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CONVOLVE(1) User Commands CONVOLVE(1)


Convolve - convolve an image with a given kernel


astconvolve [OPTION...] ASTRdata


Convolve is part of GNU Astronomy Utilities 0.8. Convolve will convolve an input image with a given spatial kernel (image) in the spatial domain (no edge effects) or frequency domain. The latter suffers from edge effects, but can be much faster.

For more information, please run any of the following commands. In particular the second contains a very comprehensive explanation of Convolve's invocation: expected input(s), output(s), and a full description of all the options.

All options and their values:
$ astconvolve -P
Inputs/Outputs and options:
$ info astconvolve
Full section in manual/book:
$ info Convolve
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

Convolve options:

-c, --column=STR
Column name or number if input is a table.
-h, --hdu=STR/INT
Extension name or number of input data.
-H, --minsharpspec=FLT
Deconvolution: min spectrum of sharp img.
-k, --kernel=STR
File name of kernel for convolution.
Column name or number if kernel is a table.
Do not flip the kernel image.
Do not normalize the kernel image.
Select column(s): `name', `unit', `comment'.
Micro-seconds to wait for standard input.
-u, --khdu=STR
HDU containing the kernel.
Tessellation (tile grid):
Tile IDs in an image, the size of input.
-F, --remainderfrac=FLT
Fraction of remainder to split last tile.

-M, --numchannels=INT[,..] No. of channels in dim.s (FITS order).

Display 1 element/tile, not full input res.
Work (not tile) over channel edges.
-Z, --tilesize=INT[,INT]
Regular tile size on dim.s (FITS order).
-C, --checkfreqsteps
View the steps in the frequency domain.
-D, --dontdelete
Don't delete output if it exists.
-K, --keepinputdir
Keep input directory for automatic output.
Do not correct the edges in the spatial domain
-o, --output=STR
Output file name.
Table format: `fits-ascii', `fits-binary'.
-T, --type=STR
Type of output: e.g., int16, float32, etc...
Operating modes:
-?, --help
give this help list
BibTeX citation for this program.
Read configuration file STR immediately.
-d, --domain=STR
Convolution domain: `spatial', `frequency'.
Do not parse any more configuration files.
-m, --makekernel=INT
Make 2*INT kernel to create input image.
Minimum bytes in array to not use ram RAM.
-N, --numthreads=INT
Number of CPU threads to use.
Only run if the program version is STR.
-P, --printparams
Print parameter values to be used and abort.
-q, --quiet
Only report errors, remain quiet about steps.
-S, --setdirconf
Set default values for this directory and abort.
give a short usage message
-U, --setusrconf
Set default values for this user and abort.
-V, --version
print program version

Mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options.

GNU Astronomy Utilities home page:


Report bugs to


Copyright © 2015-2018, 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 Mohammad Akhlaghi


The full documentation for Convolve is maintained as a Texinfo manual. If the info and Convolve programs are properly installed at your site, the command
info Convolve

should give you access to the complete manual.

December 2018 GNU Astronomy Utilities 0.8