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[I focus only on the performance of facial recognition system, not on whether it's good idea to have such systems in place.] From the systems performance point

by mic47 8y ago

[I focus only on the performance of facial recognition system, not on whether it's good idea to have such systems in place.] From the systems performance point of view, this is non-story. If you deploy detection system, you have to make trade-off between precision (how many false positives you will have) and recall (how many false negatives -- misses) you will have [1]. How you do this trade-off depends on cost of false positive, and cost of false negative. For example, if false positive means, that someone will point camera to that part of stadium and someone will manually check if it's correct [2], and then arrest, then 2000 false positives might be good performance if recall is good, because there is no negative impact on false positive, only some wasted effort by police. On the other hand, if this AI match would be used as evidence in court, then the it would be terrible, as it would cause much more harm than good. From the article it seems that police is using it more closely to the first case, than to the second case, so the performance of this system might be good, so really the article is non-story. [1] I simplified the "precision" and "recall". [2] Or send more security guards / police to that area, or whatever discrete measure.

Retric 8y ago
People being arrested clearly qualifies as a negative impact. Asking for ID and arresting even 1 of those 2000 people also qualifys as a negative. Worse even if police simply go up to these people to do a manual comparison that's a downside as police confrontations risk death.
- mic47 8y ago
  Article does not claim happening any one of those, as there is no information about how police handle this. [edit] actually they claim that no false positive was arrested. But not others.
  - dpwm 8y ago
    Article in fact claims police force said no-one was arrested after an incorrect match. > It also said no-one had been arrested after an incorrect match.
- dpwm 8y ago
  I was going to state that I had read from a differently biased news source that nobody had been arrested, but the telegraph hasn't really reported it any differently to any other news outlet and contains this: > It also said no-one had been arrested after an incorrect match. Perhaps the real story here is that a system correctly identified 173 correct matches and that the police force clearly double-checked. That almost seems like an appropriate use of the technology. Now, there is highly likely to be a desire to improve the precision. I think this may be where the problems arise. Let's say the system only had false-positive rate of 10%. An officer arresting people based on the information is likely going to become complacent and assume that the system is much more likely to be correct than wrong. It gets worse the better the false-positive rate gets. Where my deep concerns are with such systems is that there is going to be a very strong temptation for the providers of such technology to store the false positives -- by definition not the people you thought they were and who will unlikely have given their consent -- in order to improve the precision and therefore their product. As there is effectively a wholesale opt-out of the GDPR for activities of the state at the cost of passing yet another ill-conceived law (to provide a lawful purpose or legal requirement) then there is no real reason why this won't be done. Such behaviour will lead to companies which effectively become privatised portions of the state with no viable competition -- their data is their secret that keeps them the only viable choice, and when they have precision at 95% and as a competitor you can only dream of having precision of 25%, then it seems somewhat unlikely that anybody would choose to use the other system at any price. As a competitor you will not have the lawful purpose unless working with a police force, which is unlikely with precision at 25%.
denzil_correa 8y ago
> From the article it seems that police is using it more closely to the first case, than to the second case, so the performance of this system might be good, so really the article is non-story I will quote Bruce Schneier on CCTV cameras > But the question really isn't whether cameras reduce crime; the question is whether they're worth it. And given their cost (£500 m in the past 10 years), their limited effectiveness, the potential for abuse (spying on naked women in their own homes, sharing nude images, selling best-of videos, and even spying on national politicians) and their Orwellian effects on privacy and civil liberties, most of the time they're not. The funds spent on CCTV cameras would be far better spent on hiring experienced police officers. https://www.schneier.com/essays/archives/2008/06/cctv_doesnt_keep_us.html https://www.schneier.com/essays/archives/2008/06/cctv_doesnt... Just replace CCTV cameras with AI.
joewee 8y ago
“because there is no negative impact on false positive, only some wasted effort by police.” This is incorrect. You don’t need to be “arrested” to be detained on a false positive hit, and being detained can ruin lives, missed work, missed family obligations, social stigma of having been a suspect. Also these systems do not have a way to correct false positives, so it’s likely to reoccur to the same individual multiple times which will have a real psychological impact. These systems have also shown to have higher false positive rate when looking at minority’s this creates a risk of further creating a cognitive bias among police. Don’t forget being detained as a suspect could result in you being added to a list you can’t remove yourself from.
- mic47 8y ago
  That was under condition "if false positive means, that someone will point camera to that part of stadium and someone will manually check if it's correct [2]". That means that false positive does not know that it's false positive.

