SANE 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. 

WWW: http://www.mostang.com/sane/