_radius_arcmin =
- Radius in arcmin of the disk over which the
median is computed (default =
 where
is the input map pixel size).
-
fill_holes =
- If set to true, flagged pixels take for value the median of
the valid pixels surrounding them (if any). Otherwise they are left
unchanged.
(default = .false.). Note that y, yes,t, true, .true. and 1 are
interpreted as true, while n, no, f, false, .false. and 0 stand
for false.
-
mffile =
- Name of the FITS file containing the median filtered map
DESCRIPTION
Median_Filter produces a median filtered map in which the value of each pixel
is the median of the input map valid pixels found within a disk of given
radius centered on that pixel. A pixel flagged as 'non-valid' in the input map
can either be left unchanged or 'filled in' with the same scheme, if at
least one valid pixel is found among its neighbors.
If the map is polarized, each of the three Stokes components is filtered separately.
SUPPORT This section lists those routines and facilities (including those external to the Healpix distribution) which can assist in the utilisation of median_filter.
-
anafast
- This HEALPix Fortran facility can
analyse a HEALPix map.
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synfast
- This HEALPix facility can generate a
HEALPix map from a power spectrum Cl.
EXAMPLE # 1:
Median_Filter runs in interactive mode, self-explanatory.
EXAMPLE # 2:
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median_filter [option] filename |
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When 'filename' is present, median_filter enters the non-interactive mode and parses
its inputs from the file 'filename'. This has the following
structure: the first entry is a qualifier which announces to the parser
which input immediately follows. If this input is omitted in the
input file, the parser assumes the default value.
If the equality sign is omitted, then the parser ignores the entry.
In this way comments may also be included in the file.
In this example, the file contains the following qualifiers:
simul_type = 1
infile = map.fits
mf_radius_arcmin = 20.0
mffile = med.fits
Median_Filter reads the sky map from 'map.fits'. Since
fill_holes
has its default value, ..., The median will be computed on a disk of 20 arcmin
in radius, and the result will be written in 'med.fits'.
RELEASE NOTES
Initial release (HEALPix 2.00)
MESSAGESThis section describes error messages generated by median_filter
| Message |
Severity |
Text |
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can not allocate memory for array xxx |
Fatal |
You do not have
sufficient system resources to run this
facility at the map resolution you required.
Try a lower map resolution. |
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this is not a binary table |
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the fitsfile you have specified is not
of the proper format |
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there are undefined values in the table! |
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the fitsfile you have specified is not
of the proper format |
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the header in xxx is too long |
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the fitsfile you have specified is not
of the proper format |
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XXX-keyword not found |
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the fitsfile you have specified is not
of the proper format |
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found xxx in the file, expected:yyyy |
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the specified fitsfile does not
contain the proper amount of data. |
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Eric Hivon
2010-06-18
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