11 Body Parts Researchers Will Use to Track You

Cell phones that can identify you by how you walk. Fingerprint scanners that work from 25 feet away. Radars that pick up your heartbeat from behind concrete walls. Algorithms that can tell identical twins apart. Eyebrows and earlobes that give you away. A new generation of technologies is emerging that can identify you by your physiology. And unlike the old crop of biometric systems, you don't need to be right up close to the scanner in order to be identified. If they work as advertised, they may be able to identify you without you ever knowing you've been spotted.

Biometrics had a boom after 9/11. Gobs of government money poured into face and iris recognition systems; the Pentagon alone spent nearly $3 billion in five years, and the Defense Department was only one of many federal agencies funneling cash in the technologies. Civil libertarians feared the worst as face-spotters were turned on crowds of citizens in the hopes of catching a single crook.

But while the technologies proved helpful in verifying identities at entry points from Iraq to international airports, the hype -- or panic -- surrounding biometrics never quite panned out. Even after all that investment, scanners still aren't particularly good at finding a particular face in the crowd, for example; variable lighting conditions and angles (not to mention hats) continue to confound the systems.

Eventually, the biometrics market -- and the government enthusiasm for it -- cooled off. The technological development has not. Corporate and academic labs are continuing to find new ways to ID people with more accuracy, and from further away. Here are 11 projects.

The Ear

My, what noticeable ears you have. So noticeable in fact that researchers are exploring ways to detect the ears' features like they were fingerprints. In 2010, a group of British researchers used a process called "image ray transform" to shoot light rays at human ears, and then repeat an algorithm to draw an image of the tubular-shaped parts of the organ. The curved edges around the rim of the ear is a characteristic -- and most obvious -- example. Then, the researchers converted the images into a series of numbers marking the image as your own. Finally, it's just a matter of a machine scanning your ears again, and matching it up to what's already stored in the system, which the researchers were able to do accurately 99.6 percent of the time. In March of 2012, a pair of New Delhi scientists also tried scanning ears using Gabor filters -- a kind of digital image processor similar to human vision -- but were accurate to a mere 92 to 96.9 percent, according to a recent survey (pdf) of ear biometric research.

It may even be possible to develop ear-scanning in a way that makes it more reliable than fingerprints. The reason is because your fingerprints can callous over when doing a lot of hard work. But ears, by and large, don't change much over the course of a lifespan. There's a debate around this, however, and fingerprinting has a much longer and established history behind it. A big question is whether ear-scanning will work given different amounts of light, or when covered (even partially) by hair or jewelry. But if ear-scanners get to the point of being practical, then they could possibly work alongside fingerprinting instead of replacing them. Maybe in the future we'll see more extreme ear modificationcome along as a counter-measure.


In the early and mid-2000s, the Pentagon's blue-sky researchers at Darpa dabbled in something called the "Unique Signature Detection Project," which sought to explore ways to detect people by their scent, and maybe even spot and identify individuals based on their distinct smells. Darpa's work ended in 2008. The following year, the Department of Homeland Security fielded a solicitation for research in ways that human scent can indicate whether someone "might be engaging in deception," specifically at airports and other ports of entry.

Odor detection is still just a research project at the moment. The science is intricate, involving more than 300 chemical compounds that produce human odor. Our personal stinks can change depending on everything from what we eat to our environment. But it may be possible to distinguish our "primary odor" -- separate from "secondary" odors based on our diet and "tertiary" odors based on things like soaps and shampoos. The primary odor is the one linked to our genetics, and there have already been experiments with mice, which have been found to produce distinct scents unique to individuals. In 2007, the government's counter-terror Technical Support Working Group even started a program aimed atcollecting and storing human odors for the military's dog handlers. Dogs, of course, have been used to track people by smell for decades, and are believed to distinguish between humans based on our genetic markers.


