PDA

View Full Version : Face recognition software is a flop


DMB
05 Apr 2009, 10:40 AM
http://business.timesonline.co.uk/tol/business/industry_sectors/transport/article6036353.ece

AIRPORT face scanners designed to stop terrorists getting into the UK have been “rigged” to cut passenger queues and are creating an “unacceptable” security risk, a confidential Whitehall e-mail has claimed.

...Because of the growing number of “false negatives”, immigration officers say they were ordered last month to recalibrate the machines, lowering the match threshold from 80% to 30%.

...Using facial recognition software employed at Sydney airport in Australia, he found that even people of strikingly different appearance, such as Kevin Spacey and Winona Ryder, the Hollywood stars, showed a match of well above 30% with Osama Bin Laden. Gordon Brown was assessed as bearing even more similarity to Mel Gibson, the actor.

I like the idea that it couldn't tell Winona Ryder from Osama bin Laden.

It would, of course, be ridiculous to expect 100% accuracy. I wonder what the operational rules were for this system. After all, they also have human beings manning it. If the system throws up a resemblance, why can't they just do a visual check?

My knee replacement sounds the metal detector alarm every time I go through. So I always get a body search. This must happen to many other people. The body search is done by a human being. I don't think ti is going to be very efficient to try to remove the human element, fallible though it may be, from security checks.

Lugubert
05 Apr 2009, 02:48 PM
That's sufficiently close to what might be named The Great Lie Detector Hoax (http://www.guardian.co.uk/news/datablog/2009/mar/19/dwp-voice-risk-analysis-statistics).

Label shamelessly borrowed from G. Pullum: The Great Eskimo Vocabulary Hoax and Other Irreverent Essays on the Study of Language.

epepke
05 Apr 2009, 06:03 PM
I kept telling people this a long time ago.

premjan
05 Apr 2009, 10:07 PM
Why were they trying to do a 100% automatic match?

DMB
06 Apr 2009, 08:38 AM
Why were they trying to do a 100% automatic match?

Because they're not very bright?

farhat
06 Apr 2009, 10:23 AM
Why were they trying to do a 100% automatic match?

Oftentimes companies which sell such software will promise a lot more than they can deliver which leads to buyers thinking such software is infallible. A friend of mine used to work in a defense funded company in US which made this kind of software with the aim of picking out suspicious individuals by doing gait analysis. The problem, of course, was huge numbers of false positives.

epepke
06 Apr 2009, 01:55 PM
One problem is that people don't understand statistics. Bayes' theorem, y'all. You could have software that looks incredibly good on paper, but considering that there are so many non-terrorists versus terrorists, you're just going to get a lot of false positives. When you get a lot of false positives, the people assigned to check them out are going to get blase.

DMB
06 Apr 2009, 03:16 PM
Well, my knee generates false positives. It doesn't stop them searching me. I think there is always a problem with a human/software interface like this. The people operating it need to understand that it's a tool to help them, not something to replace their brains. In the case of face recognition it should be no more than the equivalent of having an extra colleague on the job -- one that doesn't get cross or tired.

I suspect that the people training them and the management who put it in place really don't understand the first thing about it.