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ccdfill - patch up the holes in an image
ccdfill [parameter=value]
ccdfill patches up the holes in an image.
Currently a simple
2-dimensional planar fit is done to the pixel values surrounding ’bad’ pixels.
The size of this area can be choosen by the user.
This procedure will obviously
not conserve flux (see also all=t below), and has to be used with caution.
The following parameters are recognized in order; they may
be given in any order if the keyword is also given. Use --help to confirm
this man page is up to date.
- in=in_ccd
- Input image(3NEMO)
file. No default.
- out=out_ccd
- Output image file. No default.
- n=
- Number of neighbor cells at
one side to use in interpolation/fit. The total number of cells used in
the fit will hence be at most 4*n*(n+1) (this already excludes the central
pixel, n=1 uses 8 cells, n=2 uses 24 etc.) [Default: 1].
- bad=zvalue
- Value
in the map that should be patched. [Default: 0.0].
- all=t|f
- Normally only bad
pixels are patches. By setting all=t all pixels are re-fitted with a planar
fit, effectively smoothing the map. This will obviously not conserve flux,
where applicaple, and should be used with caution. Default: f
- m=
- Minimum
number of neighbors needed to allow a fit. Normally 3 is enough, though
this tends to add to edges. 4 would be more conservative, in which case
iter>1 can be used. Default: 4
- iter=
- Minimum number of iterations. 0 is also
an allowed value, in which case the image will just be copied unmodified.
Default: 1
- xmirror=t|f
- Use points mirrored in X to get near a border. [Default:
f]
- ymirror=t|f
- Use points mirrored in Y to get near a border. [Default: f]
- spike=
- If given, for each point in the map, if a point deviates more than
spike from all it’s 4 non-bad direct neighbors, this value will be reset
to bad before the actually filling will take place. Default: none (not applied)
With m=3 you will see some singular matrix warnings, and patched
values will be bogus. It is better to set m=4 for those cases.
Edge effects
will occur for large values of iter, use with caution. Really a better
bi-linear interpolation is needed. See also ccdintpol(1NEMO)
if your irregulaties
are regular enough.
image(3NEMO)
, ccdmath(1NEMO)
, ccdsmooth(1NEMO)
,
ccdintpol(1NEMO)
Peter Teuben
10-Dec-93 V1.0 Created PJT
22-feb-97 V1.1 added bad= PJT
19-feb-02 V1.2 added all=, m= PJT
3-may-03 V1.3 added iter= PJT
3-may-2017 V2.0 added spike= PJT
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