- fitrans [transformation and options] <input> [-o|--output <output>]
- The main purpose of this program is to perform specific or generic geometric transformations on the input image.
- -h, --help
- Gives general summary about the command line options.
- Gives a detailed list of command line options.
- 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.
- Simple linear interpolation between pixels, with no exact flux conservation (just a multiplication by the Jacobian of the transformation).
- Linear interpolation between the pixels involving exact flux conservation by integrating on the image surface.
- Bicubic spline interpolation between pixels, with no exact flux conservation (just a multiplication by the Jacobian of the transformation).
- 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 of the transformation. In the actual implementation, the only supported type for a transformation is polynomial.
- Polynomial order for the transformation.
- 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.
- 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.
- 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:
- Do a spline interpolation smoothing
- Do a polynomial interpolation smoothing
- Spatial order of the smoothing function. The order in the X and Y coordinates can be set independently, by setting xorder=... or yorder=....
- Scale the resulting smoothed image to have a mean of 1.
- The resulting image will be the original image divided by the best fit smoothed surface.
- Do a box filtering with the given halfsize.
- Use the mean value of the pixels for the box filtering.
- Use the median value of the pixels for the box filtering.
- 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.
- -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.