How does Night Vision Cameras work?

There are a few different types of night vision cameras that work on different principles but the main concept is that the night vision camera ‘’floods’’ the area with invisible light that the human eye isn’t capable of seeing without a geared eye but the camera lens can – for example a person in space will see pitch black while in the same time a camera has the ability to film with perfect clarity due to that mentioned invisible light.

If you’ve ever taken a look at a night vision camera, you’ve noticed that it’s covered in a few small LED bulbs. Those LEDs are projecting IR light. The idea is, when dark those LEDs project IR light “invisible to human eye” and act as source of light to the camera.

Furthermore, night vision footage always look black and white. Why is that exactly? This is because people cannot differentiate between black and white as they can differentiate other color shades like blue or green for example. In consequence, most night vision cameras switch to a monochromatic filter that makes it much easier for people to see the actual image.

Types of night vision cameras mentioned.

Let’s take a look at the 3 main types of night vision cameras and each’s benefits – Low-light night vision cameras, Infrared (IR) night vision cameras and Thermal vision cameras. Let’s take an even further look into each one as this will help us better understand the way each type of night vision camera works.

IR night vision camera

As a fun off-topic fact, it was actually discovered in 1800’s and was way ahead of its time. The IR night vision camera is basically an invisible band of radiation at the lower end of the visible lighting Spectre.

With its wavelengths ranging from 750NM to 1NM, infrared light or IR for short starts at the very end of the microwave spectrum and ends on the beginning of the visible light spectrum – the IR colors range from wavelengths of red to violet.

Most IR based night vision cameras come with a built-in infrared LED that provides the user for best quality night vision footage even while in a very low lighted and even no-light at all condition – but that is actually the purpose of those cameras isn’t it? One of the most important features of every IR-based night vision camera is the Infrared Cut filter or Cut removable.

What exactly is a Cut Filter or also called Cut removable?

It is basically a cut filter that has a mechanically shutter design. It is a small piece that is placed between the lens of the camera and the image sensor itself. It’s usually controlled by an electric motor or an electromagnet.

Those filters are used with CCD or CMOS cameras to produce the most accurate color image possible. An IR cut filter purposely blocks out the transmission of the infrared light while only passing the visible light. If the filter is turned off – infrared light will get to the camera, making images into a black and white mode.

The benefits of an Infrared Night vision camera.

Unlike the low-light night vision cameras, the Infrared cameras have the possibility of recording in a pitch-black condition without any and all additional light. The cylindrical shape of the infrared LED lights provides infrared illumination during the night for the camera to be able to capture an image. The big advantage of IR cameras over the other two types is that it has to be the cheapest of night vision cameras on the market while in the meantime they use the less energy and are very efficient at their job.

Thermal Night Vision Camera.

The thermal night vision camera has a special lens and offers the feature of passing infrared energy through it. Then the focused light hits a sensor that scans information and draws this information from the several thousand points in the camera’s field of view of FOV for short.

With all this process happening in a millisecond, a temperature pattern also known as thermogram is being created, which to be precise, requires only one thirteenth of a second to develop. The thermogram then transforms itself intro electrical impulses, which are mainly directed to a signal-process unit that then translates this acquired information into visual data.

In consequence, the created image displays as different colors that correlate to themselves as well as to the amount of infrared energy emitted. It is that combination of factors that create the image that most emergency professionals actually rely on for the protection of people. Thermal night vision uses heat is its main light-finding source instead of intensified light like low-light night vision cameras. Unlike low-light and Infrared night vision cameras, the thermal vision camera can see through everything, no matter the light level.

Even in total darkness, foggy, stormy and very poor weather conditions, the thermal image technology allows users to detect any object that radiates heat at great distances. The ability to see over a much longer distance than normal night vision cameras is a very big advantage over its counterparts.

In short – the thermal night vision camera can see heat instead of light. The more heat a certain object generates, the more thermal contrast it gives back to the camera and the easier it is to be seen on screen. With that in mind, when thinking about it, everything on earth has a certain heat – people, animals and ever cars generate quite a lot of heat in a different way. This is why it is easier for those objects to be detected with the thermal night vision even if the weather conditions don’t allow us to use any other type if night vision camera.

Benefits of the Thermal Night Vision Camera.

Thermal night vision is the main solution that addresses visible image contrasts at night. When a certain target is brighter than all of its surroundings, it has a very good visual contrast and is much easier to be detected. On the other hand, when the object doesn’t have a good visual contrast, it cannot be distinguished from most of its surroundings. It is not possible for any night vision camera to reveal a specific contrast when it’s just not there.

Unlike the other types of night vision cameras, thermal night vision cameras are immune to specific third-party interference – smoke, dust, anti-CCTV surveillance like reflecting, visor or infrared laser glasses.

Low-Light Night Vision Cameras.

Those cameras can also be referred to image intensification cameras. The technology is upgraded from what it used to be in the past decades. The low-light night vision technology relies on increasing image intensity and this way deliver a cleared and even colored picture to a very low-light atmosphere – that’s where its name comes from a Low-light night vision camera. But how exactly does this intensifying process happen?

The image intensifier is basically a vacuum-tube based device or also called a photomultiplier tube that can generate an image from a very small number of photons as simple as the light from the stars in the sky, so in consequence a very dim-lit by the naked eye area appears very light up on the night vision camera.

When light gets to a charged photocathode plate, the electrons are transferred through a vacuum tube that strikes the microchannel plate and causes the image screen to literally ‘’illuminate’’ with a picture in the same pattern as how a light strikes the photocathode, but is on a high frequency that the ungeared human eye cannot see. In the process the image is said to become ‘’ intensified ‘’ because the output of the picture itself is now brighter than the incoming light. However, these cameras still need some light to be able to produce a colored image.

Benefits of a Low-Light Night Vision Camera

Although low-light night vision cameras aren’t exactly NIGHT VISION and require some visible light in order to do their job, they still remain extremely good at what they do because they outperform IR night vision cameras. They are the only security cameras that can be able to produce a colored image in a low-lighted condition.

The other advantage over the two other types of night vision cameras is that is very affordable.

In conclusion, the night vision cameras are excellent and VERY complex tools that are mandatory if you want to have a night-vision surveillance of a specific area. It is very important to choose an adapted night vision camera for the specific condition it is going to be used in.

Related Questions

Can a camera see in the dark? – Typically, not every single camera has the option to see after the sun goes down. There are specific cameras – night vision cameras that have built-in LED bulb illuminators that project infrared light unseen to the human eye, but giving the user of the camera a clear picture even though it is pitch black to an ungeared eye.

How do I know if my camera has night vision? – The fastest and simplest way you can check if the specific camera has the ability to see when its dark outside is to check the area around the lens. If there are specific LED bulb illuminators or small red lights around the lens it means that the camera HAS night vision.

Can night vision cameras see in complete darkness? – Some can while others cannot. If it is a low-light technology night vision camera it is necessary for it to have a minimum source of light so it can produce a picture. The other types of night vision do not need any light to produce a picture – they either need thermal objects in the field of view of the camera or just the simplest night light like the moonlight and starlight and use those natural light sources and greatly amplifying them, giving the user a very clear night vision picture.

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