Tracy Staedter

May 17th 2019

Infrared Technology Reveals the Unseen


Infrared technology, based on a wavelength of light invisible to human eyes, is being harnessed for dozens of astonishing uses. Just below the color red on the electromagnetic spectrum, this type of radiant energy was discovered by Sir William Herschel, an amateur astronomer famous for finding Uranus in 1781. During World War II, German scientists developed night-vision technology based on infrared light. Today, the military has adopted a wide range of uses for this scientific breakthrough, including infrared scanners, guidance heads for missiles, night vision goggles and missile defense systems, such as Northrop Grumman’s LAIRCM system, for aircraft. But infrared applications go beyond the battlefield to help improve life in unexpected ways. Here are just three.

Forecast Extreme Weather

Weather on Earth is intense and costly. A new report published in December 2018 by Christian Aid, a U.K.-based charity, found that the three most expensive weather disasters worldwide that year occurred in the United States. They were Hurricane Florence, which killed 53 people and caused $17 billion in damages; Hurricane Michael, which killed 43 people and cost $15 billion; and the Camp Fire in California, the state’s deadliest and most destructive in almost a century. It killed at least 85 people, wiped out the town of Paradise and destroyed about 14,000 homes, causing an estimated $7.5 to $10 billion worth of damage.

Predicting extreme weather depends heavily on satellites that orbit the Earth and track conditions in the oceans and atmosphere. Two new satellites — GOES-16 and GOES-17, launched in 2016 and 2018, respectively — are now online and working together to provide high-resolution visible and infrared imagery as well as lightning observations for improved forecasting. Part of the National Oceanic and Atmospheric Administration’s (NOAA) Joint Polar Satellite System, the sister spacecraft will draw upon a suite of sensors, some of which rely upon infrared technology to measure aerosols in the atmosphere, along with clouds, thunderstorms, hurricanes, rainfall, moisture, atmospheric motion and volcanic ash. They’ll also identify fire and hot spots, crucial to forecasters in the western United States. Data from the satellites will reveal atmospheric processes associated with thunderstorms and hurricanes, reports NOAA. It will also indicate cold clouds, which are associated with storms that produce tornadoes, hail and strong wind.

Catch Wildlife Poachers

Wildlife poaching has reached epic proportions. In 2018, 769 rhinos were killed illegally in South Africa for their horns, according to Save the Rhino. And about 100 elephants are killed every day in Africa for their ivory tusks, meat and body parts, reports World Elephant Day. Until recently, wildlife rangers equipped with military packs, weaponry and vehicles were no match for poachers, who typically prowl sanctuaries and savannahs at night by foot to make stealthy getaways.

But recently, the World Wildlife Federation started enlisting infrared and other technology to give gamekeepers an advantage. Handheld infrared cameras as well as those mounted on vehicles, stationary posts and even on drones help security personnel spot unwelcome visitors — up to a mile away. Image analysis software, such as that developed by the University of Southern California, distinguishes human from animal, and specialized software that uses a wireless network can alert rangers to potential intruders, reports NPR. The ability to see threats before they happen could save the lives of thousands of animals already headed for extinction.

Uncover Historical Clues in Paintings

For decades, art historians and conservators have been using infrared cameras to analyze paintings or validate their authenticity. The technique, called infrared reflectography (IR), works because many common pigments in paint are partially transparent to infrared light, revealing clues to what might be underneath. For instance, the camera may pick up so-called “underdrawings,” sketches the artist made before applying paint. Differences between the drawings and the final painting provide insight into the artist’s decision-making and ultimately, their creative process.

“When you see things with infrared light, you start to look at the painting in a different way,” Aaron Steele, an imaging specialist and photographer with the Detroit Institute of Arts, says in a video for PBS.

The same technique can be used to detect art forgeries, reports the Art Law Journal. One such forgery was that of the painting “Virgin and the Child with an Angel” by Francesco Francia (1450–1517). It was donated to the National Gallery in 1924 by a wealthy businessman who had purchased it from an art dealer. In 1954, another version of the painting came up for auction in London. In 2009, investigators examined both pieces of art using IR. Analysis of the underdrawings found that the painting that had surfaced in 1924 had been sketched using graphite, a material that wasn’t around when Francia was alive. It was the fake.

Who would have known hundreds of years ago that an invisible band of light would lead to technologies that help humans see the unseen? Most people associated infrared technology with military gear that lets soldiers see at night and pilots defend against guided missiles. But infrared applications extend into unexpected fields that benefit millions of people — and animals — worldwide.