pamsummcol



Pamsummcol User Manual(0)                            Pamsummcol User Manual(0)




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 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).

       pamsummcol  reads  a  Netpbm  image (PNM or PAM) and performs a summary
       function over all the rows in each column (sum, mean, etc.).   It  pro-
       duces  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 instead of over  columns
       separately, 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 intensity,  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

       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), pamscale(1), pamfunc(1), pamarith(1), pamscale(1), pam(1),



HISTORY

       pamsummcol was added to Netpbm in Release 10.21 (March 2004).



netpbm documentation           07 February 2004      Pamsummcol User Manual(0)

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