NAME
pamsumm - Summarize the samples in a Netpbm image arithmetically
SYNOPSIS
pamsumm { -sum | -mean | -min | -max } [-normalize] [-brief] [imagefile]
All options can be abbreviated to their shortest unique prefix. You may use two hyphens instead of one. You may separate an option name and its value with white space instead of an equals sign.
DESCRIPTION
This program is part of Netpbm(1).
pamsumm reads a Netpbm image (PNM or PAM) and performs a summary function over all the samples in all the rows, columns, and planes and prints the result to Standard Output.
pamsumm performs the operation on the actual sample values. In the case of a PGM or PPM or PAM equivalent (i.e. a visual image), this is not the same as the light intensities represented by those samples. See the format specifications of PGM(1), PPM(1), and PAM(1), for the precise meanings of samples in these formats. If you want to do arithmetic on light intensities of such a visual image, you can use pnmgamma to convert it to one with samples proportional to light intensity, and then use pamsumm on the result.
If you want to summarize by column (e.g. add up the columns separately), use pamsummcol. If you want to summarize by row, use a combination of pamsummcol and pamflip. If you want to summarize a particular plane, use pamchannel to extract it and then pamsumm.
OPTIONS
In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options ), pamsumm recognizes the following command line options:
You must specify exactly one of -sum, -mean, -min, or -max.
|
-sum |
This option makes the summary function addition. | ||
|
-mean |
This option makes the summary function arithmetic mean. | ||
|
-min |
This option makes the summary function arithmetic minimum. | ||
|
-max |
This option makes the summary function arithmetic maximum. |
-normalize
This option
causes each sample to be normalized to a fraction
(in the range 0..1) so the result is independent of the
image’s
maxval. E.g. if you request the mean of an image which has
maxval
200 and all the samples have value 50, pamsumm will
give you
50 as an answer. But pamsumm -normalize will give you
.25.
If instead you
want a result that is independent of maxval but still
in integers, you can use pamdepth to convert the
input to some
standard maxval and not use -normalize. For example,
if you want
the mean brightness of a PPM image, on a scale of 0 to 99,
do
pamdepth 99 myimage.ppm | pamsumm -mean
This option was new in Netpbm 10.22 (April 2004)
|
-brief |
This option causes pamsumm to display the answer as a bare |
number, rather than in a complete sentence.
This option was new in Netpbm 10.22 (April 2004)
SEE ALSO
HISTORY
pamsumm was added to Netpbm in Release 10.21 (March 2004).
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool ’makeman’ from HTML source. The master documentation is at