Posts Tagged ‘laser’

by David Hambling

Everyone’s heart is different. Like the iris or fingerprint, our unique cardiac signature can be used as a way to tell us apart. Crucially, it can be done from a distance.

It’s that last point that has intrigued US Special Forces. Other long-range biometric techniques include gait analysis, which identifies someone by the way he or she walks. This method was supposedly used to identify an infamous ISIS terrorist before a drone strike. But gaits, like faces, are not necessarily distinctive. An individual’s cardiac signature is unique, though, and unlike faces or gait, it remains constant and cannot be altered or disguised.

Long-range detection
A new device, developed for the Pentagon after US Special Forces requested it, can identify people without seeing their face: instead it detects their unique cardiac signature with an infrared laser. While it works at 200 meters (219 yards), longer distances could be possible with a better laser. “I don’t want to say you could do it from space,” says Steward Remaly, of the Pentagon’s Combatting Terrorism Technical Support Office, “but longer ranges should be possible.”

Contact infrared sensors are often used to automatically record a patient’s pulse. They work by detecting the changes in reflection of infrared light caused by blood flow. By contrast, the new device, called Jetson, uses a technique known as laser vibrometry to detect the surface movement caused by the heartbeat. This works though typical clothing like a shirt and a jacket (though not thicker clothing such as a winter coat).

The most common way of carrying out remote biometric identification is by face recognition. But this needs good, frontal view of the face, which can be hard to obtain, especially from a drone. Face recognition may also be confused by beards, sunglasses, or headscarves.

Cardiac signatures are already used for security identification. The Canadian company Nymi has developed a wrist-worn pulse sensor as an alternative to fingerprint identification. The technology has been trialed by the Halifax building society in the UK.

Jetson extends this approach by adapting an off-the shelf device that is usually used to check vibration from a distance in structures such as wind turbines. For Jetson, a special gimbal was added so that an invisible, quarter-size laser spot could be kept on a target. It takes about 30 seconds to get a good return, so at present the device is only effective where the subject is sitting or standing.

Better than face recognition
Remaly’s team then developed algorithms capable of extracting a cardiac signature from the laser signals. He claims that Jetson can achieve over 95% accuracy under good conditions, and this might be further improved. In practice, it’s likely that Jetson would be used alongside facial recognition or other identification methods.

Wenyao Xu of the State University of New York at Buffalo has also developed a remote cardiac sensor, although it works only up to 20 meters away and uses radar. He believes the cardiac approach is far more robust than facial recognition. “Compared with face, cardiac biometrics are more stable and can reach more than 98% accuracy,” he says.

One glaring limitation is the need for a database of cardiac signatures, but even without this the system has its uses. For example, an insurgent seen in a group planting an IED could later be positively identified from a cardiac signature, even if the person’s name and face are unknown. Biometric data is also routinely collected by US armed forces in Iraq and Afghanistan, so cardiac data could be added to that library.

In the longer run, this technology could find many more uses, its developers believe. For example, a doctor could scan for arrythmias and other conditions remotely, or hospitals could monitor the condition of patients without having to wire them up to machines.

https://www.technologyreview.com/s/613891/the-pentagon-has-a-laser-that-can-identify-people-from-a-distanceby-their-heartbeat/

A laser weapon made by Lockheed Martin can stop a small truck dead in its tracks from more than a mile (1.6 kilometers) away, the company announced this week.

The laser system, called ATHENA (short for Advanced Test High Energy Asset), is designed to protect military forces and key infrastructure, Lockheed Martin representatives said. During a recent field test, the laser managed to burn through and disable a small truck’s engine.

The truck was not driving normally; it was on a platform with the engine and drivetrain running, Lockheed Martin representatives said. The milestone is the highest power ever documented by a laser weapon of its type, according to the company. Lockheed is expected to conduct additional tests of ATHENA.

“Fiber-optic lasers are revolutionizing directed energy systems,” Keoki Jackson, Lockheed Martin’s chief technology officer, said in a statement. “This test represents the next step to providing lightweight and rugged laser-weapon systems for military aircraft, helicopters, ships and trucks.”

The ATHENA system could be a boon for the military because the laser can stop ground-based adversaries from interfering with operations long before they reach the front lines, company representatives said.

The laser weapon is based on a similar system called Area Defense Anti-Munitions (also developed by Lockheed Martin), which focuses on airborne threats. The 30-kilowatt Accelerated Laser Demonstration Initiative — the laser in ATHENA itself — was also made by Lockheed.

The recent test was the first time that such a laser was tested in the field, the company said. The Accelerated Laser Demonstration Initiative is a multifiber laser created through a technique called spectral beam combining. Essentially, the system takes multiple lasers and mashes them into one. Lockheed representatives said this beam “provides greater efficiency and lethality than multiple individual 10-kilowatt lasers used in other systems.”

