# pnmsmooth(1) - man - phpman

> **TLDR:** Smooth out a PNM image.
>
- Smooth out a PNM image using a convolution matrix of size 3x3:
  `pnmsmooth {{path/to/input.pnm}} > {{path/to/output.pnm}}`
- Smooth out a PNM image using a convolution matrix of size width times height:
  `pnmsmooth {{-w|-width}} {{width}} {{-h|-height}} {{height}} {{path/to/input.pnm}} > {{path/to/output.pnm}}`

*Source: tldr-pages*

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[pnmsmooth(1)](https://www.chedong.com/phpMan.php/man/pnmsmooth/1/markdown)                           General Commands Manual                          [pnmsmooth(1)](https://www.chedong.com/phpMan.php/man/pnmsmooth/1/markdown)



## NAME
       pnmsmooth - smooth out an image

## SYNOPSIS
       **pnmsmooth** [**-size** _width_ _height_] [**-dump** _dumpfile_] [_pnmfile_]

## DESCRIPTION
       Smooths  out  an  image by replacing each pixel with the average of its width X height neigh‐
       bors.  It is implemented as a C progam that generates a PGM convolution matrix and  then  in‐
       vokes _pnmconvol_.

## OPTIONS
### -size width height
              Specifies  the  size  of the convolution matrix.  Default size is a 3x3 matrix.  Width
              and height sizes must be odd.  Maximum size of convolution matrix is  limited  by  the
              maximum  value  for a pixel such that (width * height * 2) must not exceed the maximum
              pixel value.

### -dump dumpfile
              Generates and saves the convolution file only.  Use of this option does not invoke pn‐
              mconvol.

## SEE ALSO
       [pnmconvol(1)](https://www.chedong.com/phpMan.php/man/pnmconvol/1/markdown), [pnm(5)](https://www.chedong.com/phpMan.php/man/pnm/5/markdown)

## AUTHORS
       Copyright (C) 1989, 1991 by Jef Poskanzer.
       Converted from script to C program December 1994 by Mike Burns (<burns@chem.psu.edu>).



                                           4 December 1994                              [pnmsmooth(1)](https://www.chedong.com/phpMan.php/man/pnmsmooth/1/markdown)