There are various uses for night vision technology not just in the military but also civilian sector. A multitude of different outdoor activities is enhanced by the ability it grants the user to have a measure of visibility in the dark. As you may have guessed, night vision was originally designed by the military during the 40s and fully put to good use during the Vietnam and Korean wars. Back then, although they were high tech and the best that was available, the devices were very cumbersome and awkward to move.
When you think of night vision though, aside from military forces and hunters carefully and quietly watching their prey at night or security teams surveying their assigned post, you may well think of those green images that are generated by the technology. Why is it green? That is the question we are going to cover in this post.
Why Night Vision Images are Green?
To fully understand why night vision is green, you need to understand a bit more about the different technologies used in night vision. You will find them in night vision goggles, scopes, and cameras. There are three main technologies utilized in night vision and they are – Thermal Imaging, Active Illumination, and Image Intensification.
Let’s look at them individually first before getting back to the question of the green images.
Thermal Imaging is a technology that can read the heat signature of objects in comparison to its environment and other objects around it.
Active Illumination is a fairly straightforward technology, when image intensification is used (more on that in a minute), for night vision goggles or other viewing devices, there might be a need for a greater amount of light to properly process and render any images that are received before your eyes would be able to see them clearly.
Active illumination is used close to the infrared band and when more light is added into an environment, the devices using it are better able to harness it and convert it into the required image.
Although it has been mentioned several times already, it’s time to talk a little about image intensification and how that it’s the technology that is particularly responsible for the green images.
How Does Image Intensification Work?
When you look through an optical device that uses image intensification, it takes light emitted by stars and multiplies it. Now for where the green images come into it all. When photons in the light hit the device’s lens, they contain all the colors in the spectrum. Those photons are then transformed into electrons and all the data related to colors are converted into black and white in our brains/eyes.
At least that’s what would happen if phosphorus was not the material used for image intensification tech. If you know even a little about the chemical elements, you may know that phosphorus is green, and therefore when it presents images to you through those devices, it is a striking green color.