Results: 62 books on those four shelves, 55 of which were recognised. On three of the shelves, the first and last books have been missed, with the second to last book also missed on the second shelf, and on the fourth shelf a book in the middle has been missed. However, as everything else has been recognised correctly, even if the photo was rubbish, I'm leaning more towards me not taking the photo properly (which makes sense for the first and last books being cut out).
Having recognised 55, it tells me I can claim five, one of which is a repeat. Claiming them, however, is proving difficult, as the app is either not recognising the cover, or is recognising it as a different book...
The app also insists on keeping your flash on when taking a photo, and when it's trying to recognise a cover for a claim, which can take up to five minutes. Not good for the battery life.
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But yeah, it's a nice idea. And I agree that digital copies should be freely available if you have a physical copy.