gamma4scanimage(1)       SANE Scanner Access Now Easy       gamma4scanimage(1)



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 is 1.0, if the value is
       larger than 1.0 then the image gets 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 has to be in the range [0..maxin],
       highlight has to be 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 bits gamma input then maxin has
       to be set to 255, for 10 bits 1023, for 12 bits 4095, for 14 bits
       16383. The default is 16383.  To find out what value maxin has to be
       call scanimage with a very large gamma table [0]0-[99999]255 then
       scanimage prints an error message with the needed size of the gamma
       table.

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

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


SEE ALSO
       scanimage(1)


AUTHOR
       Oliver Rauch


EMAIL-CONTACT
       Oliver.Rauch@Rauch-Domain.DE



                                  10 Jul 2008               gamma4scanimage(1)