Your chest moves, just a little, every time your heart beats or your lungs take in air. For years, researchers have been monkeying with radars that are sensitive enough to to detect those minuscule chest movements -- but powerful enough to do it from hundreds of yards away. Even reinforced concrete walls and electromagnetic shielding won't stop these radars, or so claim the researchers at the small, Arizona-based defense contractor VAWD Engineering, who are working on such a system for Darpa's "Biometrics-at-a-distance" program.

The key is the Doppler Effect -- the changes in frequency when one object moves relative to another. We hear it all the time, when a fire engine passes by, siren blaring. VAWD says their vehicle-mounted Sense Through Obstruction Remote Monitoring System (STORMS) can pick up even small fluctuations of chests.

STORM "can be used to detect, classify and identify the specific cardiac and pulmonary modulations of a... person of interest," a company document boasts. By itself, a heartbeat or a breathing rate won't serve as a definitive biometric. But combine it with soft biometrics (how someone subtly sways when he or she stands) and you've got a unique signature for that person that can't be hidden or covered up.

VAWD says these signature will help improve disaster relief and medical care by providing a "reliable, real time medical status equal to or better than the current devices, while increasing the mobility and comfort of the patient."

But the company also notes that its system performs "automated human life-form target tracking" even when construction materials like "Afghan mud-huts" are in the way. STORM "has already been deployed by the United States Army on one of its most advanced ground vehicles," the company adds.

Does any of that sound like hospital work to you?


Most people are likely to be familiar with voice readers on gadgets like the iPhone. But what if there was software that could quickly analyze the voice of thousands, and even use those voices to identify specific people?

Russian biometrics firm Speech Technology Center -- known as SpeechPro in the U.S. -- has the technology. Called VoiceGrid, the system is able to automatically recognize a person's voice as their own, provided your voice is pre-recorded in a database and can be recalled by the computer. The company has also developed a version for "large city, county, state or national system deployments."

It's seen use in Mexico, according to Slate, "where it is being used by law enforcement to collect, store, and search hundreds of thousands of voice-prints." The National Security Agency has taken interest in similar technology. So has the FBI. A 2012 presentation from the National Institute of Standards and Technology -- with the assistance of the FBI -- also speculated on potential uses including identifying and clearing people 'involved in illegal activities," locating serial killers and identifying arms traffickers(.pdf). Iarpa, the intelligence community's research agency, has also been looking into ways to solve some of its problems: audio interference mainly. In 2011, the agency concluded its Biometric Exploitation Science and Technology Program (or BEST), which made "speaker recognition advances which included improving robustness to noise, reverberation, and vocal effort, and by automatically detecting these conditions in audio channels," spokesperson Schira Madan told Danger Room in an email. But we wonder if it'll detect autotune.

The Iris

Imagine a scanner than can look deep inside your eye -- from 10 feet away. Actually, you don't have to think that hard. The technology is already here. Scanners have been developed that can focus in and scan irises from a distance of 10 feet, such the IOM PassPort, developed by government contractor SRI International. The company promises the machine can scan irises at a rate of 30 people per minute -- like in high-traffic areas such as airports and train stations. SRI also claims it can see through contact lenses and glasses.

But the longer-range scanners could also see other uses, aside from airports. U.S. troops field existing, short-range and handheld iris scanners to build databases of Afghan eyes as part of a plan to use biometric data to tell civilians apart from insurgents. The Department of Homeland Security has tested iris scanners at a Border Patrol station along the Texas-Mexico border. The FBI has been working on an iris database for federal prisoners, and Google uses them at company data centers. But these systems can be fussy, and require that the targets don't move too much.

There might be another way. The Pentagon's scientists at Darpa have funded a research project at Southern Methodist University to develop cameras that can automatically zoom-in and scan irises, kinda like what happened to Tom Cruise in Minority Report -- and without being blocked by pesky obstructions like eyelashes and glare from light. But another problem is that iris scanners are not the most secure means of identifying people. In July 2012, a group of researchers from the U.S. and Spain discovered a way to spoof the scanners by duplicating iris images stored in databases and creating synthetic copies. That means someone could conceivably steal your eyes, in a way.


