At night, there is no absolute darkness in an open area: the stars and the moon are shining, and the city lights can be seen. This light is not enough to know the environment in detail. But it is enough for a night vision device: it captures the background infrared radiation from objects, amplifies it, and converts it into a visible image.
Many have noticed more than once in films and computer games what a night vision weapon looks like. For some reason, it is green. We will tell you why it is green.
Night vision scopes are devices similar in structure to monoculars, which are fixed or screwed onto weapons. The range of vision coincides with the scope itself, which is usually about 300 meters. These scopes can be used in the daytime as well. With their help, excessive brightness is silenced, and the goal becomes more tangible and real.
The human eye sees poorly in the dark because the human body is tuned to sleep at night. It is difficult for people to see something in the dark without light. Using flashlights is too noticeable, so you can’t go unnoticed. But the night vision device will help you remain unnoticed and see the object well in the dark.
They are needed for observation and patrolling at night. They also are widely used by law enforcement agencies in search or rescue operations. With the help of night vision, you can find evidence, but they only give the outlines of objects – it is almost impossible to identify people with night vision devices.
Night vision devices appeared in Germany in the middle of World War II. The first devices were bulky, operated at a distance of up to 150 meters, and could not do without an infrared illuminator. They were installed on tanks and helped the movement of the columns. More compact devices appeared by the end of the war – mobile night sights. They worked at distances of up to 100 meters and weighed, together with batteries for the illuminator, more than 30 kg.
Nowadays, night vision devices are designed for use in the dark. Such devices are top-rated for hunters, night reconnaissance combat operations. A night vision device consists of the following parts:
a radiation receiver,
image display device.
In many modern night vision devices, the role of a radiation receiver, an amplifier for displaying an amplified image, is performed by an image intensifier. The operator examines the idea on the screen through an eyepiece. A particular matrix can be used as a receiver. In this case, the operator observes the image on the monitor screen.
Modern night vision devices are pretty compact and easy to use. Now there are many different versions of night vision devices.
The most challenging area for observation is the forest. There are many foreign objects. If a person is wearing baggy, voluminous clothes that hide the outlines of the body, and he moves slowly or does not move at all, then it isn’t easy to see him. Moreover, a camouflage uniform does not make a person invisible to a night vision device. An exception is a digital camouflage: its pattern consists of small rectangles (pixels), there is no sharp contrast of colors. It is not easy to notice a soldier in this uniform, even with the help of technology.
Why is NV green?
The characteristic green tint is present in the image for a reason.
First, device manufacturers experimented with several different colors and found that the different hues that make up a monochrome night vision image are most accurately perceived and distinguishable when green.
The second reason is that the human eye can distinguish more shades of green than any other color, which makes it easier to see objects in the image.
The reason that the human eye perceives a vast number of shades of green lies in evolution. Green is the most widespread color in nature due to the processes of photosynthesis. Our distant ancestors lived and hunted in the forests, so they had to adjust their vision to timely notice danger or track down game among the green foliage.
This ability was passed from generation to generation, continuously improving until it could distinguish hundreds of shades of greenery and see even a slight movement among leaves or grass.
It is also the green color considered the most pleasant for the human eye, calming the psyche. It relates to wildlife, life, hope, rebirth. Green is a sign of safety,
The third reason is that the human eye gets less tired from the green than white.
Eyes get tired from night vision devices and any optical means. When the observation ends, you need to sit with your eyes closed for a few seconds. Otherwise, you can betray yourself – the whites of the eyes in the dark shine with a greenish light.
We can conclude that night vision device are green for the convenience and comfort of their use. Since human eyes get more tired at night, green color helps to reduce fatigue, all because surveillance is quite a long process.