Thread

500k facial scans at UK stations yield no arrests, 1 false positive

518 points · 305 comments · ilamont

blitzar · 1790684008 · focus · HN ↗
16 deployments for 6 months at rail stations - they must have been off 99% of the time to only scan 500k faces.
For scale 500k people is 2 days of Liverpool Street Stations daily average
1. mrweasel · 1790684677 · focus · HN ↗
  A lot of those are going to be the same people day in and day out, the article says 500k faces, not people. You also have to filter out those people where the cameras aren't getting an image good enough to scan.
  The article doesn't say, and I haven't seen the cameras, but it's not like you're getting every single person parsing through those stations.
  But, yes, the numbers seems low.
  1. blitzar · 1790721563 · focus · HN ↗
    Digging in it cameras were deployed 21 times for about 4 hours each time ... matching against a watchlist of around 400 faces.
    Sounds like it was intended to achieve the outcome it achieved - a near zero false positive rate. If I were a betting person, I would wager the threshold for a match was set comically high.
    <a href="https://www.btp.police.uk/police-forces/british-transport-police/areas/about-us/about-us/facial-recognition-technology/" rel="nofollow">https://www.btp.police.uk/police-forces/british-transport-po...

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