table of contents
| ASTSCRIPT-COLOR-FAINT-GRAY(1) | User Commands | ASTSCRIPT-COLOR-FAINT-GRAY(1) |
NAME¶
astscript-color-faint-gray - RGB image from FITS images showing bright and faint features
SYNOPSIS¶
astscript-color-faint-gray [OPTION] R.fits G.fits B.fits K.fits
DESCRIPTION¶
This script is part of GNU Astronomy Utilities 0.24.
This script generates a color image from three different images (RGB). In order to show the entire range of pixel values, an asinh transformation is used. For more on the definiton of this algorithm see Lupton et al. 2004:
For more information, please run any of the following commands. In particular the first contains a very comprehensive explanation of this script's invocation: expected input(s), output(s), and a full description of all the options.
- Inputs/Outputs and options:
- $ info astscript-color-faint-gray
- Full Gnuastro manual/book:
- $ info gnuastro
If you couldn't find your answer in the manual, you can get direct help from experienced Gnuastro users and developers. For more information, please run:
- $ info help-gnuastro
astscript-color-faint-gray options:¶
- Input:
- -h, --hdu=STR
- HDU/extension for the input channels.
- -r, --reghdu=STR
- HDU/extension for the regions image.
-g, --globalhdu=STR/INT Use this HDU for all inputs, ignore '--hdu'.
- -w, --weight=FLT
- Relative weight for each input channel.
- -m, --minimum=FLT
- Minimum value for each input channel.
- -z, --zeropoint=FLT
- Zero point magnitude of each input channel.
- Asinh scaling parameters
- -Q, --qbright=FLT
- Parameter for bringing out brighter features.
- -s, --stretch=FLT
- Linear stretching parameter for faint features.
- Contrast, bias, and marks
- -b, --bias
- Constant (bias) to add to all the pixels (linear).
- -c, --contrast
- Change the contrast of the final image (linear).
- -G, --gamma
- Gamma (nonlinear, overrides bias/contrast).
- --markoptions=STR
- Options to add marks (passed to ConvertType).
- Color and gray parameters
- --coloronly
- No grayscale regions, background in color (black).
- --regions=STR
- Regions labeled image (color=2, black=1, gray=0).
- --grayval=FLT
- Gray threshold (highest value to use grayscale).
- --colorval=FLT
- Color threshold (lowest value to have color).
- --graykernelfwhm=FLT
- Kernel FWHM for convolving the background image.
--colorkernelfwhm=FLT Kernel FWHM for color separation ref. image.
- Output:
- -k, --keeptmp
- Keep temporary/auxiliar files.
- -o, --output
- Output color image name.
- --checkparams
- Print distribution of values used to find params.
- Operating mode:
- -h, --help
- Print this help list.
- -q, --quiet
- Don't print the list.
- -V, --version
- Print program version.
- --cite
- BibTeX citation for this program.
Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.
GNU Astronomy Utilities home page: http://www.gnu.org/software/gnuastro/
REPORTING BUGS¶
Report bugs to bug-gnuastro@gnu.org.
COPYRIGHT¶
Copyright © 2021-2025, Free Software Foundation, Inc.
License GPLv3+: GNU General public license version 3 or later.
This is free software: you are free to change and redistribute it. There is NO
WARRANTY, to the extent permitted by law.
Written/developed by Raul Infante-Sainz and Mohammad Akhlaghi.
SEE ALSO¶
The full documentation for astscript-color-faint-gray is maintained as a Texinfo manual. If the info and astscript-color-faint-gray programs are properly installed at your site, the command
- info astscript-color-faint-gray
should give you access to the complete manual.
| November 2025 | GNU Astronomy Utilities 0.24 |