Last year, Lockheed also highlighted laser defense capabilities in a demonstration test between two boats that were located about 1 mile apart. The vessels, described as “military-grade,” were stopped less than 30 seconds after the laser burned through the boat’s rubber hull.

http://www.livescience.com/50064-laser-weapon-stops-truck.html

Thanks to Da Brayn for bringing this to the attention of the It’s Interesting community.

A new treatment has successfully changed the color of people’s eyes in Latin America, but the procedure isn’t approved in the U.S. yet.

For years, a California-based company called Stroma Medical has been publicizing a laser procedure that turns brown eyes blue. Theoretically, this would give brown-eyed individuals the choice to change the tint of their irises, not unlike the way many decide to use surgery to alter the noses or chests they were born with.

Now Stroma Medical claims that it has conducted 37 successful treatments on patients in Mexico and Costa Rica. It also says that it would likely charge about $5,000 for anyone wanting the procedure. That is, of course, only if and when American medical safety regulators give the surgery the green light in the United States.

Company chairman Gregg Homer says the procedure works by disturbing the thin layer of pigment that exists on the surfaces of all brown irises.

“The fundamental principle is that under every brown eye is a blue eye,” Homer told CNN. “If you take that pigment away, then the light can enter the stroma—the little fibers that look like bicycle spokes in a light eye—and when the light scatters it only reflects back the shortest wavelengths and that’s the blue end of the spectrum.”

Although the treatment lasts only 20 seconds, the patient’s eye color isn’t changed right away. Instead, it takes a few weeks for the human body to remove the pigmented tissue, resulting in blue eyes.

Given that light eyes are increasingly rare, with less than a fifth of Americans boasting blue peepers, it’s easy to see how there might be demand for this procedure. A preference for blue eyes in Western societies has been documented in many unscientific ways, though controlled studies suggest that the blue-eyes-are-more-attractive stereotype is more a product of culture than unconscious preference.

Whether or not you feel this procedure is a net good—or bad—thing for society, a bigger concern might be safety.

Though Stroma claims the surgery is safe, at least one ophthalmologist cautioned that the shedding of pigment could clog up drainage channels in the eye, increasing pressure and the risk for glaucoma.

http://time.com/money/3733372/surgery-turn-brown-eyes-blue/

Water often damages metals, causing rust, wear and decay.

Thanks to an innovative laser process, however, metal is getting its revenge.

University of Rochester scientists Chunlei Guo and Anatoliy Vorobyev have developed a technique using extremely precise laser patterns that renders metals superhydrophobic: in other words, incredibly water-repellent.

Imagine a much more powerful Teflon — except that Guo and Vorobyev’s material isn’t a coating but part of the metal itself. Water actually bounces off the surface and rolls away.

The possibilities are many, Guo says. Kitchenware, of course. Airplanes: No more worrying about de-icing, because water won’t be able to freeze on aircraft in the first place.

And sanitation in poor countries, an idea close to the heart of the Bill and Melinda Gates Foundation, which helped fund the project. Thanks to the surface’s repellent properties, it’s essentially self-cleaning.

Ironically, Guo was inspired by a project in which he and a team treated a variety of materials to make them superhydrophilic — that is, water-attracting.

“We worked with a variety of materials — not just metal but semiconductors, glass, other things,” he said. Even on a vertical surface, “the effect was very strong. If I drop a drop of water on the bottom of this surface, it would actually shoot up against gravity, uphill. So that really motivated us to look into this reverse process.”

In their paper, the two compared the surface to that of a lotus leaf, which has “a hierarchical structure containing a larger micro-scale structure” and is superhydrophobic.

“Our structure sort of mimics, in some way, this natural (arrangement) of the lotus leaf,” Guo said.

And like the lotus leaf, because the laser-patterned metal is so water-repellent, it has self-cleaning properties. In an experiment, Guo dumped some household dust from a vacuum cleaner on a treated surface. Just a few drops of water collected the dust, and the metal remained dry.

In their work, the scientists used platinum, titanium and brass as sample metals, but Guo says he believes it could work for a wide variety of metals — not to mention other substances.

The process is still very much of the lab. It took the scientists an hour to treat a 1-inch-by-1-inch sample and required extremely short bursts of the laser lasting a femtosecond, or a millionth of a billionth of a second.

But Guo is optimistic about ramping up the process for industrial use, and he says the goal for the sanitation project is to “really push the technology out” in the next two or three years.

And then?

“I do believe down the line we will be able to make it accessible to everyday life,” he said.

Watch out, water.

The scientists’ paper was published in the Journal of Applied Physics. The project was also funded by the U.S. Air Force Office of Scientific Research.

http://www.cnn.com/2015/01/22/us/feat-metal-repels-water-rochester/index.html