pamunlookup - inverse of pamlookup
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.
This program is part of
Netpbm(1).
pamunlookup is best described as the inverse of
pamlookup (without
-byplane). 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 number.
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
.
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 output index
image is the size of the lookup table.
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:
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:
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.
In addition to the options common to all programs based on libnetpbm (most
notably
-quiet, see
Common Options ),
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.
pamlookup(1),
ppmchange(1),
pnmcolormap(1),
pnm(1),
pam(1)
pamunlookup was new in Netpbm 10.72 (September 2015).
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