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diff --git a/upstream/opensuse-tumbleweed/man1/pamgauss.1 b/upstream/opensuse-tumbleweed/man1/pamgauss.1 new file mode 100644 index 00000000..0c9341bf --- /dev/null +++ b/upstream/opensuse-tumbleweed/man1/pamgauss.1 @@ -0,0 +1,182 @@ +\ +.\" This man page was generated by the Netpbm tool 'makeman' from HTML source. +.\" Do not hand-hack it! If you have bug fixes or improvements, please find +.\" the corresponding HTML page on the Netpbm website, generate a patch +.\" against that, and send it to the Netpbm maintainer. +.TH "Pamgauss User Manual" 0 "18 May 2017" "netpbm documentation" + +.SH NAME +\fBpamgauss\fP - create a two-dimensional Gaussian function as a PAM image + +.UN synopsis +.SH SYNOPSIS + +\fBpamgauss\fP +\fIwidth\fP +\fIheight\fP +\fB-sigma=\fP\fInumber\fP +[\fB-maxval=\fP\fInumber\fP] +[\fB-tupletype=\fP\fIstring\fP] +[\fB-maximize\fP] +[\fB-oversample=\fP\fInumber\fP] +.PP +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. + + +.UN examples +.SH EXAMPLES + +.nf + pamgauss 7 7 -sigma=.5 -maximize -tupletype=GRAYSCALE | pamtopnm >gauss.pgm + pnmconvol -nooffset -normalize gauss.pgm myimage.ppm >blurred.ppm + +.fi + +.UN description +.SH DESCRIPTION +.PP +This program is part of +.BR "Netpbm" (1)\c +\&. +.PP +\fBpamgauss\fP 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. +.PP +You can use this image as a convolution kernel with +\fBpnmconvol\fP to blur an image. (This technique is known as +Gaussian blurring). + +\fIwidth\fP and \fIheight\fP are the dimensions of the image that +\fBpamgauss\fP generates. Mathematically speaking, they are the domain of +the two-dimensional Gaussian function. If you want to be sure you get a whole +Gaussian function, make sure that you choose a standard deviation and image +dimensions so that if you made it any larger, the sample values at the edges +would be zero. +.PP +The output image is PAM. To make it usable with \fBpnmconvol\fP, +specify \fB-tupletype=GRAYSCALE\fP so \fBpnmconvol\fP can use it as +if it were PGM. You must use the \fB-nooffset\fP option on +\fBpnmconvol\fP because zero means zero in the PAM that +\fBpamgauss\fP generates. +.PP +Without \fB-maximize\fP, 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. This is what is normally +required of a convolution kernel. +.PP +\fBpamgauss\fP oversamples and averages to represent the continuous +Gaussian function in discrete samples in the PAM output. Consider an image 11 +samples wide and an oversampling factor of 10. The samples can be thought of +as contiguous squares one unit wide. The center of the image is thus the +center of the 6th sample from the left. The 3rd sample from the left covers a +range of distances from 3 to 4 units from the center of the image. Because +the oversampling factor is 10, \fBpamgauss\fP computes the value of the +Gaussian function at 10 points evenly spaced between 3 and 4 units from the +center of the image and assigns the 3rd sample from the left the mean of those +10 values. + + +.UN options +.SH OPTIONS +.PP +In addition to the options common to all programs based on libnetpbm +(most notably \fB-quiet\fP, see +.UR index.html#commonoptions + Common Options +.UE +\&), \fBpamgauss\fP recognizes the following +command line options: + + +.TP +\fB-sigma=\fP\fInumber\fP +This is the standard deviation of the Gaussian function. 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. +.sp +\fInumber\fP is in units of samples. +.sp +This option is required. There is no default. + +.TP +\fB-maximize\fP +Causes \fBpamgauss\fP to use the whole dynamic range available in +the output PAM image by choosing an amplitude for the Gaussian function that +causes the maximum value in the image to be the maxval of the image. +.sp +If you select this, you probably want to normalize the output (scale the +samples down so the volume under the surface of the two-dimensional Gaussian +function is the maxval) before you use it, for example with +\fBpnmconvol\fP's \fB-normalize\fP option. The reason this is different +from just not using \fB-maximize\fP is that this subsequent normalization can +be done with much more precision than can be represented in a PAM image. +.sp +Without this option, \fBpamgauss\fP uses an amplitude that makes the volume +under the surface of the two-dimensional Gaussian function the maxval of the +image. This means all the samples in the image are normally considerably less +than the maxval. +.sp +This option was new in Netpbm 10.79 (June 2017). + +.TP +\fB-maxval=\fP\fInumber\fP +This is the maxval for the output image. 65535 is almost always the best +value to use. But there may be some programs (not part of Netpbm) that can't +handle a maxval greater than 255. +.sp +The default is 255. + +.TP +\fB-tupletype=\fP\fIstring\fP +This is the value of the "tuple_type" attribute of the created PAM image. +It can be any string up to 255 characters. +.sp +If you don't specify this, \fBpamgauss\fP generates a PAM with unspecified +tuple type. + +.TP +\fB-oversample=\fP\fInumber\fP +This sets the oversampling factor. \fBpamgauss\fP samples the Gaussian +function this many times, both horizontally and vertically, to get the value +of each sample in the output. +.sp +An oversampling factor of 1 means no oversampling, which means each +sample is based only on the value of the Gaussian function at the center of +the sample. +.sp +The default is 5 divided by the standard deviation, rounded up to a whole +number. +.sp +This option was new in Netpbm 10.79 (June 2017). Before that, it is +essentially 1 - there is no oversampling. + + + +.UN seealso +.SH SEE ALSO +.BR "pnmconvol" (1)\c +\&, +.BR "pamtopnm" (1)\c +\&, +.BR "pgmkernel" (1)\c +\&, +.BR "pamseq" (1)\c +\&, +.BR "pam" (5)\c +\& + +.UN history +.SH HISTORY +.PP +\fBpamgauss\fP was new in Netpbm 10.23 (July 2004). +.SH DOCUMENT SOURCE +This manual page was generated by the Netpbm tool 'makeman' from HTML +source. The master documentation is at +.IP +.B http://netpbm.sourceforge.net/doc/pamgauss.html +.PP
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