Face-Scanning Loses by a Nose in Palm Beach

Rio writes: "A story from myCFnow.com reports that Palm Beach International Airport officials said face-scanning technology will not become part of their airport's security system." Looks like the ACLU was right. Checking a database of 15 employees, the technology gave false-negatives -- failed to recognize the test subjects -- over 50% of the time. A spokesperson said, "There's room for improvement." The Pentagon said the same thing in February. The false-positive rate is more important -- it isn't mentioned, but even if it were just 0.1%, Bruce Schneier argues, it'd be useless.

Comments

That explains alot...

[chriso11]

Perhaps this is why I can't remember anyone's name - half the people look the same

Try telling the Aussies that.

[serps]

Airport face identification isn't practical? Try telling the Australian Government that. They are trialling a hybrid face-recognition/biometric passport system that sends shivers up my spine.

what does this do

[vectus]

but delay its deployment for a couple years? this isn't really a victory at all.. I mean, I bet this will only delay the technology two years.. maybe less.

If anything, it should be a call for all Americans to protest this kind of thing (should you disagree with it).

Re:only 15 employees?

[Triskaidekaphobia]

If it is a small sample then a high false negative rate is even worse.

If it can't identify 1 of 15, then what chance has it got of finding 1 person out of millions?

Unpopular View

[deebaine]

I don't necessarily understand the objections to face scanning technology. To be sure, I don't want computers flagging people to be arrested. But computers sift through enormous amounts of information, making them ideal for a first pass. If they are used to flag people to be scrutinized by humans, I don't have any objections. In fact, if a computer can flag 20 of the hundreds of thousands of faces so that human experts can give a closer look, so much the better.

Incidentally, by this reasoning, it is in fact the false negatives that are more important. False positives can presumably be discarded by humans providing closer scrutiny. False negatives in this scenario, however, present a major difficulty.

Face scanning technology isn't innately evil. Like everything else, if we use it wisely, it can help. If we use it irresponsibly, it can hurt. No surprises there.

-db

Re:Unpopular View

[achurch]

I don't necessarily understand the objections to face scanning technology. [...] Like everything else, if we use it wisely, it can help. If we use it irresponsibly, it can hurt.

You just hit the nail on the head there; most people who don't like this technology don't like it because (they believe) it will be used irresponsibly, eventually if not immediately. Power corrupts, as the old saying goes, and people are unfortunately easily corruptible. Ordinarily I wouldn't be quite so pessimistic, but given all the hoopla over the "War on Terrorism", I'm inclined to side with the Slashdot popular view.

(Note to moderators: Yes, I do realize that there are many points of view represented on Slashdot, thankyouverymuch.)

Re:Unpopular View

[TheCage]

But what about the fact that it doesn't solve the problem? This is presumably to stop terrorism, yet a significant number of terrorists are not part of any database, which is required for something like this to work. Seems just like a waste of money to me.

False positives, fales negatives, and wasting time

[markwelch]

The notion that someone will repeatedly be "identified" as matching a particular face, is a very real concern for travelers. Already, we find that Americans with brown skin and beards, and especially persons who "look" Muslim, are hassled every time they enter an airport and often miss their flights. Non-citizens who "appear Muslim" should probably just give up on any idea of flying in the next few years.

As noted, there can be no "get past ID check free" letter or ID card, since those would immediately be forged. And with a 50% false negative rate (missing a suspect 50% of the time), the system seems hardly worth using.

I have not traveled by air since returning from Europe on September 19 (delayed from Sept. 12).

In the past, I would have flown between the San Francisco Bay Area and the Los Angeles area (a 1-hour flight, using any of the airports on either end), but now it's actually likely to be faster to drive (around six hours each way), after including all the "waiting in line time," the increased flight delays, and of course the time to get into and out of the airports (park here, rent a car there).

To be fair, of course, a system with a 50% false negative rate is presumably able to detect "known suspects" 50% of the time, which is almost certainly much better than human beings will ever do. Of course, the tests are probably being conducted under very favorable conditions, with an extremely small sample of "suspects." And of course, if the false-positives were equally distributed, we'd all be willing to suffer a one-in-a-thousand delay, if it actually had any meaningful benefit. (But we know that the false-positives won't be equally distributed, they will mostly affect persons in certain ethnic groups or with beards, etc., and while that means I'm less likely to be inconvenienced, I can't tolerate a system that punishes people for their skin color or ethnic background.)

What's scary, to me, is that we are giving up so much (in many little bits and pieces) for so little benefit. On Saturday, I discovered that I couldn't use the restrooms in the BART (train) stations again, because they were closed to prevent someone from planting a bomb in them. Okay, so I had to hold it for an hour until I got home, big deal. And armed troops in the airports, and on bridges, okay, I can live with that one thing. And I can't drop off my express mail without handing it to a postal clerk now.

But ding, ding, ding, we add up all the little "show-off" gimmicks and what we face is a huge impact that provides pretty much zero actual benefit. All the gimmicks combined might provide about 1% or 10% improved safety, at a much greater cost.

