simplistic grayscale assignment for machine generated, color images
see also :
ppmtopgm - ppmhist
add an example, a script, a trick and tips
no example yet ...
... Feel free to add your own example above to help other Linux-lovers !
portable pixmap as input, performs a simplistic grayscale
assignment intended for use with grayscale or bitmap
conversion from ppm to pgm will yield an image with contrast
too low for good printer output. The program maximizes
contrast between the gray levels output.
A ppm input of
n colors is read, and a pgm of n gray levels is written. The
gray levels take on the values 0..n-1, while maxval takes on
from color to stepped grayscale can be performed in order of
input pixel intensity, or input pixel frequency (number of
Sort input colors by the number
of times a color appears in the input, before mapping to
evenly distributed graylevels of output. -intensity
Sort input colors by their grayscale intensity, before
mapping to evenly distributed graylevels of output. This is
for images with a very small number of colors. Perhaps
should have been an option to ppmtopgm(1).
ppmhist , ppm
1993 by Dan Stromberg.