From XPUB & Lens-Based wiki

Install scanimage on Debian:

$ sudo apt install sane-utils

Then you can use it:

$ scanimage

Check if your device is recognized:

$ scanimage -L

To see what options you have for the specific device:

$ scanimage --help -d 'fujitsu:ScanSnap S1500:2314'

Now you can scan, and configure the scanner as you like:

$ scanimage -d 'fujitsu:ScanSnap S1500:2314' --resolution 300 --mode gray

You can also skip the "-d" option, then scanimage will select the default scanner.

$ scanimage --resolution 300 --mode gray