While I was stuck in London during the week after September 11, I worried that things would change for the worse, not because of things that terrorists did, but because of the things we would do out of panic and fear and prejudice and idiocy. Things are nowhere near my worst fears, but I think things are very bad, and ultimately I believe that the terrorists have already "won" by causing most Americans to change multiple aspects of our "way of life."

Re:False Positives are OK

[Phroggy]

Actually, true story: I was at Fred Meyer's a few weeks ago (for those not fortunate enough to live in the Northwest, they sell pretty much everything, at decent quality and decent prices). In addition to my groceries, I'd picked up a pair of khaki pants. They've now got those self-checkout scanner things, in addition to the regular checkout lines, so I decided I'd try it. I didn't do so well. Anyway, in particular, I hadn't noticed that the pants had a security tag on them, and I neglected to remove it. I'm not sure how I would have removed it anyway, but the really large man keeping an eye on the self-checkout lines would surely have taken care of it.

So I cram the pants and half my groceries into my backpack, the other half in plastic bags. I leave. The alarm goes off. It occurs to me that the pants must have a security tag that I didn't remove. I glance around, and nobody even looks my direction. I proceed to leave the building.

Then I remember that I've forgotten to buy a bus pass. I go back in. The alarm goes off. I head over to the customer service counter, and shell out $56 for a little card that will enable me to get to/from work for the next month. I leave again, and the alarm goes off. I wait a few minutes for the bus, and go home.

I completely forget about the security tag until I'm wearing the pants and am on my way to catch the bus to work. I've gotten about a block when I hear a noise as I'm walking. Sure enough, there it is. I run home, try unsuccessfully to get it off, give up, change pants, and run to catch the bus. I arrive at work 15 minutes late. When I get home I finish mutilating the tag. Tough little buggers.

So anyway, the moral of the story is that those little tags are absolutely worthless if store security is asleep at the wheel.

Look-alikes?

[TheSHAD0W]

Here's one for you: What would you do if you looked like a terrorist?

Let's say, some time in the future, they get the face-scanning technology to work right. 0.000001% false-positive rate. And it's implemented all over the US.

Let's also say that, among the 250 million people in the United States, one or more people had facial structures similar enough to terrorists' that they would trigger those scanners. In fact, they'd trigger every scanner that person was surveiled by. And let's say that person were you.

What would you do?

You couldn't go to an airport. You couldn't go to a major public attraction. You probably couldn't go to a public place without fear of some alarm going off and people waving automatic weapons in your face. Would you cower at home? Would you wear a bag over your head? Would you sue the US government? How would you cope?

False positives

[Restil]

We're not talking about using this technology to make courtroom identifications. We're using it to notify security that you MIGHT have someone in front of you that is of less than reputable character. This doesn't mean you immediately cuff him and throw him in jail, but if he tries to walk through a screener checkpoint it MIGHT be a good idea to do a little better check than a simple wand wave. In the meantime, someone can be checking the pictures to see if that person's face actually matches the match the computer made. With a .1% false positive rate, you could have a couple paid employees just looking at matching pictures to see if there's really cause for concern or not. At the rate people go through screening checkpoints now, they'll get a "match" about once every 10 minutes or so, your mileage may vary with larger airports, its all a matter of scale.

As for false negatives, even 50% is better than nothing as long as the false positive is much MUCH lower. Imagine catching 50% of the hijackers on September 11 before they boarded the planes. A lot of red flags could have gone up, and flights could have been delayed, the rest of the passengers could be more carefully scrutinized. No, this is not the solution to any problem. And no, it should not be used legally any more than a lie detector can be. Its a guide. It tells us where we might need to concentrate more of our efforts on.

As far as threats to privacy go, this makes sense in an airport, but it does not make sense out on the street. People go into an airport expecting to be searched, questioned, carded, etc. They do not have the same expectation while walking down the street. So unless the cops are currently chasing someone, they lose him, and you have a striking resemblance, they shouldn't bother you at all.

-Restil

No, it's 99.99% Read Cryptogram

[AftanGustur]

Bruce talks about 99.9%, so there's 0.1% left, not 0.01% as the story says right now.

No, sorry, just read Bruce's Cryptogram

Suppose this magically effective face-recognition software is 99.99 percent accurate. That is, if someone is a terrorist, there is a 99.99 percent chance that the software indicates "terrorist," and if someone is not a terrorist, there is a 99.99 percent chance that the software indicates "non-terrorist." Assume that one in ten million flyers, on average, is a terrorist. Is the software any good?

No. The software will generate 1000 false alarms for every one real terrorist. And every false alarm still means that all the security people go through all of their security procedures. Because the population of non-terrorists is so much larger than the number of terrorists, the test is useless. This result is counterintuitive and surprising, but it is correct. The false alarms in this kind of system render it mostly useless. It's "The Boy Who Cried Wolf" increased 1000-fold.