gamma4scanimage(1) SANE Scanner Access Now Easygamma4scanimage(1)NAMEgamma4scanimage - create a gamma table for scanimage
SYNOPSISgamma4scanimage gamma [shadow [highlight [maxin [max-
out]]]]
DESCRIPTION
The tool gamma4scanimage creates a gamma table in the for-
mat 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 minmum 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 `gamma4scanim-
age 1.8 0 11500 16383 255` >image.pnm
SEE ALSOscanimage(7)AUTHOR
Oliver Rauch
EMAIL-CONTACT
Oliver.Rauch@Rauch-Domain.DE
sane-backends 1.0.12 11 Sep 2002 gamma4scanimage(1)