Pamgauss User Manual(0)				       Pamgauss User Manual(0)



NAME
       pamgauss - create a two dimensional gaussian function as a PAM image


SYNOPSIS
       pamgauss	  width	  height   -sigma=number   [-maxval=number]   [-tuple-
       type=string]

       Minimum unique abbreviation of option is acceptable.  You may use  dou-
       ble  hyphens  instead  of single hyphen to denote options.  You may use
       white space in place of the equals sign to separate an option name from
       its value.



EXAMPLES
	    pamgauss 3 3 -sigma=.5 -tupletype=GRAYSCALE | pamtopnm >gauss.pgm
	    pnmconvol -nooffset gauss.pgm myimage.ppm >blurred.ppm


DESCRIPTION
       This program is part of Netpbm(1).

       pamgauss	 generates  a one-plane PAM image whose samples are a gaussian
       function of their distance from the center of  the  image.   I.e.   the
       sample  value  is  highest in the center and goes down, in a bell curve
       shape, as you move away from the center.

       The values are scaled so that the volume under the surface of the  two-
       dimensional Gaussian function is the maxval of the image.

       You  can	 use this image as a convolution kernel with pnmconvol to blur
       an image.  (This technique is known as Gaussian blurring).

       width and height are the dimensions of the image that  pamgauss	gener-
       ates.   Mathematically  speaking, they are the domain of the two dimen-
       sional gaussian function.

       The sum of all the samples is  equal  to	 the  image's  maxval  (within
       rounding	 error).   This is true even if you clip the Gaussian function
       by making the image too small.  If you want to be sure you get a	 whole
       Gaussian	 function,  make sure that you choose a sigma and image dimen-
       sions so that if you made it any larger, the sample values at the edges
       would be zero.

       The  output  image  is  PAM.  To make it usable with pnmconvol, specify
       -tupletype=GRAYSCALE so pnmconvol can use it as if it  were  PGM.   You
       must  use  the -nooffset option on pnmconvol because zero means zero in
       the PAM that pamgauss generates.


OPTIONS
       -sigma=number
	      This is the sigma parameter of the Gaussian function (if it were
	      a	 Gaussian  probability	function,  this	 would be its standard
	      deviation).  The higher the number,  the	more  spread  out  the
	      function	is.  Normally, you want to make this number low enough
	      that the function reaches zero value before  the	edge  of  your
	      image.

	      number is in units of pixels.

	      This option is required.	There is no default.


       -maxval=number
	      This is the maxval for the output image.	It defaults to 255.


       -tupletype=string
	      This  is	the value of the "tuple_type" attribute of the created
	      PAM image.  It can be any string up to 255 characters.   If  you
	      don't  specify  this,  pamgauss generates a PAM with unspecified
	      tuple type.




SEE ALSO
       pnmconvol(1), pamtopnm(1), pgmkernel(1), pamseq(1), pam(1)


HISTORY
       pamgauss was new in Netpbm 10.23 (July 2004).



netpbm documentation		  8 May 2004	       Pamgauss User Manual(0)