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)