Eyesight is your primary survival sense. To take away your ability to see is to take away your ability to attack, to defend, to react. Blindness is not just the ultimate vulnerability but, more ominously, it’s total ignorance of a threat.
We humans are hard-wired from millions of years of evolutionary selection to protect our eyes. Try not to blink when an object comes at your eyes. You can’t; it’s reflexive. Our most primitive instincts for survival, unchanged for over 200 million years, rely primarily on sight.
As children we were scared of the dark for the obvious reason that we couldn’t see. As adults, we’re still cautious in the dark. After all, we rely on our eyesight for 90 percent of our sensory input about our physical world, and when we’re blind, we instinctively feel like we’re in danger.
Darkness is foreboding even for well-armed, well-trained, well-prepared professionals, and that’s why the ability to see in the dark is so important for those who go in harm’s way.
The first time that the U.S. military ran up against a real problem with fighting in the dark was in Vietnam. Certainly there had been nocturnal activities in World War II— the Normandy Invasion was launched at night and a lot of OSS and other “commando” missions were conducted under the cover of darkness— but for the most part, the World War II battlefield was an 8 to 5 affair. Korea was also a conventional war. It wasn’t until we entered the rain forests of Southeast Asia that we encountered a predominantly unconventional war in which the enemy only came out at night.
The U.S. military had dabbled with night vision systems prior to Vietnam, and actually began research in the 1940s, but it wasn’t until 1965 when the U.S. Department of Defense established its own Night Vision Laboratory that we became serious about seeing in the dark.
The first systems, fielded in the 1950s and ‘60s, were “active” systems that relied on a artificially supplied infrared light to function. These systems were incredibly cumbersome and ineffective. Retroactively referred to as Gen 0 night vision, these primitive devices used truck-mounted infrared searchlights and tripod mounted viewing devices. They basically didn’t work.
When we found ourselves confronted with triple jungle canopy where hardly any moonlight penetrated to the forest floor, and an enemy that slept during the day in a warren of underground tunnels, the government funded a high-priority R&D project to develop “night vision” devices.
ITT Corporation of Roanoke, Va., began producing night vision devices for the military in 1958. The first viable unit was called the Starlight scope, a large and cumbersome rifle sight. The Starlight scope was the first true “passive” night vision system that used only ambient light—light from the infrared spectrum reflected by the moon, stars and sky—and not artificially supplied IR. (Systems that rely on artificially supplied IR are called “active” systems.)
How Night Vision Works
Designated as the AN/PVS 2 night vision device, the Starlight scope was a curious blend of optics and electronics. (The acronym “AN/PVS” stands for “Army Navy Passive Vision Sight.”) The optical element was made from millions of hair-fine fibers of optical glass, combined with a phosphor screen and a gallium arsenide micro-channel plate. It’s all very complicated, but the key is the bundle of glass strands, the heart of conventional night vision. It’s called an “image intensifying tube.”
Light enters the device through an objective lens, just like on a conventional scope. The lens focuses the light into the image intensifying tube. The tube is highly sensitive to contaminants, which appear as splotches or dark spots on the image, one of the main reasons that tubes are sorted and graded in the final inspection stage. The tube must be made inside a sterile vacuum to prevent dust motes and other contaminants from getting inside the tube.
Inside the tube assembly are the electronic components: a photo cathode, a power source, a micro-channel plate, and a phosphor screen. The photo cathode absorbs light energy in the form of photons and converts the photons into electrons. The electrons are multiplied thousands of times as they pass down the tube, by a wafer-thin instrument called a micro-channel plate.
The electrons then hit a phosphor screen. The phosphor screen reconverts the electron image into a light image, and focuses it on the output window. The resulting image is green and somewhat grainy.
There were lots of problems with tubes. The first and foremost—a major Achilles heel of the technology—is that the tube cannot discriminate between light sources, such as a bright source or a dim source. The tube amplifies all light and if it’s exposed to an already bright source, such as a headlight or a street light, it “blooms out” or over-saturates with light. This not only ruins the view, but also it permanently damages the device, creating “burn spots” in the phosphor screen.
Another big problem with tubes is that the manufacturing process is highly inconsistent. In fact, the tubes vary so much in quality that the two main manufacturers, ITT and Litton (now Northrup-Grumman), grade them like diamonds. There are a host of inherent manufacturing defects in tubes, from dust particles creeping inside to the glass fibers being out of spec.
The good tubes that pass Mil Spec go to the military; the rejects are sorted again and sold to various commercial customers. All the Gen III systems you see on the Internet are made from rejected tubes, sold to companies that put the tubes into various housings, some identical to military models such as the AN/PVS-14 or AN/PVS-7B.
