Can Imaging Technologies Save Us From Terrorists? 480
itwbennett writes "In the aftermath of the failed Christmas Day terrorist attack, full body scanning technologies such as millimeter wave and backscatter are regaining popularity, writes blogger Steven J. Vaughan-Nichols in a recent post. But, he asks, do they really work? The TSA seems to think so. It has just issued a contract to purchase more millimeter wave scanners from L3 Communications. Michael Chertoff, the former homeland security secretary, told the New York Times that if these scanners had been in place, they would have caught the would-be bomber. Ben Wallace, the Conservative Member of Parliament in the United Kingdom, disagrees, saying that the technologies can't detect the kind of low-density explosive that the would-be terrorist tried to use on December 25th."
On a related note. . . (Score:5, Informative)
New scanners break child porn laws [guardian.co.uk]
RTFA (Score:3, Informative)
Re:Just wait... (Score:5, Informative)
As soon as these scanners are deployed terrorists will simply start to carry the explosives in an internal cavity. 80g of explosives - the amount used on the 25th - only has a volume of 36x36x36 mm^3. There are plenty of places where this could be hidden - just look at the drug mules..
So you will still need to be searched, even if you are travelling in the nude. But at least the searches would take less time.
Re:... but not if (Score:2, Informative)
Re:... but not if (Score:4, Informative)
ITYM "unsuccessfully, killing only the bomber".
It's like jumping on your own hand grenade.
(Must of made a horrible mess though).
http://www.theregister.co.uk/2009/09/21/bum_bombing/ [theregister.co.uk]
Re:Just wait... (Score:1, Informative)
It doesn't matter if they work or not, so long as we spend lots of money purchasing them. Guns ROUTINELY make it past screening when the government's official testers try to get them past.
As to flying nude, you'd also need to require a colonoscopy and dental exam at the gate. Then, of course, you'd need to have equal vigilance on everyone who worked on the outside or inside of the plane, including the manufacturers.
Of course, even if all those were done, there is NO security for small planes. I've flown internationally on a 10 seater and had no security check whatsoever, because it was a small plane. Those planes can cause quite a bit of damage to larger planes, and so on. They will never have security, as many are corporate jets, flown by the guys who pay the largest amounts to political candidates.
Re:They are another layer (Score:3, Informative)
Hi, thanks for biting. Here [nationalgeographic.com] is a passive broadband millimeter-wave/terahertz (100-2000 GHz) image of a subject with two items beneath several layers of clothing. One is a metal gun, and you're right, a magnetometer would detect that easily.
The object on the left, however, is a very thin piece of foam. Its overall weight is much less than the 3 oz of PETN the underpants bomber had. It is thin for obvious reasons that I do not need to explain here.
By the way, low vapor pressure of explosives is a serious problem for those "puffer" machines, so imaging technologies are the only real way to detect them.
Re:RTFA (Score:5, Informative)
Radiation in general isn't the problem. There's some evidence that millimeter wave radiation in particular can un-zip DNA, even at its low energy, due to resonant effects.
http://www.technologyreview.com/blog/arxiv/24331/ [technologyreview.com]
Now it's not yet clear *how* damaging regular exposure to a millimeter wave scan would be -- millimeter waves already exist in the natural environment and haven't killed us all yet -- so it's entirely possible that there is no real danger. But I'd like to see some of the billions spent on these machines used to verify that before we get too far along.
Re:... but not if (Score:3, Informative)
The bomb was smallish. Thanks to the internet we know that an object the size of a grenade will fit with some work, and with a friction igniter (German potato masher and other grenades had these) iit could be detonated by a pull string.
Booty bomb:
http://www.stratfor.com/weekly/20090902_aqap_paradigm_shifts_and_lessons_learned [stratfor.com]
Classic pull fuse:
http://www.inert-ord.net/gerimp/eggs/41204.jpg [inert-ord.net]
Omit all metal, make a plastic case that looks like a convincing turd, and a considerable amount of ordnance could be carried.
Re:It should be noted that (Score:3, Informative)
Also, he's no longer Secretary of Homeland Security.
Re:... but not if (Score:2, Informative)
Re:They are another layer (Score:3, Informative)
The NG text, like all popular press reporting, has problems. The liquid-filled pouch being undetectable is false. Passive systems like the one in the NG article measure radiometric temperature, not physical temperature, so you need to consider both physical temperature and surface emissivity.
