Apple told us they had improved Touch ID fingerprint recognition in iOS 7.1.1, but they didn’t both to tell us how they did it. Now, a Redditor shares how he says Apple pulls off the feat of making Touch ID not only more accurate, but faster.
Apparently, the reason that accuracy would decay over time was down to users screwing up their first scans, when the auto-correction feature needed a perfect start to work properly going forward.
This is the relevant part of Redditor iOSecure’s post. The first part describes how Touch ID works. The second paragraph goes into the changes Apple made in iOS 7.1.1.
Touch ID takes a 88×88 500ppi scan of your finger and temporarily sends that data to a secure cache located near the RAM, after the data is vectorized and forwarded to the secure enclave located on the top left of the A7 near the M7 processor it is immediately discarded after processing. The fingerprint scanner uses subdermal [sic] ridge flows (inner layer of skin) to prevent loss of accuracy if you were to have micro cuts or debris on your finger.
With iOS 7.1.1 Apple now takes multiple scans of each position you place finger at setup instead of a single one and uses algorithms to predict potential errors that could arise in the future. Touch ID was supposed to gradually improve accuracy with every scan but the problem was if you didn’t scan well on setup it would ruin your experience until you re-setup your finger. iOS 7.1.1 not only removes that problem and increases accuracy but also greatly reduces the calculations your iPhone 5S had to make while unlocking the device which means you should get a much faster unlock time.
While we’re not experts on Touch ID and how Apple does it here at MacTrast, tis certainly seems reasonable enough. Although – and this is just anecdotal evidence – it seems as if my iPhone 5s takes a slight bit more time to unlock via Touch ID following the iOS 7.1.1 update.
Have you noticed an improvement in the way Touch ID works for you? Did you have to re-scan your fingerprints to see an improvement? Please, share your experiences with us in the comments section below.
(Also, thanks to Bruce Schneier)