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pgmkernel(1) [minix man page]

pgmkernel(1)                                                  General Commands Manual                                                 pgmkernel(1)

pgmkernel - generate a convolution kernel SYNOPSIS
pgmkernel [ -weight w ] width [ height ] DESCRIPTION
Generates a portable graymap array of size width x height (or width x width if height is not specified) to be used as a convolution file by pnmconvol. The data in the convolution array K are computed according to the formula: K(i,j) = 1 / ( 1 + w * sqrt((i-width/2)^2 + (j-height/2)^2)) where w is a coefficient specified via the -weight flag, and width and height are the X and Y filter sizes. The output PGM file is always written out in ASCII format. OPTIONS
The optional -weight flag should be a real number greater than -1. The default value is 6.0. BUGS
The computation time is proportional to width * height. This increases rapidly with the increase of the kernel size. A better approach could be using a FFT in these cases. SEE ALSO
pnmconvol(1), pnmsmooth(1) AUTHOR
Alberto Accomazzi ( 10 December 1992 pgmkernel(1)

Check Out this Related Man Page

pnmsmooth(1)                                                  General Commands Manual                                                 pnmsmooth(1)

pnmsmooth - smooth out an image SYNOPSIS
pnmsmooth [-size width height] [-dump dumpfile] [pnmfile] DESCRIPTION
Smooths out an image by replacing each pixel with the average of its width X height neighbors. It is implemented as a C progam that gener- ates a PGM convolution matrix and then invokes pnmconvol. OPTIONS
-size width height Specifies the size of the convolution matrix. Default size is a 3x3 matrix. Width and height sizes must be odd. Maximum size of convolution matrix is limited by the maximum value for a pixel such that (width * height * 2) must not exceed the maximum pixel value. -dump dumpfile Generates and saves the convolution file only. Use of this option does not invoke pnmconvol. SEE ALSO
pnmconvol(1), pnm(5) AUTHORS
Copyright (C) 1989, 1991 by Jef Poskanzer. Converted from script to C program December 1994 by Mike Burns ( 4 December 1994 pnmsmooth(1)
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