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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 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 summary.

       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 pamsumm 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 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, with-
       out 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            25 January 2009      Pamsummcol User Manual(0)