Tubes suffer from a variety of optical issues, such as “scintillation,” a sparkling effect that degrades the image quality. Many have “holes” or small, white blank spots throughout the image.
Oh, and there’s one other issue: service life. Tube systems have a service life of around 2,000 hours. You have no way of knowing how many hours a given tube has on it when you buy it.
All of the night vision devices that the Army’s Night Vision Lab military designated as Gen I, Gen II and Gen III rely on tubes. The “generations” differ only in their performance to intensify ambient light, not in their intrinsic technology. This is a very important point because, as we’ll see, it’s only when you get into digital night vision systems that you can overcome the problems of tubes.
Smart Night Vision
A tube is a “dumb” or analog system— there is no ability to process or refine the “information” that comes through the tube. What you need to operate in a tough urban environment, obviously, is a “smart” or digital system.
A patented new digital night vision device called SuperVision™ recently was introduced that was designed specifically to address the needs of cops and warfighters in a typical urban environment with its widely varying degrees of shadows, light and dark areas, everything from a shopping mall parking lot to the proverbial dark alley.
SuperVision also solves two other problems of tube systems, the general lack of resolution and clarity and its characteristic grainy green look and also the lack of magnification to get a clear facial ID on a subject or read a license plate at a distance.
SuperVision utilizes the most sophisticated CCD (charge coupling device) sensor available anywhere in the world and couples it to the company’s proprietary digital signal processor (DSP) to reveal unimagined levels of detail and clarity from the night. The resolution on SuperVision’s display is so good it’s actually the same quality as a High Definition TV!
What this digital night vision technology gives you is a “smart” device that can discriminate light from dark, bumping up the pixels from the inky blackness around a dumpster in shadowy fringe of an industrial center while at the same time harmonizing the sudden glare of a car’s headlight turning into your view. No blooming, no whiteout, just clear, sharp black and white images.
And then there’s the zoom magnification feature which allows SuperVision to zoom from 2x to 8x for clear subject ID or other important detail resolution.
SuperVision is easy to use. There’s an on/off button and two sets of controls, one that adjusts the gain in three different lighting modes, dark, light and normal, and the zoom adjustment from 2x to 8x. All are rubber coated waterproof switches ergonomically placed on the unit’s top where your finger naturally fall.
Perhaps the best feature of all is SuperVision’s affordable price. Thanks to the “electronics revolution” with everything from iPods to cell phones driving the price of microprocessors and chips down, SuperVision retails for $1,399… about a third the price of a Gen III goggle.
I tested one of the first SuperVision units to leave the Carlsbad, Calif. factory with three members of the Oceanside (Calif.) PD’s tactical team. On an overcast night with about a quarter moon, the results were unbelievable. The resolution and clarity amazed us all, especially the ability to distinguish facial features enough to get a positive ID at 100 yards.
“It’s clear as daylight. Everything’s so detailed. It’s not that fuzzy green look. It’s black and white, sort of like watching the Andy Griffith Show,” said one tester.
“Oh wow,” said another tester when he first looked through SuperVision. “This is amazing!” After we got over the oohs and ahhs, we watched pedestrians from a rooftop and were easily able to distinguish them at 300 yards. When car headlights or streetlights came into view, there was no hint of blooming. We looked at light and dark areas, like a wooded clump of bushes next to a streetlight, looking carefully to see if we could see into the shadows. We could.
One of the guys had a PVS-22 for his sniper rifle and the difference was, no pun intended, like night and day. The image intensifying tube system could not discern into shadows next to a streetlight at all. The streetlight bloomed the tube so badly that you couldn’t even tell there were bushes beneath it.
For law enforcement applications, digital night vision technology is simply a better mousetrap, a mousetrap designed for urban lighting conditions, not a jungle canopy. And for a third the price of the tube systems, it’s a no-brainer.
The other weaknesses of tube systems also disappear with digital technology. For instance, there’s no service life issue since digital sensors are not subject to degradation over time. Second, there is no “blooming” to either damage the electronics or wash out the image. Third, you can drop it on concrete and if something does break, it’s a relatively inexpensive matter of replacing a circuit board. You break a tube and you’re looking at $2,500 to $3,000 to replace it.
Just as Aimpoints and ACOGs have replaced iron sights on combat rifles, look for digital night vision to obsolete the tube systems. Eyesight is too important to our survival to rely on old technology.
Eyesight is your primary survival sense. To take away your ability to see is to…
by William Bell / Sep 1, 2007