Installing brscan4 for my brother scanner doesn't work on a fresh Ubuntu 16.10 install
I did a ldd /usr/lib64/sane/libsane-brother4.so and I've got:
libusb-0.1.so.4 => not found
So I guessed I would need to install this dependency.
To install it, just run: sudo apt-get install libusb-0.1-4
And voilà:
$ scanimage -L
device `brother4:net1;dev0' is a Brother DCP7070DW DCP-7070DW