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Radar used to detect concealed weapons in public spaces


March 26, 2013

Professor Kamal Sarabandi's technique could be used to provide extra security in a range of applications

Professor Kamal Sarabandi's technique could be used to provide extra security in a range of applications

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An electrical engineering professor at the University of Michigan believes that a type of radar, part developed by the Department of Defense, has the potential to be used as a means of detecting concealed weapons. Originally intended for military use, it is possible that the millimeter-wave radar system could be used to detect weapons across distances as large as a football field.

Professor Kamal Sarabandi was watching the aftermath of the Newtown shooting in Connecticut when he was hit by the notion that his work for the military may have a use a little closer to home.

The technology that he developed is currently being used in a number of applications, including collision avoidance systems in cars and in military targeting systems. The radar itself isn't particularly unique, but Sarabandi's pairing of the tech with Doppler radar signal processing allows it to pick out an individual in a crowd using a technique called polarimetry.

Doppler radar has a range of applications from speed traps to predicting the weather, using the Doppler effect to measure the speed of a given object. Sarabandi used motion capture techniques to identify the reflected signals from the limbs and torso of a human walking, creating what he calls “the DNA of walking.”

A computer is programmed to recognize the pattern, searching for a particular glare on the subjects chest, such that a hidden metal object might create. The technology focuses on the pedestrian's chest as it's both a common place that people hide weapons and acts as a fairly smooth backdrop, making it easier to pick out anomalies.

The polarimetric radar used by the team works by sending out a signal at a particular polarization, and carefully analyzing the polarization of the signal that bounces back. An irregular metal object can change the polarization of the signal, allowing for the detection of concealed items.

Though the technology has not yet undergone any human testing, Sarabandi's team has carried out a simulation using a mannequin painted with a coat that reflects radar-like human skin. The mannequin was placed on a turntable in an anechoic chamber, a room designed to absorb all echoes and reflections.

The techniques could be used to scan large groups of people, with each subject taking less than a second to process. This would then allow security personnel to closely observe the individual in question or even take suspects aside for more comprehensive scans.

The technology has significant potential to provide extra security in a wide range of applications, and while not entirely infallible, is significantly faster and less intrusive than the use of metal detectors.

One point worth noting is that while the technology appears to provide a fairly accurate means of locating hidden metal objects, it might be less effective at spotting some of the 3D printed weapons that are becoming more and more of a security issue as the technology continues to develop.

However, though the 3D printing of firearms is becoming more of a hot topic, it's currently only possible to print certain parts of the weapon, so there’ll still be some metal in there for detection.

Check out the video below for more on Kamal Sarabandi's new detection technique.

Source: University of Michigan

About the Author
Chris Wood Chris specializes in mobile technology for Gizmag, but also likes to dabble in the latest gaming gadgets. He has a degree in Politics and Ancient History from the University of Exeter, and lives in Gloucestershire, UK. In his spare time you might find him playing music, following a variety of sports or binge watching Game of Thrones. All articles by Chris Wood

I hope they do extensive research on the health effects of this and post it openly for all to see. I don't know what is more annoying, the potential for these things to give us cancer or how the hippies and conspiracy theorists react to it.

Also fake studies can be seen from a mile away even when perfectly done. Though on the other hand no matter what pretty much all those hippies and conspiracy theorists will say it's fake.

Ben O'Brien

I think this could definately be a game changer as far detecting threats in public or even private area's before it happens.

But i really worry about how intrusive this will be, i can just picture security personal picking out people at public events or places and taking them away to be scanned, and only a fraction of the time that person having anything dangerous on them.

I know people on one side will say that catching that fraction makes it all worthwhile, and the other side will say its not. For me i think it depends entirely where and when its used.


As far as privacy goes, object recognition algorithms can be developed to automate the scanning of individuals.

Gary Richardson

The problem stays. Guns aren't the only objects made of metal. Some clothes or boots contain it, as well.

Though, the idea is awesome. The concept is simple and if it indeed takes seconds to analyse the data, there is a huge potential here.

Maxim Chanturiay

"still be some metal" ... unless it's ceramic.


Now if they can get rid of that pesky constitutional provision against illegal search!

Vince Miller

If this works, it would take away the last "reason" gun proponents keep harping at people: "Anyone could be a bad guy carrying a gun, thus I must be free to have one ...blah blah".

Picture this: Have these detectors at hidden locations, mobile units in trucks, under roadways or hidden behind a garden wall.

So now every bad guy can be pulled out and have his gun taken away. Good guys get to keep theirs: they are legal after all. The bad guys will start carrying radar detectors, making themselves even more visible by suddenly making u-turns at spots where they detect radar. Sweet!

So before you know it there will be zones that can safely be labeled "legal gun owners in here only", but: What if now the good guys are asked, too, to hand over their guns? After all, some public shootings were done with legal, registered guns carried by their rightful owners. And if there are no bad guys with guns, "good" guys (none of which has ever stopped any of these mass shootings, but let's ignore that a sec) don't need a gun any more, either.

A nightmare for the NRA: Truly gun-free zones. No more reason for having any guns, at all. Not even a blunderbuss.