Spotting someone by their irises is one of the best-developed biometric techniques there is. But Savvides and his Carnegie Mellon colleagues think there may be an equally-promising approach in the area around the eye -- also known as the "periocular" region.

The "periocular region has the most dense and the most complex biomedical features on human face, e.g. contour, eyelids, eyeball, eyebrow, etc., which could all vary in shape, size and color," they wrote in a 2011 paper. (.pdf) "Biologically and genetically speaking, a more complex structure means more 'coding processing' going on with fetal development, and therefore more proteins and genes involved in the determination of appearance. That is why the periocular region should be the most important facial area for distinguishing people."

And unlike other biometrics -- the face, for instance -- the periocular region stays remarkably stable as a person ages. "The shape and location of eyes remain largely unchanged while the mouth, nose, chin, cheek, etc., are more susceptible to changes given a loosened skin," the researchers note. In other words, this is a marker for life.

Nearby, Savvides and his colleagues think they've found a second biometric: the shape of the eyebrow. Face-scanners are sometimes thrown off when people smile or frown. But the eyebrow shape is "particularly resilient to certain (but not all) expression variations," the researchers note in a separate, yet-to-be-published paper. And the eyebrow can still be seen, even when the subject has most of his or her face covered.

What's not fully clear is how the eyebrow biometric responds to threading, shaving or waxing. Saavides, who responded to tons of questions about his research, says there's no fullproof means to avoid this kind of spoofing. But Saavides is also working on sensors that can analyze multiple facial cues and features, while incorporating algorithms that detect the possibility of a person changing one or two of them. A pair of plucked eyebrows might be a weak match compared to the bushy ones the computer has on file -- but the computer could also be smart enough to recognize they've been plucked.

Long-Range Fingerprint Scanners

Most fingerprint scanners today require physical contact, but constantly being soaked with finger-oil and dirt can also muck-up the machines. For that reason, among others, one developer is working on a scanner that may one day read your fingerprints at a distance of 20 feet.

But first, scanners with a 20-foot distance haven't hit the market quite yet. One machine called the AIRprint, made by Alabama firm Advanced Optical Systems, has a range of nine feet, and uses two 1.3 megapixel cameras that receives light in different wavelengths: one horizontally polarized, and the other vertically polarized. To sort out the different wavelengths, a device beams light at your fingerprints, which bounce back into the lenses, which then combines the separate wavelengths into a clear picture. A spin-off company called IDair also has a commercial scanner that reaches up to six feet and is marketed toward "security personnel." IDair's 20-foot-range machine is currently in development, and is described as functioning similar to satellite imagery.

The military is reportedly an interested customer. The MIT Technology Review surmised that Marines may use them for scanning fingerprints from inside the relative safety of an armored vehicle or behind a blast wall. It beats exposing yourself to the possibility of a suicide bomb attack. For the civilian market, that seems better than pressing your fingertips against a greasy scanner, if you're comfortable with the idea of having your prints scanned from far away.


Even before 9/11, researchers were floating that notion that you could pick out someone by how he or she walks. And after the Towers fell, Darpa made gait recognition one of the cornerstones of its infamous Total Information Awareness counterterror program.

The problem is that gait can be kind of hard to spot. A briefcase or a bum leg prevents the recognition system from getting a clear view. So filming someone walk didn't make for a particularly reliable biometric system. Plus, the same person may have multiple gaits -- one for walking, and another for running, say.

But the spread of smartphones has opened up a new way of identifying someone's stride. Androids and iPhones all have accelerometers -- sensors that measure how far, how fast, and with how much force an object moves.

