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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
Gives a detailed list of command line options.
−−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.
Spatial transformations:
−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.
−−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.
Parameters for spatial transformations:
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.
Other simple spatial geometric transformations:
−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.