Ubuntu Manpage: pammixmulti - blend together multiple PAM images

Provided by: netpbm_11.05.02-1.1build1_amd64

NAME

       pammixmulti - blend together multiple PAM images

SYNOPSIS

       pammixmulti
         [--blend=average|random|mask]
         [--maskfile=filename]
         [--stdev=number]
         [--randomseed integer]
         filename ...

       Minimum  unique  abbreviation  of  an option is acceptable. You can use a single hyphen instead of double
       hyphens to denote options. You can use white space in place of the equals sign to separate an option name
       from its value.

DESCRIPTION

       This file is part of Netpbm(1).

       pammixmulti mixes two or more images to produce a new  image.  The  program  provides  multiple  ways  to
       interpret "mix."

OPTIONS

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

--blend=average|random|mask

This option specifies how the input images should be mixed to produce the output image. With
--blend=average (the default), each pixel in the output is produced by averaging the corresponding
pixels from all the input images. With --blend=random, each pixel in the output is produced by
selecting the corresponding pixel from one of the input images, chosen at random on a per-pixel
basis. With --blend=mask, each pixel in the output is produced by a weighted average of the
corresponding pixels from all the input images based on the grayscale level of an additional mask
image.

--maskfile=filename

In conjunction with --blend=mask, this option names a grayscale mask file to control the blending
of each pixel. (If the file is not grayscale, the first channel is treated as gray). Where the
mask file is black, the first image is selected. Where the mask file is white, the last image is
selected. Intermediate levels of gray select intermediate images.

--stdev=number

When used with --blend=mask, this option controls how smoothly the various input images are mixed
to produce each output pixel. For example, consider running pammixmulti with three input images
and a mask image that uses gray levels from 0 to 255. Given --stdev=0.0, gray levels 0-84 produce
exclusively image 1; gray levels 85-170 produce exclusively image 2; and gray levels 171-255
produce exclusively image 3. If the argument to --stdev is positive, images are blended according
to a normal distribution. Hence, gray levels around 85 produce an output pixel that includes
roughly equal amounts of the corresponding pixel from images 1 and 2 but less of the corresponding
pixel from image 3. As number tends towards the number of input images (going beyond that has
diminishing impact), the output tends to look more like --blend=average. number defaults to 0.25.

--randomseed integer
This is the seed for the random number generator used with --blend=random

Use this to ensure you get the same image on separate invocations.

ARGUMENTS

       You supply the names of the files to mix as non-option arguments.

EXAMPLES

       Average a bunch of PPM images to produce a new PAM image:
           pammixmulti input*.ppm >output.ppm

       Mix these same images by taking each pixel from a randomly selected input image:

           pammixmulti --blend=random input*.ppm >output.ppm

       Use a mask image to control the fading among input images on a pixel-by-pixel basis:

           pammixmulti --blend=mask --maskfile=mask.pgm >output.pam \
              one.pam two.pam three.pam four.pam

       Do the same but with more abrupt transitions:

           pammixmulti --blend=mask --maskfile=mask.pgm --stdev=0.0 >output.pam \
              one.pam two.pam three.pam four.pam

       and now with more gradual transitions:

           pammixmulti --blend=mask --maskfile=mask.pgm --stdev=1.0 >output.pam \
              one.pam two.pam three.pam four.pam

HISTORY

       pammixmulti was new in Netpbm 10.85 (December 2018).

AUTHOR

       Copyright 2018 Scott Pakin, scott+pbm@pakin.org.

DOCUMENT SOURCE

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

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

netpbm documentation                            18 November 2018                      Pammixmulti User Manual(1)