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0 pointsmytailorisrich6y ago0 comments

Your reply illustrates my comment that some people only see the worst or try to imagine only the worst.

If a facial recognition system is only linked to a database of wanted people then it won't be able to ID people not on that database. I.e. if it is no worse than a normal CCTV for everyone who is not wanted by the police.

Therefore, in principle there is no negative impacts in terms of privacy or liberty compared to existing CCTVs.

The only issue is technical: False positives (which I'm not sure the numbers would be 'enormous' at the moment). This is bound to improve over time and can be mitigated with the appropriate police procedures on how to respond to an alert by such a system.

> for a supposedly free society (of which the United Kingdom no longer is one)

Of course if that's your opinion we're not going to be able to have a discussion on the topic...

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6 comments · 3 top-level

tolien6y ago· 3 in thread

Your assumption that the system throws away everything but the images of flagged people and number plates, and expires even those after some period of time, flies completely in the face of reality (e.g. the New York State Police were keeping all their collected ANPR data indefinitely [0]). A number of US states are making legal provisions to restrict how long ANPR data is retained for [2] - are they just tech pessimists too?

> False positives (which I'm not sure the numbers would be 'enormous' at the moment)

A 98% false positive rate [1] seems quite enormous.

> The Metropolitan Police’s system has produced 104 alerts of which only two were later confirmed to be positive matches

In another deployment:

> overall only 234 alerts – fewer than 10 per cent – were correct matches.

At least in the UK you're not going to be stopped by a police officer with a gun drawn on the basis of a failed read [3].

0: https://arstechnica.com/tech-policy/2012/09/your-car-tracked...

1: https://www.independent.co.uk/news/uk/home-news/met-police-f...

2: https://arstechnica.com/tech-policy/2015/03/virginia-passes-...

3: https://arstechnica.com/tech-policy/2014/04/due-to-license-p...

itcrowd6y ago

In addition to false positives, the false negative rate must also be given. For example: if 100 "suspect cars" pass by, but only 5 are identified as suspect, then 95% of the suspects are still on the loose and the system is again much less effective.

tolien6y ago

This FOIA response [1] reckons that there was a test where the false-negative rate was 20%, but there's also this report [2] of a 30% false negative rate at the Notting Hill carnival. So to continue your example, out of 100 known wanted people walking past the system 20-30 got through without being flagged.

1: https://www.whatdotheyknow.com/cy/request/use_of_automated_f...

2: https://theconversation.com/why-regulating-facial-recognitio...

mytailorisrichOP6y ago

You're not contradicting my points, you are giving anecdotal examples of problems and bad implementations. The only assumption I made is that we can have such systems implemented in a way that is properly controlled and harmless.

heavenlyblue6y ago

>> If a facial recognition system is only linked to a database of wanted people then it won't be able to ID people not on that database. I.e. if it is no worse than a normal CCTV

Yes, and it would still be able to match other possible suspects purely because they are on the wanted list.

Moreover, you are matching against _actual_ people meaning that whenever the system makes a mistake you are still arresting someone who isn’t wanted.

kevin_thibedeau6y ago

Faces aren't unique enough and innocent doppelgangers will eventually be abused.

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