SANE ("Scanner Access Now Easy") is a universal scanner interface.
The value of such a universal interface is that it allows writing
just one driver per image acquisition device rather than one driver
for each device and application. So, if you have three applications
and four devices, traditionally you'd have had to write 12 different
programs.  With SANE, this number is reduced to seven: the three
applications plus the four drivers. Of course, the savings get even
bigger as more and more drivers and/or applications are added.

sane-backends contains documentation, several backends, scanimage
command line frontend, and networking support. For other/graphical
frontends take a look at sane-frontends and/or xsane.

WWW: http://www.sane-project.org/