Facial recognition - tech question


BBC News - King's Cross developer defends use of facial recognition

Concerning (to me)
And can assure the forum that I don't intend anything dodgy.

But out of interest, would cycling glasses, dark, yellow or clear lenses frustrate these snoops?
Make sure you have a bicycle with you - this will render you invisible.

The serious answer is I don't know, but you'd thought that some forms of glasses would impede the system - dunno.
Good morning,

I suspect that as this is such new technology only the developers of each system will be able to tell you the exact impact.

It would also be wrong to do as I have just done and said "new technology", there isn't one way to do facial recognition, there are so many ways that the effects of hiding parts of face will vary.

I would suspect that in most systems there would be some sort of pre-processing of the image area believed to be a face to "move" the face to a standard orientation, so a face twisted to the side would be altered to one looking straight ahead.

If the glasses can be identified at this stage then the side of the head can be extrapolated from the face above and below the glasses, you can then guess where the eyes start and end. The weirder your face the more wrong the guess will be, so less accurate the match but by how much I have no idea.

So my suspicion would be that big weird shaped glasses would a hindrance but not much whereas clear ones would be insignificant, after all a huge number of people where glasses.

As the characteristics of eye obscuring glasses are nothing like skin recognising and replacing them with a guessed facial is probably easyish now and will only get better.

However this is all speculation.

The level of accuracy in the match and the consequences of getting it wrong will also affect the result, if you are tracking a shopper to see which shops he goes in you may be happy with a 75% certainty in the match. If you are going to use the information to ground a plane at an airport because you have found a match to a suspected terrorists 75% wouldn't be good enough.

So it seems likely that the Kings Cross cameras would track you and a few people who look like you as you. By wearing these glasses you may be flagged as someone visiting a shop or location that you didn't whereas a bare face would not have you flagged.

In other words there are consequences of trying to be invisible, the database may say there was a 60% chance that you entered the flat of "Luptuous Lil" and another mismatch of you visiting a bar whose clientele have tastes that are different from yours. By the time this information has been sold on/stolen and aggregated and the percentage match figures discarded as the the marketers don' understand them don't be surprised to get marketing material for things that are not of interest to you.

I would also suspect that the more that you obscure your face, the more likely it is that the images would be flagged for operator intervention. This could allow for multiple version of your face, some with and some without concealment to become part of the database, depending upon how important you are.


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Ride It Like You Stole It!
South Manchester
Get a bike, as said before, no-one sees you. I'm not worried, why should I be. Google and Apple track you better than face recognition ! It's scary


Toll Collector on the Road to Nowhere
The big issue with facial recognition is not whether Mr Average White Man is going to be identified, but the differential effects between people with different skin colour. Black people are basically far more likely to be misidentified (whether it's a false positive or false negative) than white people, for example.


Having said that, yes of course there are way of fooling face recognition, from special glasses that project infrared light, particular hair style or face paint (see for example Adam Harvey's CV Dazzle project: https://ahprojects.com/cvdazzle/) masks, hats, all kinds of things. Of course one of the main reasons than governments and malls have tried to ban masks, hoodies and hats (in some places) is precisely because of the rise of video surveillance.

But I wouldn't rely on technical failures or inaccuracies to protect you. The history of surveillance shows that failure is merely the stimulus to new and expanded forms of surveillance not rolling back surveillance, and failure in the context of the criminal justice system can actually be far more dangerous that success.

Personally, I would argue that facial recognition is public places is a step way too far (I've been arguing as much for almost 20 years). Its chilling effects on public social life and its built-in discrimination make it way too dangerous a technology. Law enforcement and government will just have to make do without out. We should be a society driven by state security concerns - that is a police state. And the private sector don't escape either - more and more of our apparently public space is actually pseudo-public (privately owned or operated) and what the private sector does is more and more significant. It's also not 'fun' (as some bad and club owners have tried to make out. That's almost the worst thing here - oppressive technology presented as some kind of a game. Gamification is something we really need to be careful of.
Blue Hills
Get a bike, as said before, no-one sees you. I'm not worried, why should I be. Google and Apple track you better than face recognition ! It's scary
Well yes - am typing this and the original post on a chromebook :smile:
Was just interested - and don't like the idea anyway.
I can see that clear glasses won't disrupt it but would have thought dark biggish cycling glasses would, unless they are matching me to other shots of me similarly bedecked as I wander round London.
some interesting replies - thanks


There are several countermeasures people have devised to play with the FR algorithm, a bit like navy dazzle camouflage it puts things where they shouldn't be. You may have to keep updating your countermeasures.


Charming but somewhat feckless
That this is being used by a private company is worrying. What database are they comparing their facial recognition results against?


That this is being used by a private company is worrying. What database are they comparing their facial recognition results against?
There is no indication that it is hooked up to a database of likely characters. More probable would be a system that can track a face in real time across the cctv network. This does not need a database. Not sure how much this breaks any data protection law.
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