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. matteason · 1790690246 · focus · HN ↗
    BTP say [0] that "the images and biometric data of those who don’t cause an alert are automatically and immediately deleted." - if that's true, they shouldn't be able to tell that it's the same faces being scanned multiple times so it has to be 500k total scans rather than, say, 500k unique faces across 2 million scans
    [0] <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...
    techjamie · 1790706077 · focus · HN ↗
    They're being very specific about images and biometric data, and they're weaseling those words for a reason. If they deleted all data about such scans, they'd say that.
    To do the lookup they're still hitting a database somewhere to know you aren't a concern, which is prime time to log that you were seen, when, and where. Then your "images and biometric data" can be "immediately deleted" since they've gotten anything else they want now.
    This is just a theory, but I bet I'm not far off.

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