man > pamsummcol(1)

Pamsummcol User Manual(1)              General Commands Manual             Pamsummcol User Manual(1)

NAME
       pamsummcol - summarize (sum, average, etc) a Netpbm image by column


SYNOPSIS
       pamsummcol { -sum | -mean | -min | -max } [imagefile]

       All  options can be abbreviated to their shortest unique prefix.  You may use two hyphens in‐
       stead 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).

       pamsummcol  reads  a  Netpbm  image (PNM or PAM) and performs a summary function over all the
       rows in each column (sum, mean, etc.).  It produces an image of the same kind that  the  same
       width and depth as the input, and one row high.  Its sample values are the result of the sum‐
       mary.

       pamsummcol performs the summary operation on each plane independently.

       pamsummcol  performs  the operation on the actual sample values, not on the light intensities
       represented by them in the case that the image is a PGM or PPM image.

       If you want to summarize by row instead of by column, run the  input  through  pamflip  first
       (and  if  you  want  the  output  to  be a single column instead of a single row, use pamflip
       again).

       If you want to summarize over the entire image (getting a one-tuple output image),  use  pam‐
       summ to get a summary row, pamflip to turn that into a column, the pamsumm again to summarize
       the column.

       If  you want to summarize the individual samples in an entire image, instead of by tuple, use
       pamsumm.

       pamsummcol performs the operation on the actual sample values, not on the  light  intensities
       represented  by them in the case that the image is a PGM or PPM image or PAM equivalent.  You
       can use pnmgamma to convert such an image to one with samples proportional  to  light  inten‐
       sity, and then use pamsummcol on the result.

       You can achieve the same thing as pamsummcol -mean with pamscale.  Just scale vertically to a
       single row, without scaling horizontally at all.  Use the pixel mixing method.


OPTIONS
       In  addition  to  the options common to all programs based on libnetpbm (most notably -quiet,
       see ]8;;index.html#commonoptions\ Common Options]8;;\ ), pamsummcol 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.
                   In each column and plane of the output row, the sample value is the
                   sum of all the samples values in the same column and plane of the input.
                   If a result is greater than the image maxval, it is clipped to
                   the maxval.


       -mean

              This option makes the summary function arithmetic mean.
                   In each column and plane of the output row, the sample value is the
                   mean of all the samples values in the same column and plane of the input.


       -min

              This option makes the summary function arithmetic minimum.
                   In each column and plane of the output row, the sample value is the
                   minimum of all the samples values in the same column and plane of
                   the input.


       -max

              This option makes the summary function arithmetic maximum.
                   In each column and plane of the output row, the sample value is
                   the maximum of all the samples values in the same column and
                   plane of the input.




SEE ALSO
       pamsumm(1), pamflip(1), pamfunc(1), pamarith(1), pamscale(1), pam(1),


HISTORY
       pamsummcol 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/pamsummcol.html

netpbm documentation                       25 January 2009                 Pamsummcol User Manual(1)