You might have seen the use of night vision goggles in many spy or action movies. Have you ever wondered, how night vision works? Have you thought how can this technology show us something our naked eyes cannot see? It’s amazing and interesting, right? Well, in this article, we are going to focus on the night vision system and how this technology works. We will dive deeper into the ins and outs of this technology with the use and application of night vision equipment. Keep reading.
What does it mean by Night Vision Technology?
Yes, it is true that with a night vision camera, googles, or binoculars, you can see throughout the dark. Even when it is a cloudy night without any shining moon in the sky, you can see a man standing up to 183 meters (200 yards) away from you. But, how is it possible? What’s working behind the scene of this miracle? Well, two technologies control the system. Any night vision goggles, cameras, or binoculars use one of these systems to develop the night vision environment. Let’s have some idea about the two technologies now:
Image Enhancement: This process collects every bit of light from around. It does not even skip the lower portion of the Infrared light spectrum. The infrared light spectrum is always present around us but not perceptible by naked eyes. The image enhancement technology amplifies the spectrum and lets us see any object in the dark effectively.
Thermal Imaging: Thermal imaging technology works a bit differently than the image enhancement technology. Unlike Image enhancement, it absorbs the upper infrared light spectrum. This kind of spectrum emits light according to the heat by the objects around. For example, any hotter objects like the human body will emit this kind of light more compared to any colder objects such as buildings and trees.
However, to understand the night vision technology or how night vision camera works; it is important to understand the Infrared light first. Let’s have a look at this topic now.
Infrared Light or IR light, in short, is a very tiny part of the light spectrum. The energy depends on its wavelengths. The shortest wavelengths come with the highest level of energy. When it comes to the energy of visible light, violet offers the highest energy, while the red offers the least energy. The infrared spectrum comes exactly after the presence of the visible light spectrum.
There are three kinds of infrared light around us:
Near-Infrared: With a wavelength range of 0.7 to 1.3 microns, Near-Infrared or Near IR light is nearest to the visible light around us.
Mid-Infrared: Having wavelengths of 1.3 to 3 micros, Mid-infrared light is generally used in electric devices like remote controls along with the near-IR light.
Thermal-Infrared: Thermal Infrared has the lion’s share in the infrared spectrum around us. It comes with a wavelength range of 3 to more than 30 microns.
How Thermal Imaging Technology Works?
As hinted above, Thermal Imaging technology follows a different process than the Image Enhancement technology, let’s have a look at the entire process in brief:
- There is a special lenses in this system. This lens is used to focus on the IR light emitted by all the objects around us.
- The infrared detector elements scan the focused light. A comprehensive temperature pattern called thermo gram is created by these elements. Building this pattern takes place within a very short period, even quicker than a second.
- At this stage, the thermo gram goes to create the electric impulses. The impulses are then transferred to a dedicated signal-processing unit to turn the elements into the data.
- When the third process is complete, the signal-processing unit delivers the acquired information to the display where the objects are visible as per the emission of the infrared.
When it comes to thermal imaging devices, they can scan any object for 30 times per second. They can sense from the very low (about -20 Celsius) to very high (2000 Celsius) temperatures. They come in two types: Cryogenically cooled and Un-cooled.
How Image Enhancement Technology Works?
Most of the night vision equipment you see around use Image Enhancement Technology instead of the thermal imaging technology. However, here is how this Image Enhancement technology works:
- Light and near-infrared light are captured by using a lens called an objective lens.
- The gathered light is then sent to the image-intensifier tube to convert the photons into the electrons.
- The electrons pass through the tube and hit a screen with phosphors. As the electrons remain in the same alignment, we get a perfect image of everything.
- The ocular lens magnifies the image for us to view. You can also use a display or monitor to see the images from the ocular lens.
Most of the Night vision device producers use this technology for the googles, binoculars, cameras, and other gadgets as well.
Generations of Night Vision Devices
There are five generations into which the night vision devices or NVD, in short, are categorized: The generations are:
- Generation 0
- Generation 1
- Generation 2
- Generation 3, and
- Generation 4.
Night Vision Equipment
Night Vision Equipment can be separated into 3 main categories:
Scopes: Scopes are handheld devices that are sometimes mounted on a weapon. You cannot wear them like goggles as they are monocular (made to be used by one eye). They are ideal for you when you need to look into a specific object for a few moments and then return to the normal view.
Goggles: When you need to view something constantly in the dark (inside a dark forest or building for example) with both of your eyes, goggles are perfect. Being binocular, they are wearable and they come either with a single lens or with a stereo lens.
Cameras: Some latest camcorders use night vision technology for capturing amazing videos in the dark. However, we hope that from the information given above, you now understand how night vision camera works. Night vision cameras are widely used in helicopters.
So, now that you know all the technologies behind the night vision devices, you should understand how night vision works. We hope that you will get benefitted from this guide by getting a clear idea of night vision.