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Engineers Say They've Created Way To Detect Weapons Using Wi-Fi (gizmodo.com)
An anonymous reader quotes a report from Gizmodo: The researchers, which include engineers from Rutgers University-New Brunswick, Indiana University-Purdue University Indianapolis (IUPUI), and Binghamton University, published a study this month detailing a method in which common wifi can be used to easily and efficiently identify weapons, bombs, and explosive chemicals in public spaces that don't typically have affordable screening options. The researchers' system uses channel state information (CSI) from run-of-the-mill wifi. It can first identify whether there are dangerous objects in baggage without having to physically rifle through it. It then determines what the material is and what the risk level is. The researchers tested the detection system using 15 different objects across three categories -- metal, liquid, and non-dangerous -- as well as with six bags and boxes across three categories -- backpack or handbag, cardboard box, and a thick plastic bag.
The findings were pretty impressive. According to the researchers, their system is 99 percent accurate when it comes to identifying dangerous and non-dangerous objects. It is 97 percent accurate when determining whether the dangerous object is metal or liquid, the study says. When it comes to detecting suspicious objects in various bags, the system was over 95 percent accurate. The researchers state in the paper that their detection system only needs a wifi device with two to three antennas, and can run on existing networks.
The findings were pretty impressive. According to the researchers, their system is 99 percent accurate when it comes to identifying dangerous and non-dangerous objects. It is 97 percent accurate when determining whether the dangerous object is metal or liquid, the study says. When it comes to detecting suspicious objects in various bags, the system was over 95 percent accurate. The researchers state in the paper that their detection system only needs a wifi device with two to three antennas, and can run on existing networks.
They forgot I think to think about the trivial countermeasures, like lining the suitcases with aluminum foil, or using aluminum suitcases, or putting absorbent ferrite sheets in instead. You can't see what doesn't reflect or reflects all or absorbs a lot.
This is absolutely horrific. You are telling me that these idiots who've gone along with the NSA illegally monitoring our traffic can now use state backdoors to identify every bit of gold/silver/gun wealth and resistance across the country? Wifi is everywhere and *I* can get into half the systems using nothing but default credentials.
I'll stick with my trusty ADE 651, thankyouverymuch!
the preceding comment is my own and in no way reflects the opinion of the Joint Chiefs of Staff
This is using 2.4GHz microwaves to scan for certain types of objects (large metal objects, nitrogen-containing explosives). Basically a more advanced metal detector.
Unfortunately, from reading the paper, it seems like they've failed to measure the real effectiveness of their system -- they only measured the false negative rate and used just that for their "effectiveness". They never even bothered to check for or measure false positives. With such useless measures its easy to get a 100% effective system -- simply categorize everything as dangerous. Then your false negattive rate is 0% and your "effectiveness" is 100%.
Time to fire the TSA! ;)
Anons need not reply. Questions end with a question mark.
Even 99% accurate is absolutely horrid for real-life situations. Let's take a case where one in a thousand items encountered are dangerous. I'm going to scale the numbers to make the results come out as integers. At 1 in 1000, if we start with 100,000 items we'll have 100 dangerous items and 99,900 non-dangerous. Of the dangerous items, the system will flag 99 as dangerous and 1 as non-dangerous. Of the non-dangerous items, the system will flag 98,901 as non-dangerous and 999 as dangerous. So out of 1,098 items flaged as dangerous, 90.98% of them will be non-dangerous. So a system that claims a 99% accuracy rate will have a 91% error rate when it comes to sounding the "Danger!" alarm. Only 9% of the time will that alarm actually indicate danger, the other 91% of the time it's a false alarm.
The above is why 5-nines (99.999% accuracy) is the baseline for workable systems.
That's why I always put my iRifle on airplane mode when I don't want to be detected.
"That's the way to do it" - Punch
strange
Signal reflectivity and object characterization is fairly evolved. 1-5% error is pretty clever, but it stands to get more testing, as the madness of what people bring in terms of metallic contraband is huge.
Might it mistake a flask of booze rather than suntan lotion? I'm not sure. Could a big hunk of metal be mistaken for a pistol? Again, not sure. They have to prove effectiveness, or the litigation potential could make many lawyers really rich.
Before a commercial deployment, I'm betting there are guidelines as regards the reality of what's possible. Until then, it's only speculation that it has inexpensive commercial potential-- and every pricey competitor will fight it-- for their loss of profits.
---- Teach Peace. It's Cheaper Than War.
It can't hurt to ask.
---- The above post was generated by the Turing Institute. Maybe.
They forgot I think to think about the trivial countermeasures
Not really because these have trivial solutions: just flag any bag which shows a huge amount of reflection or none at all as suspicious. Then, instead of a quick automated scan, you can be detained by security and wait while they rummage through your bag.
Positive Molecular Locator is well-known device which works exactly in the same way. https://en.wikipedia.org/wiki/...
I imagine if you were to do a cost comparison, it would compare rather well.
This likely isn't meant as a replacement for x-ray inspection machines, but could be a good solution for public venues such as concerts, stadiums, schools, etc.
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This was an interesting experiment done by some students. It's not some amazing new idea that is going to revolutionize security. First off, they only tested it by putting the object directly between the transmitter and the receiver. And like 10m apart. So, basically like every other type of scanner around. You're still going to have to walk through it. So while that might make it easier to implement a scanner type device, it's not like suddenly anywhere with WIFI can start scanning all the people around it at will.
Unfortunately, the reporting is lacking in highlighting this. I suspect, frankly, because those reporting on it don't really understand what they're looking at.
The method of detection in this case is rather crude. In reality, no fancy countermeasures are necessary. Take your contraband item and simply enclose it in the shape of something harmless, and this system would be immediately fooled.
In tomography, you shoot a known signal through a target at a certain location and direction. Then based on how the signal is altered at your receiver, you back out what it could've gone through to cause that alteration. Do this at enough locations and directions, and you can build up a picture of what's in between. Basically how a CAT scan works (Computer Aided Tomography - shoots x-rays through the body in different directions).
There's nothing particularly new about tomography. It's been known about and used for decades (though it didn't really take off until computers could do the grunt work of crunching the numbers). What's new here is that they're using WiFi signals (microwaves) instead of x-rays, and their transmitter and receiver are just a regular WiFi router and access card. I suppose it shouldn't be surprising that such commercial grade equipment has enough sensitivity to be used this way. If you take the sensitivity of a modern cellular phone radio (typically transmits at 100-250 mW) and convert it to the visual spectrum, it's roughly equivalent to (assuming no line of sight issues) standing in Washington D.C. and being able tell if a candle (about 1 Watt of light) has been lit in Philadelphia 140 miles away.
... because it will be monetized.
"Psst ... wanna buy newer underwear?"
It little behooves the best of us to comment on the rest of us.
Mold crushed up aluminium foil in the shape of a gun and put it in your carry on bag, watch the expression on the face of the xray operator!
I wonder if is able to distinguish between a metal laptop case filled with explosive and a real laptop. If it does not, then it is of little help.
It FIRST detects if something is dangerous, with 99% accuracy, and THEN detects if it is metal or liquid? Don't you all see that this is mumbo jumbo? It makes no sense at all.
The article is missing some vital information, making it look like it works excellent. BUT it really doesn't, it only works with 0,5 meter range and only detected the stuff correctly if it was in a specific position... Wake me up when it works in a range of 3-5 meter (a normal passage way in a subway/airport/whatever) and detects it correctly in any position. Also wonder how it works if one would line the inside of a bag with aluminiumsheets (or even some copper wiring)