Notes

Install order

1. gettext

2. libusb

3. sane-backends

4. Twain Sane Interface

Run

scaneimage -L

If not found, add to /usr/local/etc/sane.d/canon_dr.conf:

option vendor-name  CANON
option model-name   DR-C125
option version-name XXXX
usb 0x1083 0x1640

Now scaneimage -L returns something like:

device `canon_dr:libusb:003:011-1083-1640-00-00' is a CANON DR-C125 scanner

/Library/Image Capture