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 ⟨index.html#commonoptions⟩ ), 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

       pamsummcol(1), pam(1),

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

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