by mic47 8y ago

Retric 8y ago

People being arrested clearly qualifies as a negative impact. Asking for ID and arresting even 1 of those 2000 people also qualifys as a negative. Worse even if police simply go up to these people to do a manual comparison that's a downside as police confrontations risk death.

mic47 8y ago
Article does not claim happening any one of those, as there is no information about how police handle this. [edit] actually they claim that no false positive was arrested. But not others.
- dpwm 8y ago
  Article in fact claims police force said no-one was arrested after an incorrect match. > It also said no-one had been arrested after an incorrect match.
dpwm 8y ago
I was going to state that I had read from a differently biased news source that nobody had been arrested, but the telegraph hasn't really reported it any differently to any other news outlet and contains this: > It also said no-one had been arrested after an incorrect match. Perhaps the real story here is that a system correctly identified 173 correct matches and that the police force clearly double-checked. That almost seems like an appropriate use of the technology. Now, there is highly likely to be a desire to improve the precision. I think this may be where the problems arise. Let's say the system only had false-positive rate of 10%. An officer arresting people based on the information is likely going to become complacent and assume that the system is much more likely to be correct than wrong. It gets worse the better the false-positive rate gets. Where my deep concerns are with such systems is that there is going to be a very strong temptation for the providers of such technology to store the false positives -- by definition not the people you thought they were and who will unlikely have given their consent -- in order to improve the precision and therefore their product. As there is effectively a wholesale opt-out of the GDPR for activities of the state at the cost of passing yet another ill-conceived law (to provide a lawful purpose or legal requirement) then there is no real reason why this won't be done. Such behaviour will lead to companies which effectively become privatised portions of the state with no viable competition -- their data is their secret that keeps them the only viable choice, and when they have precision at 95% and as a competitor you can only dream of having precision of 25%, then it seems somewhat unlikely that anybody would choose to use the other system at any price. As a competitor you will not have the lawful purpose unless working with a police force, which is unlikely with precision at 25%.

denzil_correa 8y ago

> From the article it seems that police is using it more closely to the first case, than to the second case, so the performance of this system might be good, so really the article is non-story I will quote Bruce Schneier on CCTV cameras > But the question really isn't whether cameras reduce crime; the question is whether they're worth it. And given their cost (£500 m in the past 10 years), their limited effectiveness, the potential for abuse (spying on naked women in their own homes, sharing nude images, selling best-of videos, and even spying on national politicians) and their Orwellian effects on privacy and civil liberties, most of the time they're not. The funds spent on CCTV cameras would be far better spent on hiring experienced police officers. https://www.schneier.com/essays/archives/2008/06/cctv_doesnt_keep_us.html https://www.schneier.com/essays/archives/2008/06/cctv_doesnt... Just replace CCTV cameras with AI.

joewee 8y ago

“because there is no negative impact on false positive, only some wasted effort by police.” This is incorrect. You don’t need to be “arrested” to be detained on a false positive hit, and being detained can ruin lives, missed work, missed family obligations, social stigma of having been a suspect. Also these systems do not have a way to correct false positives, so it’s likely to reoccur to the same individual multiple times which will have a real psychological impact. These systems have also shown to have higher false positive rate when looking at minority’s this creates a risk of further creating a cognitive bias among police. Don’t forget being detained as a suspect could result in you being added to a list you can’t remove yourself from.

mic47 8y ago
That was under condition "if false positive means, that someone will point camera to that part of stadium and someone will manually check if it's correct [2]". That means that false positive does not know that it's false positive.