How can I tell what songs are on my iPod that are not in my iTunes library?

My iPod contains 2710 songs, however my iTunes library has 2619 songs, I recently backed up my iTunes library on my new computer. How can I know what songs are on my iPod but aren't in my library?

Additionally, some songs do not have the title, instead they are capital letters such as "JLSD" I don't know how the song info got erased can someone please tell me how to fix this?