pamaddnoise - add noise to a Netpbm image

       Copyright (C) 1995 by Mike Burns <burns@cac.psu.edu>

       This program is part of Netpbm(1).

       pamaddnoise  adds  the  specified  noise  type  to  a  Netpbm image.  pamaddnoise treats a PPM image as 3
       independent planes, not as a plane of colors in a color space.

       This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The  master  documentation
       is at

              http://netpbm.sourceforge.net/doc/pamaddnoise.html

netpbm documentation                             21 August 2023                       PamaddnoiseUserManual(1)

pamaddnoise was added to Netpbm in Version 10.29 (August 2005).  It had been distributed  by  Mike  Burns
       via his own web site before that (and continued to be so).

       Burns'  version,  and  the one in Netpbm 10.29, was called pnmaddnoise and worked only on PNM images.  In
       Netpbm 10.30, it was converted to handle PAM images and renamed to pamaddnoise.

       pamaddnoise - add noise to a Netpbm image

       In addition to the options common to all programs based on libnetpbm (most notably  -quiet,  see   Common
       Options ), pamaddnoise recognizes the following command line options:

       -typenoise_type
              Select   type   of   noise   by   name.   The  following  noise  types  are  available:  gaussian,
              multiplicative_gaussian, impulse, laplacian, poisson.   Only  enough  letters  to  be  unique  are
              required for the noise type option.  The default noise type is gaussian.

       gaussian

              To each sample value is added the value of a two Gaussian random variables.
                  The variance of one is independent of the sample value, while the variance
                  of the other is proportional to the sample value.  You control these
                  variances with options -sigma1 and -sigma2 (and can eliminate
                  either by setting the variance to 0).  The mean of the Gaussian
                  distributions is 0.

       multiplicative_gaussianimpulse

              This is 'salt and pepper' noise.  Samples are changed randomly
                  to zero or full brightness or left alone.  This is also know as salt and
                  pepper noise, as in a grayscale picture, it adds white pixels and black
                  pixels, which look like salt and pepper, respectively.  Control this with
                  options -tolerance and -salt.

       laplacianpoisson-lambdavalue
              This is valid only with -type=poisson.  It is the expected value of the Poisson distribution for a
              sample value of maximum intensity.  The expected value for other intensities is proportional; e.g.
              for half intensity, it is half this value.

              The default value is 12.

       -lsigmavalue
              This is meaningful only for laplacian noise.

              The default value is 10.0.

       -mgsigmavalue
              This is valid only for multiplicative gaussian noise.

              The default value is 0.5.

       -seedint
              This is the random number generator seed value.  Use this to get
                repeatable results.

       -sigma1value
              This is valid only for gaussian noise.  It is the standard deviation
                of the Gaussian random variable that is multiplied by the square root of
                each sample value and added to that sample value.

                  The default value is 4.0.

       -sigma2value
              This is valid only for gaussian noise.
                It is the standard deviation of the Gaussian random variable that is
                added directly to each sample value.

              The default value is 20.0.

       -tolerancefraction
              This is valid only for impulse noise.
                fraction is the fraction of samples that are changed
                in the output.  Whether each is changed to salt or pepper is controlled by
                -salt.

              The default value is 0.10.

       -salt=fraction

              This is valid only for impulse noise.  fraction is the
                  fraction of the pixels that are changed that are changed to salt (maxval);
                  the rest are changed to pepper (0).

              The default is 0.5 (half salt, half pepper).

              This option was new in Netpbm 11.04 (September 2023).  Before that, the
                noise is always half salt and half pepper.

       •      "Adaptive  Image  Restoration  in  Signal-Dependent  Noise" by R. Kasturi Institute for Electronic
              Science, Texas Tech University, 1982

       •      "Digital Image Processing Algorithms" by Ioannis Pitas, Prentice Hall, 1993 ISBN 0-13-145814-0

pgmnoise(1), pgmmedian(1), pnm(1), pam(1),

pamaddnoise { [-typegaussian]

       [-sigma1value]

       [-sigma2value] | -typemultiplicative_gaussian

       [-mgsigmavalue] | -typeimpulse

       [-toleranceratio] | -typelaplacian

       [-lsigmavalue] | -typepoisson

       [-lambdavalue] } [-seedint]

       [netpbmfile]