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FITRANS(1) |
User Commands |
FITRANS(1) |
NAME¶
fitrans - performing spatial transformations on the input image
SYNOPSIS¶
fitrans [transformation and options] <input>
[-o|--output <output>]
DESCRIPTION¶
The main purpose of this program is to perform specific or generic geometric
transformations on the input image.
OPTIONS¶
General options:¶
- -h, --help
- Gives general summary about the command line options.
- --long-help, --help-long
- Gives a detailed list of command line options.
- --wiki-help, --help-wiki, --mediawiki-help,
--help-mediawiki
- Gives a detailed list of command line options in Mediawiki format.
- --version, --version-short, --short-version
- Gives some version information about the program.
- -i, --input <image file>
- Name of the input FITS image file.
- -o, --output <image file>
- Name of the output FITS image file.
- -b, --bitpix <bitpix>
- Standard FITS output bitpix value.
- -D, --data <spec>
- Output pixel data format specification.
- -T, --input-transformation <transformation file>
- Name of the file which contains the transformation description.Such a file
can be created e.g. by the programs `grtrans` or `grmatch`. This file
contains basically the same set of <keyword> = <value> pairs
as it is used after the -t|--transformation option (see
there).
- -t, --transformation <transformation>
- Comma-separated list of parameters for the spatial transformation, see
section "Parameters for spatial transformations" below.
- -e, --shift <dx>,<dy>
- Imply a transformation that shifts the image by
<dx>,<dy>.
- --reverse, --inverse
- Apply the inverse transformation to the image rather than the original
one.
- -m
- Simple linear interpolation between pixels, with no exact flux
conservation (just a multiplication by the Jacobian of the
transformation).
- -l
- Linear interpolation between the pixels involving exact flux conservation
by integrating on the image surface.
- -c
- Bicubic spline interpolation between pixels, with no exact flux
conservation (just a multiplication by the Jacobian of the
transformation).
- -k
- Interpolation by integrationg the flux on a biquadratic interpolation
surface, yielding exact flux conservation.
- -s, --size <sx>,<sy>
- The size of the output image if it should differ from the original image
size.
- -f, --offset <x>,<y>
- Zero-point coordinate of the output image in the input image.
- type=<type>
- Type of the transformation. In the actual implementation, the only
supported type for a transformation is "polynomial".
- order=<order>
- Polynomial order for the transformation.
- dxfit=<coefficients>
- Comma-separated list of the polynomial coefficients for the X coordinate.
The number of coefficients must be 1, 3, 6, ... for the orders 0, 1, 2,
... respectively.
- dyfit=<coefficients>
- Comma-separated list of the polynomial coefficients for the Y
coordinate.
- -z, --zoom <factor>
- Zoom the image by the given (integer) factor, involving a biquadratic
subpixel-level interpolation and therefore exact flux conservation.
- -r, --shrink <factor>
- Shrink the image by the given (integer) factor.
- -d, --median
- Use a median-based averaging during the shrinking operation.
- --optimistic-masking
- Imply some optimism during the shrinking operation: masked pixels are
ignored during the averaging process and the final mask will be computed
in a complement manner.
- -g, --magnify <factor>
- Same as zooming the image but there is no subpixel-level
interpolation.
Large-scale image smoothing:¶
- -a, --smooth <parameters>
- Perform a smoothing on the image. The parameters of the smoothing are the
following:
- spline
- Do a spline interpolation smoothing
- polynomial
- Do a polynomial interpolation smoothing
- [xy]order=<order>
- Spatial order of the smoothing function. The order in the X and Y
coordinates can be set independently, by setting "xorder=..." or
"yorder=...".
- unity
- Scale the resulting smoothed image to have a mean of 1.
- detrend
- The resulting image will be the original image divided by the best fit
smoothed surface.
- [xy]hsize=<halfsize>
- Do a box filtering with the given halfsize.
- mean
- Use the mean value of the pixels for the box filtering.
- median
- Use the median value of the pixels for the box filtering.
- iterations=<iterations>
- Number of iterations to reject outlier pixels from the box.
- lower, upper, sigma=<sigma>
- Lower, upper or symmetric rejection level in the units of standard
deviation.
Noise estimation:¶
- -n, --noise
- Derive an image which reflects the "noise level" of the
image.
Slicing or exploding data cube images:¶
- -y, --layer <layer>
- Layer (z-axis index) of the desired image slice.
- -x, --explode <basename>
- Explode the input image into individual planar (two dimensional) FITS
image. The basename must contain at least one printf-like tag of %d, %i,
%o, %x or %X that is replaced by the appropriate layer number index.
- -y, --first-layer <n>
- Use the specified value for the first layer index. The subsequent layer
indices are incremented normally. By default, the index of the first data
cube layer is 0.
COPYRIGHT¶
Copyright © 1996, 2002, 2004-2008, 2010-2015; Pal, Andras
<apal@szofi.net>