NAME

       gamma4scanimage - create a gamma table for scanimage

SYNOPSIS

       gamma4scanimage gamma [shadow [highlight [maxin [maxout]]]]

DESCRIPTION

       The  tool  gamma4scanimage  creates  a  gamma table in the format expected by scanimage. You can define a
       gamma, a shadow and a highlight value. You also can specify the size (maxin)  and  maximum  output  value
       (maxout) of the gamma table.

       gamma  is a floating point value, neutral value being 1.0. If the value is larger than 1.0 then the image
       is brighter.

       shadow defines the minimum input value that is necessary to create an  output  value  larger  than  zero.
       shadow has to be in the range [0..maxin].  Its default value is 0.

       highlight  defines  the maximum input value that produces an output value smaller than maxout.  highlight
       must be in the range [0..maxin] and larger than shadow. Its default value is the same as maxin (16383  if
       not set).

       maxin  defines the size of the gamma table. The size depends on the scanner/backend.  If the scanner uses
       8 bit gamma input then maxin must be set to 255, 1023 for 10 bits, 4095 for 12 bits,  and  16383  for  14
       bits.  The default is 16383.  To find out what value maxin has to be, call scanimage(1) with a very large
       gamma table [0]0-[99999]255 and scanimage(1) will print an error message  with  the  needed  gamma  table
       size.

       maxout  defines  the  maximum  output  value.  Take a look at the output of scanimage -h to find out what
       maxout must be. The default value is 255.

EXAMPLE

       scanimage --custom-gamma=yes --gamma-table `gamma4scanimage 1.8 0 11500 16383 255` >image.pnm

SEE ALSO

       sane(7), scanimage(1)

AUTHOR

       Oliver Rauch

EMAIL-CONTACT

       Oliver.Rauch@Rauch-Domain.DE

                                                   10 Jul 2008                                gamma4scanimage(1)