Seeing in the Dark: The History of Night Vision
In honor of Military Invention Day, a look at night vision technology throughout the years
It’s hard to imagine the military without night vision technology, those goggles and scopes that make the blackest landscapes jump to life.
The history of night vision devices goes back to just before World War II, when Germany developed primitive infrared devices, and the Allies followed suit. These “generation zero” technologies amplified existing light about 1,000 times, but were bulky and cumbersome, necessitating infrared searchlights so big they needed to be mounted on flatbed trucks, making them easy targets for the enemy.
Throughout the 1940s and 50s, the Army worked with the Radio Corporation of America (RCA) to develop the technology further. By the mid-1960s, scientists had created what’s now referred to as the “first generation” of passive night vision devices, which didn't need an infrared illuminator to function. Devices like the small starlight scope were crucial in the Vietnam War, with soldiers often fighting in low-light jungle conditions.
The 1970s brought breakthroughs in thermal imaging, which was improved on through the next several decades. Night vision systems were a major part of Operation Desert Storm in the early 1990s, with one general testifying that the Army's night vision capability was the biggest advantage he had.
There are two main ways night vision can work. First, there’s image intensification – taking existing ambient light like moonlight or starlight and amplifying it through electrical and chemical processes. This produces the classic bright green image we’re familiar with from TV and movies. Then there’s thermal imaging, which captures the infrared energy emitted by people and objects. This has the advantage of working in utter darkness when there’s not even a touch of starlight to intensify, such as in a cave.
Today, night vision devices can amplify light by 50,000 times or more, and scientists continue to innovate. “The motto of our laboratory is ‘Conquest of Darkness,’” says Dr. James Bald, the special assistant to the director of the Night Vision & Electronic Sensors Directorate at Communications-Electronics Research, Development and Engineering Center (CERDEC), the Army’s technology development organization.
In honor of this weekend’s Military Invention Day, hosted by the Smithsonian’s National Museum of American History and the Lemelson Center for the Study of Invention and Innovation in collaboration with the U.S. Patent and Trademark Office, we’ve selected some images to illustrate the advances in night vision technology throughout the years.
Image intensifying systems
These “i-squared” systems, which take advantage of existing ambient light, give the classic green glow. Why green? “That’s the best color for the human eyeball—it doesn’t give you a headache,” says Bald, adding that green also provides good contrast.
Image intensifier systems work fine outdoors, where there’s almost always a bit of starlight or other ambient light to work with. But in total darkness you need a different tactic. All animals and objects give off some kind of heat signature, not just humans, but also plants, cars, rocks. We can’t see this, since our eyes don’t register the infrared spectrum, but thermal technology systems can.
A laser emitting infrared light can bounce off objects, lighting them up in the viewer. “You can light up a battlefield, as long as the bad guy doesn’t have [the same technology] too,” Bald says.
Airplane night vision systems
To use night vision systems from above, the sensors are mounted in a gimbal, a support that keeps an object in its center steady despite movement and vibration. The gimbal is mounted beneath the plane so the night vision sensors look down at the ground and capture images in the dark as the plane flies over.