1Pgmmorphconv User Manual(0) Pgmmorphconv User Manual(0)
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6 pgmmorphconv - perform morphological convolutions: dilation, erosion
7
10 pgmmorphconv [
11 -erode |
12 -dilate |
13 -open |
14 -close |
15 -gradient ] templatefile [pgmfile]
16 Minimum unique abbreviation of option is acceptable. You may use dou‐
18 ble hyphens instead of single hyphen to denote options. You may use
19 white space in place of the equals sign to separate an option name from
20 its value.
21
24 This program is part of Netpbm(1).
25 pgmmorphconv performs morphological convolutions on a PGM image: dila‐
27 tion and erosion.
28 pgmmorphconv performs a "topological" convolution. For each pixel of
30 the input, pgmmorphconv generates an output pixel in the same position.
31 To determine the intensity of the output pixel, pgmmorphconv lays the
32 template image over the input image such that the middle pixel of the
33 template is over the input pixel in question. pgmmorphconv looks at
34 the input pixels underneath each white pixel in the template. For a
35 dilation, the maximum intensity of all those pixels is the intensity of
36 the output pixel. For an erosion, it is the minimum.
37 Thus, the dilation effect is that bright areas of the input get bigger
39 and dark areas smaller. The erosion effect is the opposite. The sim‐
40 plest template image would be one with a white pixel in the middle and
41 the rest black. This would produce an output image identical to the
42 input. Another simple template image is a fully white square. This
43 causes bright or dark areas to expand in all directions. A template
44 image that is white on the left side and black on the right would smear
45 the image to the right.
46 The template file named by templatefile contains the template image as
48 a PBM image. It must have an odd number of rows and an odd number of
49 columns, so there is a definite middle pixel. It must contain at least
50 one white pixel.
51 This is similar to the continuous convolution done by pnmconvol, except
53 that with pnmconvol the output intensity is a weighted average of
54 nearby input pixels instead of a minimum or maximum.
55 This convolution changes the three Minkowski integrals in a predefined
57 way, and can be used to filter an image to enhance certain features, to
58 ease their automatic recognition.
59
62 In addition to the options common to all programs based on libnetpbm
63 (most notably -quiet, see
64 Common Options ⟨index.html#commonoptions⟩ ), pgmmorphconv recognizes
65 the following command line options:
66 The options -erode and -dilate obviously produce an erosion or dila‐
68 tion, respectively.
69 The -open option causes pgmmorphconv to perform first an erode and then
71 a dilate operation. The -close option causes a dilate first and then
72 an erode. If you specify none of these options, it is the same as -di‐
73 late.
74 With -gradient, pgmmorphconv produces an image which is the difference
76 between the eroded image and the dilated image. -gradient was new in
77 Netpbm 10.70 (March 2015).
78
81 •
82 pgmminkowski(1)
84 •
86 pnmconvol(1)
88 •
90 pgm(1)
92 For more information about morphological convolutions, see e.g.
95 •
98 J.S. Kole, K. Michielsen, and H. De Raedt, "Morphological Image
100 Analysis of Quantum Motion in Billiards", Phys. Rev. E 63,
101 016201-1 - 016201-7 (2001)
102 ⟨http://rugth30.phys.rug.nl/pdf/prechaos.pdf⟩
103 • K. Michielsen and H. De Raedt, "Integral-Geometry Morphological
105 Image Analysis", Phys. Rep. 347, 461-538 (2001).
106
112 Luuk van Dijk, 2001.
113 Based on work which is Copyright (C) 1989, 1991 by Jef Poskanzer.
115
117 This manual page was generated by the Netpbm tool 'makeman' from HTML
118 source. The master documentation is at
119 http://netpbm.sourceforge.net/doc/pgmmorphconv.html
121netpbm documentation 29 March 2015 Pgmmorphconv User Manual(0)