Shelf reading made easy

Augumented Reality App for Shelf Reading

Another bit of technology for libraryland?  The AR shelf reading app can scan an entire shelf of books at one time and alert workers which ones are out of place.
This reminds of the days when we had to attach barcode labels to each book in the library collection when we became "automated."  With the Shelvar system, one would need to add a special tag (sort of like a QR code) to the spine of each book.  The QR-type tag represents the call number of the book.
This is a great way to check shelves and do inventory, but what happens with thin books?  Where do you put the tag?  Will the reader read around the spine edges?
I've never used RFID, but isn't this similar?