---
name: "ficombine"
section: "1"
platform: "linux"
package: "fitsh"
version: "0.9.4-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/ficombine"
---

# ficombine(1)

combining (most frequently, averaging) a set of images

## NAME

ficombine - combining (most frequently, averaging) a set of images

## SYNOPSIS

**ficombine** \[*options*\] *\<input images\>* \[*-o\|--output \<output\>*\]

## DESCRIPTION

The purpose of this program is to combine the input images (with the same sizes) to a single image. This combination refers to a kind of "averaging" for the images, however, other modes are also available.

## 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.

- **-o**, **--output** \<fits\>

  The name of the output file (omitting or specifing '-' yields the output to be written to stdout).

- **--history**, **--no-history**

  Incude or exclude the command line of the invoking \`ficombine\` call. By default, the command line is added into the FITS headers (FI\_HSTRY) but if there are enormous amount of input files, one can use **--no-history** to omit the respective lengthy keywords.

- **--data** \<spec\>

  Output pixel data format specification.

- **-b**, **--bitpix** \<bitpix\>

  Standard FITS output bitpix value.

- **-M**, **--input-mask** \<fits\>

  Input mask file to co-add to output image.

### Generic combination specification:

- **-m**, **--mode** \<mode\>

  Use the specified mode to combine images.

- **-n**, **--ignore-negative**

  Ignore (i.e. mask) pixels with negative values.

- **--logical-or**

  Use logical "or" combination between masks.

- **--logical-and**

  Use logical "and" combination between masks.

### Combination modes (a comma-separated list of these should follow -m\|--mode):

- mean

  The mean value of the pixels.

- median

  The median value of the pixels.

- min, minimum

  The minimum value of the pixels.

- max, maximum

  The maximum value of the pixels.

- rejmed, rejection

  Median value after rejecting outliers.

- rejmean

  Mean value after rejecting outliers.

- iterations=\<n\>

  Number of iterations to reject outliers.

- lower=\<l\>, upper=\<u\>, sigma=\<s\>

  Outlier limit (lower, upper, both) in standard deviation. Note that setting sigma to some value is equivalent to setting 'lower' and 'upper' to the same value simultaneously.

- truncated

  Truncated mean.

- winsorized

  Winsorized mean.

- lowest=\<cnt\>, highest=\<cnt\>, discard=\<cnt\>

  Reject the 'lowest' and 'highest' count of points when computing truncated or winsorized mean. Setting 'discard' to some value is equivalent to setting 'lowest' and 'highest' to this value simultaneously.

- sum

  Sum of the pixel values.

- squaresum

  Sum for the squarers of the pixel values.

- scatter, stddev

  Pixel scatter (standard deviation).

- or

  Use logical "or" combination between masks.

- and

  Use logical "and" combination between masks.

- ignorenegative

  Ignore (i.e. mask) pixels with negative values.

- ignorezero

  Ignore (i.e. mask) pixels with a zero value.

- ignorenegative

  Ignore (i.e. mask) pixels with positive values.

## REPORTING BUGS

Report bugs to \<apal@szofi.net\>, see also https://fitsh.net/.

## COPYRIGHT

Copyright © 1996, 2002, 2004-2008, 2010-2016, 2018-2020; Pal, Andras \<apal@szofi.net\>