pnmsmooth1

Usage

Overview

This program is part of Netpbm(1) .

pnmsmooth smoothes out an image by replacing each pixel with the average of its width X height neighbors. It is implemented as a program that invokes pnmconvol with an appropriate convolution matrix.

Options

In addition to the options common to all programs based on libnetpbm (most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), pnmsmooth recognizes the following command line options:

-width=cols

-height=rows

These options specify the dimensions of the convolution matrix. Default dimensions are 3 wide and 3 high.

Before Netpbm 10.49 (December 2009), the maximum size of the convolution matrix is limited by the maxval of the image such that width * height * 2 must not exceed the maxval. (use pamdepth to increase the maxval if necessary).

These options were new in Netpbm 10.32 (February 2006). Before that, use -size.

-size

This deprecated option exists in current Netpbm for backward compatibility. It was obsoleted by -width and -height in Netpbm 10.32 (February 2006).

When you use this option, the first two program arguments are the width and height, respectively, of the convolution matrix and do the same thing as the -width and -height option values. The third (optional) program argument is the input file name.

In reality, in old pnmsmooth, the width and height are two values of the -size option, but the modern Netpbm command syntax paradigm doesn't allow an option with multiple values, so instead -size is an option with no value and width and height are program arguments. That has the fortunate effect of making the following command mean the same in current pnmsmooth as in old pnmsmooth:

     pnmsmooth -size 5 5 infile.ppm >outfile.ppm

-dump=dumpfile

This options makes pnmsmooth only show you the convolution matrix. It writes to Standard Output a pnmconvol -matrix option value that represents the matrix. It does not invoke pnmconvol and does not produce an output image.

Before Netpbm 10.49 (December 2009), this option is rather different. It takes a file name as a value, and it writes to that file the convolution matrix as a PGM file (as used to be the normal input for pnmconvol).

Document source

This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at

http://netpbm.sourceforge.net/doc/pnmsmooth.html