Night vision technology is one of the most important technologies that have a lot of advancements to provide an accurate view of the targets in dark environments and enhance your vision in low-light conditions.
There are different types of night vision technology used in imaging. Continue reading to know them.
What is Night Vision Technology?
Night vision technology is primarily developed for military personnel to detect enemy targets at night. And it’s extensively used by the military, law enforcement, navigation, and surveillance.
Though humans can’t be able to see in complete darkness because of their poor night vision ability, this night vision technology allows them to see in darkness or low-light conditions.
Since its discovery, night vision technology has well developed nowadays using their advanced technologies and it’s widely used in various applications.
Types of Night Vision Technology
Night vision technology is widely classified into three main types such as Low Light Imaging, Thermal Imaging, and Near-Infrared Illumination.
Night vision technology has various applications such as military, night security, and surveillance purposes, hidden objects detection, search and rescuing hunting, and wildlife observation.
Police and security often use both thermal imaging and image enhancement technologies, especially for surveillance.
Low-light Image Processing
It’s the technology to improve visibility in low-light environments. Low-light imaging technology uses a device called an image intensifier and it’s used to amplify the available light.
Most of the night vision technology works based on the use of the image intensifiers implemented in the night vision goggles and night vision scope products. The image intensifier works on night vision by amplifying the available lighting condition for attaining the better vision display.
How Does it Work?
This system works by gathering light i.e, photons through the objective lens over the photocathode of the image intensifier. where this photocathode is an electrode made from photosensitive material that emits electrons when light or radiant energy focussed on it. This photocathode converts the incoming photons into electrons through the photoelectric effect. The electrons freed by the photocathode that are accelerated by an electric field.
These accelerated electrons pass through the microchannel plate and strike the specially coated internal walls. This generates more electrons and creates a denser cloud of electrons constituting an intensified image of an original image. When the electrons strike the phosphor screen and make the phosphor glow. The light displays a brighter and desired image to the user.
The green phosphor screen is used in most of the applications as humans can differentiate green shades better than the other colors. The image intensifier is excellent for the low level of light sensitivity application such that it helps to enhance the visible imaging to the best possible extent. It consists of a high ability of resolution for the humans to trace out differentiations even in the low power state with an affordable cost.
Thermal imaging process
It’s the process of converting infrared energy(heat) into visible images even in low-light environments.
Thermal imaging uses a sensor to convert infrared energy into a visible light picture. This technology doesn’t require any sources of light.
It helps to identify the pictures in complete darkness and also works in smoke, fog, smog, and haze.
How Does it Work?
All the objects on the earth emit infrared energy, simply known as a heat signature. The thermal cameras or thermal imagers are used to detect and measure the infrared energy of an object.
These devices are a sensitive heat sensor to pick up the tiny variations in the temperatures. This thermal camera converts the infrared radiation into an electronic image for analyzing a particular scene or object.
These thermal imaging cameras can detect small variations in the heat as small as 0.01°C and thermal imagers display the shades of grayscale.
In thermograms, the hot temperatures are shown in brighter colors like red, orange, and yellow, and the colder temperatures are shown in purple, black/blue color.
Thermal Imaging technology has limitless applications such as transport navigation, surveillance, fire fighting, search and rescue, animals and pets management, healthcare & medicine, gas leak detection, and also used in aerospace, automotive, and chemical industries.
Advantages of thermal imaging
- Performs well in low-light and low visibility environments
- Thermal imaging produces a very fast and accurate measurement of objects which are arduous to touch/reach.
- This technology allows very safer and efficient methods of measurement.
- Routine maintenance using thermal imaging products helps in saving money and significantly lower the cost of escalating power bills, due to power outages, repairs, fires, etc.
Disadvantages of thermal imaging
- An image formed is of poor quality and is difficult to interpret in specific objects having erratic temperatures.
- Thermal imaging products are all at a High cost.
- Cannot be used for the study of underwater objects.
- Thermal imaging cameras cannot be seen through walls and also in the glasses because the thermal energy can return on shiny surfaces.
- Thermal imaging cameras typically only have +/-2% accuracy and worse for temperature measurement. It‘s not as accurate as contact methods.
Infrared illuminators or IR illuminators are a device that emits light in the infrared spectrum. IR illumination is invisible to the human eye and it ranges from 700 -1000 nanometers in the electromagnetic spectrum. An Infrared illumination works like a flashlight. All the night vision devices require infrared light or a small amount of ambient to work.
IR waves have longer wavelengths than those of visible light. The wavelengths that range from red-violet. Using the scattering and absorption, it can pass through denser regions of gas and dust in the space.
Infrared waves can’t be seen through the naked eye but to night vision devices like night-vision goggles or infrared cameras that allow us to see the infrared waves emitted from the objects such as animals or humans.
There are three different types of IR illumination devices and they are,
Incandescent lamps- These are high power lamps which are covered with an infrared filter. It allows IR radiations to pass and blocks out all other parts of the spectrum.
LED Lights- LED illuminators make use of a group of standard IR emitting LEDs. IR illuminator mostly uses an IR LED and the LED emits the radiations in the range of 760nm.
They are made up of Gallium Arsenide and these LEDs operate at 1.4v. An array of LEDs are included in the night vision security cameras to capture images in complete darkness.
Laser- laser types are more effective among the IR illuminators and these devices are based on IR laser diodes which create near-infrared energy. LASERs are expensive but provide the best quality images even at long distances.
Benefits of IR illumination
- They are Cost-effective
- It allows night vision to function in the absence of light.
- They are not affected by the surrounding lights.
- It allows seeing through the darkness, rainfall, mist, fog, and snowfall, etc. Also, it removes the inconsistency of ambient light.
- IR LEDs have a longer lifetime and low consumption rate.
Through this night vision technology, we can see the objects in the low-light environment and in the darkness. Today in the 21st century we have come in a long way in the development of night vision technology from the early 1940s. Though the Night vision technology has developed greatly since their introductions. It allows a lot of benefits for the military and law enforcement and also, helpful for surveillance and navigation. Initially, these night vision technology and devices were only used by the military personnel but now it’s available for the civilian uses too. Thus the present time night vision technology has become a part of our daily life.