Military Technology- Nightvision

Nightvision is really a catchall term for any kind of system that can extend the range or acuity of someones eyes in low light or no light conditions.
Historically, many armies would not fight at night because the confusion, lack of quality and on time intelligence, and increased communication difficulty made night fighting a very dangerous and very risky proposition. Only the highest trained soldiers with a well rehearsed plan could take to the field at night with any clear chance of success.

One of the first technologies to enhance vision at night goes all the way back to the end of WWII.
Active Infrared involves using a light source that only emits light in the infrared spectrum ( as opposed to visible light) and a scope or camera that is sensitive to light in the infrared spectrum.

Active infrared night vision combines infrared illumination of spectral range 700nm–1000nm – just below the visible spectrum of the human eye – with CCD cameras sensitive to this light. When viewed through the goggles or scope, the scene appears as a greenscale monochrome image. Green is used because it is the easiest color for the human eye to perceive. Because active infrared night vision systems can incorporate illuminators that produce high levels of infrared light, the resulting images are typically higher resolution than some other night vision technologies. Lower cost commercial generation1 nightvision binoculars and scopes commonly use an active infrared light source to boost the range and effectiveness of their devices. Since active infrared light can be detected by any nearby enemy night vision goggles, it is no longer widely used military operations.
Another advantage of active infrared is that it can allow for enhanced vision in even a zero light conditions, in a cave or tunnel for example, since you are really bringing your own light source with you even though it is normally invisible.

US M3 Carbine with Active Infrared System

The next major component of Nightvision technology is Image Intensification. What we commonly think of as nightvision goggles are image intensification devices. The way it works is that IR light is converted to visible light on the screen. A more in depth way to say it is: that the IR light present in nature strikes a photocathode plate inside the vacuum tube and electrons are emitted and impact a microchannel plate that then illuminate the eye piece screen with a picture in the same pattern as the IR light that enters the tube. The image is said to become "intensified" because the output visible light is brighter than the incoming IR light, and this effect directly relates to the difference in passive and active night vision devices.

The first operationally efficient image intensifiers came online during the Vietnam War and were known as "starlight scopes" as they could be used at night with the stars as the only ambient light. Resolution could be poor and range was fairly limited. They did allow for trained soldiers to increase their ability to detect and engage hostile forces in low light, without giving any of those advantages to the enemy. The scopes were also heavy, fragile, and used batteries very quickly, which could be extremely difficult to replace in the middle of a jungle. Something better was needed.

PVS2 "Starlight" scope

The next generation of nightvision devices developed in the 1980's were lighter, more efficient and had a longer range. These "Generation 2" devices were first widely used in the First Persian Gulf War and were found to be one of the most important factors in the extremely one-sided fighting. Nightvision goggles (NVGs) were also heavily used, allowing soldiers to move, drive, and fly with greater awareness and safety than ever before. Light amplification is around 20,000x.

AN/PVS-4 Scope

AN/PVS-5 Nightvision goggles

Thermal imaging was first used by US Forces in the Korean War and has become more and more ubiquitous every year. Thermal Imaging works by displaying an image representing the difference in temperature of the objects and is usually in black and white and can switch between black or white as the "hot" color. Thermals are very useful in military operations as they can easily detect hidden or camouflaged personnel, and metal objects are often very easy to make out against the background, especially at night. Thermal imaging can also see through light rain, fog, and smoke that are impenetrable to other scopes. From Spy planes to UAVs to helicopters to infantrymen all the way to spy satellites, thermal imaging is in every branch of the military and will only continue to increase its prevalence.



Generation 3 Nightvision devices became common after the turn of the century and are distinguishable from Gen. 2 devices by much greater image resolution and much longer battery life. During this period mounts were installed on the soldiers' or Marines' helmets for a decrease in neck strain and increased comfort and utility. The light amplification is also improved to around 30,000-50,000x. Another innovation that became common in this period was the weapon mounted infrared laser/illuminator. These are known as the AN/PEQ 2 and their function is to allow a soldier to aim his weapon without having the ability to get a good cheek weld and use the iron sights. It operates by projecting a beam of infrared light in much the same manner as a visible laser sight, allowing for the soldier and his teammates to home in on a target. They are also used to coordinate air-to-ground fire.

AN/PVS-7 goggles and AN/PEQ 2

AN/PVS-10 Day/Night scope

One of the latest technologies to enter the fray is the AN/ PSQ-20 which is a combination Thermal Imaging and Image Intensification monocle for an image that combines the Thermal camera's abilities to see through rain, fog, and smoke as well as detect personnel and weapons with the image intensifier's ability for clear and detailed long range vision. Although it is not clearly visible in the photo, the newest military NVGs usually only cover one eye, usually on the weak side, leaving the other with regular vision, increasing peripheral
vision and enabling the soldier to perhaps use their weapon optics as well. Note as well the next generation infrared illuminator (AN/PEQ-15) mounted on this soldiers' M4. It is less than half the size of the AN/PEQ-2 and much lighter and easier to mount on a weapon without seriously affecting its balance.

AN/PSQ-20 Enhanced Night Vision Goggle