Night vision goggles are a necessity when humans desire to intensify their sight in low light environments. It is only natural that our eyes do not possess the nocturnal capabilities of many animals. The only way he can see better in low light conditions is through technological devices such as night goggles. These are extraordinary vision enhancement tools that are used in the military, by sailors as well as pilots. What this implies is that night goggles are only necessary when humans need tactical advantage where illumination is low. But have you ever wondered how these extraordinary devices really work? If yes, then you need to continue to read on.
What kind of night vision do animals use?
The human sight is very powerful given that it can last for many years without necessarily becoming impaired. It also has a good range of distant objects, though not as good as those of some animals such as birds of prey. The main problem associated with the human sight is its inability to excel in the dark. We are not created to be nocturnal.
On the contrary, animals, whether nocturnal or otherwise, have better sight at night. The eyes of many animals contain a tissue called tapetum. This tissue performs the function of bouncing off light as it enters the retina. This makes light available to photoreceptors in their eyes. This enhances the night vision of nocturnal hunters such as cats, and sneaky animals like rodents.
How do night vision goggles work?
Light such as electricity and naked fire have made us more functional at night. But in the absence of these, the night vision goggles can come in handy. So, how do they work? Once dim light, which is made up of photons, enters the lens, they hit the photocathode. Through this sensitive surface the photons are converted to electrons which are multiplied by the component called photomultiplier. Thereafter, the photo screen receives the electrons, which creates flashes of light that gives a picture of the scene. Essentially, this is basic image enhancement. In other words, the conversion of the photons to electrons and multiplication of the electrons makes the images easier to see. But then, why are night vision green?
Why does everything look green through night vision goggles?
The color of night vision google is green. And the images they reveal also come out green. Disappointing, isn’t it? Well, there is a good reason why do not get to see colored image through vision goggles. Remember that these devices do not work in complete darkness. The dim light that is received by the photocathode still carries the images colors, albeit dimly. However, the conversion of photon to electron terminates all the information regarding the colors. What you should get is black and white. But it is green you get, right. Yes, that is because the photo screens are made of phosphors, which makes the images come out as green. The reason is that human eyes relates better with green light than black and white.
What if there really is no light?
If there is complete darkness, night vision goggles are powerless. This is because what they do essentially is to pick low light and intensify it for the eyes to see. The difference between the human sight and night vision goggle is that the latter can do a lot better in low light conditions. Both however share similarities in that they can will not work in zero-light environments. Is there another device that can work miracles in such environments?
Well, the one of the effective alternatives to image intensifiers is thermal imaging. Unlike devices like night vision goggles that rely on light to produce images, thermal imaging depend on heat. Sounds stupendous, right? Not really, if you can get a fair idea of how it works.