Pamunlookup User Manual(1) General Commands Manual Pamunlookup User Manual(1)
NAME
pamunlookup - inverse of pamlookup
SYNOPSIS
pamunlookup -lookupfile=lookupfile inputfile
All options can be abbreviated to their shortest unique prefix. You
may use two hyphens instead of one. You may separate an option name
and its value with white space instead of an equals sign.
DESCRIPTION
This program is part of Netpbm(1).
pamunlookup is best described as the inverse of pamlookup (without -by-
plane). For example, the following normally yields output identical
the input:
$ cat input.ppm | \
pamunlookup -lookupfile=map.pam | \
pamlookup -lookupfile=map.pam \
> output.ppm
Specifically, pamunlookup takes an input image and produces an output
image of the same width and height in which each tuple is a single num-
ber. That number is the index in a given lookup table of the tuple
value that is in the same position in the input image.
You specify the lookup table the same way as for pamlookup
⟨pamlookup.html#lookupimage⟩ .
Where a tuple in the input image is not in the lookup table, the number
pamunlookup places in the output index image is one greater than the
highest index in the lookup table. Accordingly, the maxval of the out-
put index image is the size of the lookup table.
Example
Here is an example of pamunlookup's function.
Consider an input image consisting of a 3x2 PPM as follows:
red yellow red
beige beige beige
and a lookup table consisting of a 3x1 PPM image as follows:
red yellow beige
The lookup table above says Index 0 corresponds to the color red, Index
1 corresponds to yellow, and Index 2 corresponds to beige. The output
of pamunlookup is the following index image:
0 1 0
2 2 2
Miscellaneous
The inputfile argument identifies the file containing the index PAM or
PNM image. - means Standard Input. It won't work if both the input
image file and lookup table file are Standard Input.
The output index image goes to Standard Output.
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), pamunlookup recognizes
the following command line option:
-lookupfile=lookupfile
lookupfile names the file that contains the PAM or PNM image
that is the lookup table. This option is mandatory.
SEE ALSO
pamlookup(1), ppmchange(1), pnmcolormap(1), pnm(1), pam(1)
HISTORY
pamunlookup was new in Netpbm 10.72 (September 2015).
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/pamunlookup.html
netpbm documentation 09 August 2015 Pamunlookup User Manual(1)
Generated by dwww version 1.15 on Sat Jun 29 02:11:09 CEST 2024.