Many modern firearms are not made of metal


and watch the glock walk thru whilst my 20 round 9mm baby desert eagle gets caught, me and the baby from IMI, 20 rounds into tactical popup target range in less than 30 seconds, all on perps, no innocents, ten events, no errors

Bill Bennett

How about Professor Kamal Sarabandi, his family and friends volunteering for a year long testing program with this thing giving them a dose of radiation at frequent intervals each and every day.

Is this going to be used to detect criminals and terrorists with hidden guns or the public going about their business with a gun to give them the self-defence they reasonably wish for.

How many people will die from cancers caused by the radiation this emits compared to people who dies as a result of gun crime?

Mop-up all the propaganda your like telling you the low levels of radiation are not harmful - that's your prerogative - but I do not want to live in a world where I am unknowingly exposed to this dangerous pollution.

David Tobin

I've thought some like this might be viable for quite a while now. Aside from cost and trained personnel there are other considerations: Health effects Effect on cellular and radio signals ( and detonators) Effect on hearing aids, pacemakers and other non-discretionary electronics Method for handling false-positives


A Glock is not metal, but the bullets are... unless they develope non-metallic ammo this may still be useful. Just use it to look for bullets.

John Hagen-Brenner

This will cause one hell of a lot of intrusion on those of us who legally carry concealed weapons, millions of us. We're the ones who could have prevented a lot of these massacres..easily. But we weren't permitted to carry in certain locations. As always, these "solutions" have many more repercussions on freedom and safety than their creators envision.

My bet is these things will cause a lot more problems than they solve. But it will keep the anti safety, anti freedom, anti gun people deliriously happy.


okay to the first comment post, I am a hippie type and believe technology is well under utilized. This is a cool thing. Imagine all schools having this for early warning system to a threat. If it is for the mass public safety at gatherings of the masses, how could that be bad. As far as tests...will it kill a fish, a rodent...who knows but I do believe in testing first.

Scott Kelley

First power levels are so low it can't penetrate the first layer of water holding cells which reflects the MW back to be detected.

So what is being seen is the skin's surface and things in front of the skin, metal or otherwise and almost everything does show up, will show up in varying shades of gray or colors. But mostly it'll see a bunch of naked people waiting, walking around.

Many posting here should ask instead of making such inaccurate statements as it just makes you look bad or worse.


Radar "hit" on a person, assumed pedestrian. Is it a firearm? Is it a titanium cased tablet or phone or its case, Altoids tin, mesh RFID wallet, well you get the idea. What next? Do you pull them aside and check(search)? What is your probable cause?


Must for airports alone & end the TSA groin grab games etc aside other sensors too & dogs. Mass produce this for airport use

Stephen Russell

What we need is a scanner that can't see human flesh or at least digitaly removes it in real time to preserve a persons privicy. I'm pretty sure I get bathed in radar energy every time I go through a traffic light, speed camera or automatic shop door (my car radar detector goes nuts in shopping centers)


For BeWalt and others: An FBI crime classification report from 2005 identifies an individual as a mass murderer if he kills four or more people in a single incident (not including himself), typically in a single location. http://www.motherjones.com/mojo/2012/08/what-is-a-mass-shooting So if someone cruises into a church parking lot, kills three people there, and is then taken out by someone with a concealed permit before he gets to the sactuary where 1,600 people are gathered, it is technically not a mass shooting. So unless someone has a time machine, it is impossilbe to prevent a "mass shooting" since it does not exist until it happens.

Bruce H. Anderson

easy peasey. Simply carry in uncommon locations.... inside attache case behind metal cased laptop. Large rectangular print will not be taken for handgun. How about ankle carry rig? Very hard to detect. Under the armpit? Same thing. Small shadow right where there should be air.... but small. How about IWB at hip? Same story. Ah, maybe try wearing a hat, perhaps a tin can "combat" style helmet, painted purple to spoof The Man, but lookie here, I've a nice loaded nine under my hat. Others have mentioned the extra hassle we lawfully carrying folks would endure. I'm not game for that. As it is now I go almost everywhere and no one has a second thought about it. Not even LEO. They simply do not know I am armed. Now, what happens when I am, am "stung" by this gadget, but am fully compliant with the laws> Or will the eventual end game be to simply disarm everyone? Yes, that's it.... they want NOBODY to have arms of rtheir own. Maybe this thing has some aplication, but history shows it will be deployed anywhere and everywhere, leading to millions of unjustified "stop and frisk" encounters. We're not ready for that game, and I hope we never wil be.

Nick Jesch

So what, if I'm carrying concealed and this thing scans me, I'm automatically a "suspect"? I could be taken aside and searched in a room just for exercising my right to carry?

Matt Towns

Better start hiding those flasks somewhere else L

Jim Read

If any comment should be made, it is one thing to look for a handgun in the lab, quite another to find one on a person from several hundred thousand makes, configurations angles and with the clutter caused by keys ,change and the ever present mobile phone the search would need comparisons to several million possible combinations all of which would be defeated if the bad guys wear holsters which absorb enough EM waves to drop the signal return(Carbon composites).


With the metal in my body. I will drive them nuts

Reagan Conservative
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