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 [AT] pakin.org.
SEE ALSO
pamcomp(1), ppmmix(1), pamarith(1), pnm(1), pam(1)
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DOCUMENT SOURCE
This manual page was generated by the Netpbm tool ’makeman’ from HTML source. The master documentation is at