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 (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, 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		25 January 2009	     Pamsummcol User Manual(0)