Pamgauss UserManual(0)Pamgauss UserManual(0)

pamgauss - create a two dimensional gaussian function as a PAM image

pamgauss-width-height-sigma=number[-maxval=number] [-tuple-type=string] Minimum unique abbreviation of option is acceptable. You may use dou- ble 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.

pamgauss 3 3 -sigma=.5 -tupletype=GRAYSCALE | pamtopnm >gauss.pgm pnmconvol -nooffset gauss.pgm myimage.ppm >blurred.ppm

This program is part ofNetpbm(1).pamgaussgenerates 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. The values are scaled so that the area under the surface of the two- dimensional Gaussian function is the maxval of the image. You can use this image, converted to PGM, as a convolution kernel withpnmconvolto blur an image. (This technique is known as Gaussian blur- ring).widthandheightare the dimensions of the image thatpamgaussgener- ates. Mathematically speaking, they are the domain of the two dimen- sional gaussian function. 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. If you want to be sure you get a whole Gaussian function, make sure that you choose a sigma and image dimen- sions so that if you made it any larger, the sample values at the edges would be zero. The output image is PAM. To turn it into a PGM that you can use withpnmconvol, specify-tupletype=GRAYSCALEand pass the output throughpamtopnm. You must use the-nooffsetoption onpnmconvolbecause zero means zero in the PAM thatpamgaussgenerates.

This program is part ofNetpbm(1).-sigma=numberThis is the sigma parameter of the Gaussian function (if it were a Gaussian probability function, this would be its the standard deviation). 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.numberis in units of pixels. This option is required. There is no default.-maxval=numberThis is the maxval for the output image. It defaults to 255.-tupletype=stringThis is the value of the "tuple_type" attribute of the created PAM image. It can be any string up to 255 characters. If you don’t specify this,pamgaussgenerates a PAM with unspecified tuple type.

pnmconvol(1),pamtopnm(1),pgmkernel(1),pamseq(1),pam(1)

pamgausswas new in Netpbm 10.23 (July 2004). netpbm documentation 8 May 2004 Pamgauss UserManual(0)

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