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 -byplane).  For example, the following
       normally yields output identical to 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.

   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 ), 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)