"By using the accelerometer sensor in the cell phone, we are able to capture a person's walking pattern. As it turns out, these patterns are very good biometric traits for people identification. Because it does not require any special devices, the gait biometrics of a subject can even be captured without him or her knowing," write Carnegie Mellon University professor Marios Savvides and his colleagues in a recent paper. (.pdf)

In a small, preliminary study, Savvides and his fellow researchers at the CyLab Biometrics Center claim they were able to get a 99.4% verification rate with the system when the subjects were walking. 61% of the time, they were even able to match someone's fast-paced gait to their slower one. In other words, you can run.... but with a phone in your pocket, it's going to be harder to hide.


The Army wants to see some sweat. No, not workout sweat, but sweat that can betray hostile intentions. In 2010, the Army awarded a nearly $70,000 contract to California security firm Irvine Sensors Corporation to develop software that can use sensors to recognize at "abnormal perspiration and changes in body temperature." The idea was to determine "harmful intent in such military applications as border patrol, stand-off interrogation, surveillance and commercial applications" including surveillance at businesses and "shopping areas." It's a bit out there, and still very much in the research stage, but makes a certain kind of sense. Elevated stress levels could give a suspect away when scanned by hyperspectral sensors that read changes in body temperature.

Though a reliable system will have to work in combination with other biometric signals: threatening body movements, facial expressions, iris scans -- all of these will also have to be factored into determining whether someone is up to no good. The Army contract, dubbed Image Analysis for Personal Intent, also sought to develop sensors that read these signs from a distance of nearly 150 feet. Perhaps a bit optimistic. But in 2002, a group of scientists in Minnesota managed to determine if military recruits were engaging in deception by scanning for changes in temperature around their eyes. So if you're at all freaked out about the idea of sweat-scanners, now might be time for a cold shower.

Advanced Face Recognition

Most machines that scan and recognize your face require taking a good, clean look. But now researchers are working on replacing them with scanners that only need a few fragmentary snapshots at much longer ranges than ever before.

One machine that can do it is being developed by defense contractor Progeny Systems Corporation, called the "Long Range, Non-cooperative, Biometric Tagging, Tracking and Location" system. Once a person of interest is spotted, the system captures a 2D image of the person's face before converting it into 3D. Then, once the image has been converted and filed in a database, it can be quickly recalled when the system spots the person for a second time. That's because 3D reduces the number of pixels needed to analyze the image, speeding up the process and allowing the system to identify a person with a mere glance. The company also claims the machine works at more than 750 feet.

But a face alone may not be enough to recognize a person with a machine. Everything from lighting conditions to distance can make it harder to get a clear picture, especially if the person being scanned is on the move, in a crowd, or ducking in and out of buildings. Using 3D models makes it easier, but the technology will likely have to be combined with "soft biometrics" like an individual's gender, height, weight, skin color and even tattoos.

Slightly creepy, no? Well, it gets creepier, like the group of Swiss scientists working on scanning facial features to detect your emotions. Developers at Carnegie Mellon University have also developed a mobile app called PittPatt --which has since been acquired by Google -- that can scan your face and match it up with images you've shared over the internet, all in less than a minute.

Rapid DNA Testing

It used to be that DNA testing took months to perform, from the time when a DNA sample was picked up on a swab, to analyzing it and creating a DNA profile. Now there are machines that can do it in less than 90 minutes, and the Pentagon wants them.

This month, researchers at the University of North Texas are beginning to test a $250,000 machine for the Defense and Justice Departments, and the Department of Homeland Security, so that "casualties and enemies killed in action can be quickly identified in the field," according to the Biometrics Research Group. But according to the October issue of Special Operations Technology magazine, rapid DNA testing systems co-developed by defense giant Northrop Grumman had already been delivered to "unspecified government customers" beginning back in August. One of those customers is believed to be the FBI. California company IntegenX also has a portable rapid-DNA machine that can analyze molecules taken off everything from clothing to cigarette butts. There's a simple reason why police are so interested. For a burglar who's breaking nto houses and leaving a DNA trail, the machines could clue-in faster than the burglar is able to continue the spree.