Alfa ISBN Scanner allows to scan ISBN barcodes on your paper books. It's an add-on app for desktop program Alfa Ebooks Manager (alfaebooks.com).

With Alfa ISBN Scanner you can quickly create a list of ISBNs and save it to your computer (via email, IM or any cloud file sharing service) in a file isbns.txt.

Then open Alfa Ebooks Manager (File -> Import -> CSV), select this file and add ISBN-13 field to the import-field list. Thus you can quickly add all your paper books to your e-Library. Duplicates will be removed automatically.

Then, select imported books and using the Web Update (Books -> Web Update) parse book covers and metadata from Google Books, Amazon or other book sites.