Penguin
Recent Changes
Blame: pgmkernel(1)
EditPageHistoryDiffInfoLikePages
Annotated edit history of pgmkernel(1) version 1, including all changes. View license author blame.
Rev Author # Line
1 perry 1 pgmkernel
2 !!!pgmkernel
3 NAME
4 SYNOPSIS
5 DESCRIPTION
6 OPTIONS
7 BUGS
8 SEE ALSO
9 AUTHOR
10 ----
11 !!NAME
12
13
14 pgmkernel - generate a convolution kernel
15 !!SYNOPSIS
16
17
18 __pgmkernel__ [[ __-weight__ ''w'' ] ''width'' [[
19 ''height'' ]
20 !!DESCRIPTION
21
22
23 Generates a portable graymap array of size ''width'' x
24 ''height'' (or ''width'' x ''width'' if
25 ''height'' is not specified) to be used as a convolution
26 file by __pnmconvol__. The data in the convolution array
27 K are computed according to the formula:
28
29
30 K(i,j) = 1 / ( 1 + w * sqrt((i-width/2)^2 +
31 (j-height/2)^2))
32
33
34 where ''w'' is a coefficient specified via the
35 ''-weight'' flag, and ''width'' and ''height'' are
36 the X and Y filter sizes.
37
38
39 The output PGM file is always written out in ASCII
40 format.
41 !!OPTIONS
42
43
44 The optional ''-weight'' flag should be a real number
45 greater than -1. The default value is 6.0.
46 !!BUGS
47
48
49 The computation time is proportional to ''width'' *
50 ''height''. This increases rapidly with the increase of
51 the kernel size. A better approach could be using a FFT in
52 these cases.
53 !!SEE ALSO
54
55
56 pnmconvol(1), pnmsmooth(1)
57 !!AUTHOR
58
59
60 Alberto Accomazzi (alberto@cfa.harvard.edu).
61 ----
This page is a man page (or other imported legacy content). We are unable to automatically determine the license status of this page.