Manual: pgmmorphconv

Pgmmorphconv User Manual(1)			   General Commands Manual			 Pgmmorphconv User Manual(1)

NAME
       pgmmorphconv - perform morphological convolutions: dilation, erosion

SYNOPSIS
       pgmmorphconv [
	-erode |
	-dilate |
	-open |
	-close |
	-gradient ] templatefile [pgmfile]

       Minimum	unique	abbreviation of option is acceptable.  You may use double 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.

DESCRIPTION
       This program is part of Netpbm(1).

       pgmmorphconv performs morphological convolutions on a PGM image: dilation and erosion.

       pgmmorphconv performs a "topological" convolution.  For each pixel of the input,	 pgmmorphconv  generates  an  output
       pixel  in  the  same  position.	To determine the intensity of the output pixel, pgmmorphconv lays the template image
       over the input image such that the middle pixel of the template is over the input pixel	in  question.	pgmmorphconv
       looks  at the input pixels underneath each white pixel in the template.	For a dilation, the maximum intensity of all
       those pixels is the intensity of the output pixel.  For an erosion, it is the minimum.

       Thus, the dilation effect is that bright areas of the input get bigger and dark areas smaller.  The erosion effect is
       the opposite.  The simplest template image would be one with a white pixel in the middle and the	 rest  black.	This
       would  produce  an output image identical to the input.	Another simple template image is a fully white square.	This
       causes bright or dark areas to expand in all directions.	 A template image that is white on the left side  and  black
       on the right would smear the image to the right.

       The  template  file  named by templatefile contains the template image as a PBM image.  It must have an odd number of
       rows and an odd number of columns, so there is a definite middle pixel.	It must contain at least one white pixel.

       This is similar to the continuous convolution done by pnmconvol, except that with pnmconvol the output intensity is a
       weighted average of nearby input pixels instead of a minimum or maximum.

       This convolution changes the three Minkowski integrals in a predefined way, and can be used to filter an image to en‐
       hance certain features, to ease their automatic recognition.

OPTIONS
       In addition to the options common to all programs based on libnetpbm (most notably -quiet, see  Common Options ), pg‐
       mmorphconv recognizes the following command line options:

       The options -erode and -dilate obviously produce an erosion or dilation, respectively.

       The -open option causes pgmmorphconv to perform first an erode and then a dilate operation.  The -close option causes
       a dilate first and then an erode.  If you specify none of these options, it is the same as -dilate.

       With -gradient, pgmmorphconv produces an image which is the difference between the eroded image and the	dilated	 im‐
       age.  -gradient was new in Netpbm 10.70 (March 2015).

SEE ALSO
       •      pgmminkowski(1)

       •      pnmconvol(1)

       •      pgm(1)

       For more information about morphological convolutions, see e.g.

       •       J.S.  Kole,  K.	Michielsen,  and H. De Raedt, "Morphological Image Analysis of Quantum Motion in Billiards",
	      Phys. Rev. E 63, 016201-1 - 016201-7 (2001)

       •      K. Michielsen and H. De Raedt, "Integral-Geometry Morphological  Image  Analysis",  Phys.	 Rep.  347,  461-538
	      (2001).

AUTHORS
       Luuk van Dijk, 2001.

       Based on work which is Copyright (C) 1989, 1991 by Jef Poskanzer.

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/pgmmorphconv.html

netpbm documentation					29 March 2015				 Pgmmorphconv User Manual(1)