You correctly point out, like everyone else, that a single system cannot detect all threats. Hence the subject of my original post... layers. Pat-downs, lists of suspicious people, magnetometers, puffers. Nothing's perfect, but most of these individual systems already exist. The imaging systems are basically the final frontier, and probably the last system that is reasonable.
Cost is a big issue, yes. But there is the economy of scale, as well as other uses for these technologies. Did you know that the active millimeter-wave systems actually are used in high-end clothing retailers for extremely accurate body measurements [it-fits.info]? This is the exact same L-3 system used in US airports [dsxray.com]. Millimeter-wave radar/imaging is also used for aircraft landing systems. Research in these technologies helps everywhere, not just security in airports.
Re:Just wait... (Score:4, Informative)
I've read a newspaper article on just this - the controversy over installing better 3D imaging scanners to "catch more terrorists" (though that one was dealing specifically with Canada). There was an interesting take on the problem there offered by an Israeli airport security expert.
What he said was that, basically, extreme tech measures are still not good enough to battle the really creative terrorists, and, broadly speaking, only make things worse because they slow down processing, resulting in large numbers of people accumulating before security checkpoints. Which means that a would-be terrorist suicide bomber doesn't need to get to the plane anymore - if he detonates an explosive in the crowd, it's likely to have a very damaging effect already; and, since he didn't have to go through any screening yet, he can easily get a much more powerful explosive device that what he could otherwise smuggle on-board. In other words, instead of a theoretical minor increase in security and safety, we get a very real decrease!
He went on to explain that in Israel, they instead require all passengers to go through a brief interview (which, he claims, is faster with trained personnel than a proper - that is, actually able to thwart most attempts to conceal explosives - device scan), check the person's background file (collected beforehand), and look for certain cues (speech irregularities, facial expressions, and other similar signs) of instability when relevant topics are touched. He further claims that this has an extremely high detection rate for real threats, and a very marginal false positive rate, so a full scan using advanced imaging machinery has to be done on very few people in practice. In particular, from the description of the recent terrorist's behavior in the airport during departure, he is confident that the terrorist wouldn't have gotten past security in any Israeli airport.
Considering how Israelis generally have much more of a headache with terrorism, and their extremely good success rate at preventing it specifically on their airline and in their airports (there was precisely one successful hijacking of El Al airplane, for example), I would definitely trust them on this matter.
Re:Passive IR or Backscatter (Score:3, Informative)
It's not IR... IR cannot penetrate clothing, so it is not great for this application; here's the paper you want to read [aip.org]. As I said, the image in the NG article is in the approximately 100-2000 GHz range, and it's passive.
And yes, everyone is confused about the sensor modalities. There are three. 1) Active narrowband millimeter-wave. Basically imaging radar. 2) Passive broadband millimeter-wave/terahertz. 3) X-ray backscatter. (also active of course, but a stretch to be called radar)
Each one has advantages and disadvantages. The problem is that they all get lumped into the "body scanner" category in the popular press (since that is what they do), and then the advantages and disadvantages get completely mixed up. To answer your question, the TSA is currently using (1) and (3) in airports.
Regarding the "strip search" issue, it really seems to depend on the individual. Yes, the high-resolution systems essentially display you without clothing, but on the other hand, the images look nothing like what you would see with your eyes. It has been said that they could appear on the front cover of Time or Reader's Digest in grocery store checkout lanes, and they wouldn't get covered up like the cover of Cosmo usually does. That's just someone's opinion, of course. Everyone has them...
Re:They are another layer (Score:4, Informative)
Active systems, as they exist now, are portal only. Thus there is only the exposure to several seconds of either millimeter-wave or x-ray radiation while in the portal. Also, the operators have no control over the emitted power. It is constant, person to person. The SNR of active systems is incredible even at such low radiation levels; increasing it would do nothing useful.
Regarding your comment of crowd scanning; this is how some passive systems work, but (currently) no active systems. Passive, i.e., picture a CCD. Visible or IR currently, right? Well, imagine a millimeter-wave/terahertz one. Still passive, but can see through clothing at decreased spatial resolution (diffraction limited). No harm done by standing in front of a passive sensor all day long.
About the transmission/storage of images: That is determined by the final system manufacturer and the TSA. I work only on the imaging hardware and initial display. I tend to agree with you, however.
Why millimeter-wave over IR? IR cannot penetrate clothing as well as you think [aip.org]. And IR sensors are no more 'safe' than passive millimeter-wave/terahertz sensors: both are 100% safe.