We, humans, are capable of creating inventions that enable us to do things that would have been otherwise impossible. We have pushed our limitations back, time and time again. When we can’t fly, we made airplanes. Telephones allowed us to talk to one another even when we are not in the same room. Night vision cameras came about for us to see better at night, and that’s what we’d talk about here–how night vision camera works.
Our eyes work like a camera. A basic camera has a sensor to detect light coming from the scene it is pointed at, and a mechanism to focus light onto that sensor. Cameras used to have films but now have electronic sensors. They are both light-sensitive materials that work by detecting the light that hits it. That light is focused on these sensors by using a pinhole or a combination of lenses to get a clear image.
Our eyes work the same way. We have the retina, which is the structure that light hits to form the image, and we also have a lens to focus the light onto the retina. These two complex apparatuses work by capturing visible light, so it does not work well in low light or in the dark. We are almost blind in during the night and in dark places.
During the day, we are exposed to the light coming from the sun, and we see everything that is hit by this light. At night, when the sun is out, we turn to other sources of natural light–the moon and the stars. We humans have used artificial sources of light when it gets dark. In earlier days, we relied heavily on fireplaces, torches, lamps, and candles. Now we have light bulbs, electric lamps, and light-emitting diodes.
All of these forms of light belong to a spectrum of light that we call visible light. These are what our eyes are capable of detecting. There are other forms of light, but those are the invisible one’s eyes. They are in a spectrum that our eyes are incapable of using for sight.
At night, the visible light that our eyes are sensitive to, is too few to create a clear sight. Regular cameras don’t work that well also, in low light or the dark. These are where night vision cameras come in. Detection and amplification of what we can’t see are basically how night vision camera works.
Light is a spectrum, and it has both visible and invisible light. Visible light is what we normally can see. But other forms of light such as x-ray, gamma-ray, infrared, radio, and ultraviolet are not. Regular cameras, like our eyes, can only pick up visible light. Night vision cameras are special because, aside from visible light, they can pick up infrared as well.
Night time is one of those scenarios where the light is really low, and pictures and videos don’t turn out that great. With minimal light to capture, images will not form well. The performance of night vision cameras does not suffer in these conditions. They were built precisely for these poor conditions.
At night, these cameras will pick up what available light there is, amplify that, and modify it into a form that we can see. This process is what’s missing in regular cameras, which we don’t have in our eyes as well.
Night vision cameras have sensors that are sensitive enough to pick up what little visible light there is, and also invisible light such as infrared. You often see these are black and white images or black and green images in screens. Low light and infrared light are not necessarily black and white, or black and green in reality, these are just the colors commonly chosen for output screens.
Cameras that make use of low light utilize light intensifiers. What they do is they pick up what visible light there is, and with the use of electric currents, power up the light that was picked up to make them bright. This will make the images brighter like you’re seeing them in daylight.
The eyes are not built for seeing infrared light. Some night vision cameras are designed to pick up infrared and transform them into images shown on monitor screens which can be seen. During night time, when there is no visible light, infrared may still be present which is why cameras that pick-up infrared can still “see” at night when our eyes can’t.
There are also night vision cameras that have infrared lights. These lights throw out infrared to where the camera is pointed at, making the scene brighter to the camera. It’s like using flash photography or using artificial light at night.
Our eyes can see well in the daytime and are virtually blind at night. There is minimal light when the sun has set. Artificial light sources were made so that we can move about at night with ease. When we want to see or when we want to take pictures and videos in places that are dark, we can use lighting effects such as flash or fixed bulbs. However, there are situations that call for visibility, and the ability to capture images, without the use of artificial light sources.
If you want to capture images of scenes that only occur at night, such as the activities of nocturnal animals, then you’d have to use night time cameras. Artificial light will disturb them and can disrupt what you are trying to capture on film.
Military and paramilitary forces which need to operate in night time conditions also utilize forms of night vision cameras. This allows them to see at night when in combat, and not use artificial lights. Artificial light, or visible light, can endanger them because opposing forces can also see this light, which can give away their position and maneuvers.
Infrared security cameras are used to record scenes in the dark, as acts of crime may be carried out in the dark. Without light sources, a regular camera would fail in this objective. Night vision cameras can record the culprit as they try to carry out their misdeeds.
These are just some of the more common uses of night vision cameras. There are more applications of these types of cameras out there such as hunting, farming, and rescue missions.