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Our eyes see reflected light. Daylight cameras, night vision devices and the human eye all work on the same basic principle: visible light energy hits surfaces and bounces off of it, a detector then receives it and turns it into an image.

Night vision works by amplifying visible light in the immediate vicinity. Thermal imaging uses infrared sensors to detect temperature differences between objects in their line of sight. Night vision enlarges the light in a scene and converts it to green-tinted or white-tinted images, depending on the phosphor used inside the tubes. These detectors must receive enough light to create an image. Although there isn’t any sunlight to bounce off anything at night, these night vision devices are dependent on light provided by starlight, moonlight and artificial lights - like IR torches.

Futurama offers an extensive range of night vision products, we are official resellers of Pulsar, FLIR Systems, AGM Global, Infiray, Hikmicro and many more world-class brands.

There are 3 different types of night vision: image-intensified night vision, digital night vision and thermal vision.

Image-intensified night vision uses IITs (Image Intensifier Tubes) to amplify the ambient available light by between 1200 and 30,000 times. Image intensifying tubes are available in different image quality divisions, better known as “Generations”.

Generation 1 amplifies the ambient light by around 1200 times, Generation 2 amplifies the ambient light by around 18,000 - 20,000 times. Generation 3 units amplify the ambient light by around 30,000 times. Generation 1 is thus your entry-level, Generation 2 being better than Generation 1. As you go up Generations the low light sensitivity and resolution gets better in the unit.

In South Africa Generation 1 and Generation 2 is available for civilians. Generation 3 units are only available for the military and law enforcement. Another very important point is that ALL users have to have an end-user declaration.

Image intensifier tubes capture the light through the objective lens in the form of photon energy. Inside the night vision ITT device the photons then get broken up into electrons that bounce off optical lenses on the inside of the device. The electrons then get sped up inside the ITT device which increases the energy of the electrons. The higher energy potential intensifies the ambient light that enters the device. The electrons then fall onto a phosphor plate closer to the optical lens of the device. The phosphor plate is either white or green - the image gets displayed in either white or green depending on the phosphor used in the device.

Digital night vision is a newer form of night vision. The price-point makes it more accessible to the everyday user and people who are looking for entry-level night vision to get into the night vision scene. This newer technology utilises a digital camera CCD or CMOS sensor that is sensitive to near-infrared light (790 nm – 940 nm). Digital night vision does not amplify the available ambient light, instead, it relies on IR illuminator flashlights to see in the dark. An IR illuminator is a type of flashlight or LED that only emits light in the infrared range, this light is not visible to the human eye, but night vision devices can detect it.

Thermal imaging cameras are altogether different. We call them “cameras” but they are sensors. Thermal vision uses a type of sensor called a Microbolometer Focal Plane Array to create pictures from heat, not visible light. Heat and light are both parts of the electromagnetic spectrum, but a camera that can detect visible light won’t see thermal energy and vice versa.

Thermal cameras detect more than just heat, they detect tiny differences in heat – as small as 0.01°C and display them as shades of grey or in different colours. Everything we encounter in our day-to-day life gives off energy. The hotter something is the more thermal energy it emits, this emitted thermal energy is called a heat signature.

When two objects next to one another have different heat signatures, they show up quite clearly to a thermal imager regardless of lighting conditions.

Thermal energy comes from a combination of sources, depending on what you are viewing at the time. People, warm-blooded animals, engines and machinery for example – create their heat, either biologically or mechanically. Other things – land, rocks, buoys, vegetation – absorb heat from the sun during the day and radiate it off during the night. Because different materials absorb and radiate thermal energy at different rates, an area that we think of as being one temperature is a mosaic of subtly different temperatures. The camera then gathers information to help create a thermogram made from temperature patterns that have been detected. This is then transferred into electric impulses that can then be translated into data for us to see on the camera's display.

A very important point to be aware of is that a thermal camera detects hot and cold spots on a scene the device is looking out on. Any deviation of temperature will be shown, whether being higher than or lower than the median thermal energy collected. Thermal sensors cannot see through glass, nor can they detect energy through a wall.

Thermal Cameras come in different resolutions. The higher the resolution and sensitivity are, the more expensive the unit will be. The resolution of a thermal sensor accounts for the quality of the image the user will experience.

You also get 2 different kinds of displays for these thermal cameras, namely LCOS or OLED

LCOS – (liquid crystal on silicon) is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also referred to as a spatial light modulator.

OLED - organic light-emitting diode, also known as organic electroluminescent diode, is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound that emits light in response to an electric current.

For the user, the OLED display will be more comfortable on the eye as LCOS displays have a continuous backlight that is shined onto the display.

The common purpose of night vision devices was to locate enemies and targets at night. Today, night vision devices are used for everything from military applications to navigation, wildlife observation and entertainment. Various scopes, goggles, binoculars and monoculars were made to help you stay safe and be one step ahead of your enemy. Although these devices use the same technology, before you make a purchase, contact Gavin our night vision specialist at 021 851 3284 or [email protected] so he can help you find a device that is suitable for all your needs.
 
Bibliography
FLIR. (n.d.). What’s The Difference between Thermal Imaging and Night Vision?
Marais, E. (2023, July 26). Night Vision .
Futurama. (n.d.). Retrieved from Futurama: https://futurama.co.za/how-to-buy-night-vision/