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Types of Night Vision, How It Works, Useful Tips

Night vision is generally considered as the ability of seeing in the night, but this is only partially true. With the boost of intensity range along with a spectral range of available light with heat imaging, the prospects of night vision are also enhanced.

Every object is emitting infrared radiation ut it doesn’t catch the naked human eye. The two main technologies involved in night vision are explained below:

 

Low-light imaging

This technology is used for improving visibility in areas that are dimly lit. The most common method of this technology makes use of a device termed image intensified which helps in amplifying the available light. Let’s see how an image intensifier works with low-light imaging.

 

  • In the first place, the available light focuses via an objective lens that remains closest to the object to be viewed. It moves on to a light-sensitive surface called photocathode which emits electrons.

 

  • An electric field accelerates the electrons which are generated by the cathode.

 

  • Next, these electrons that have been accelerated move to the holes present in the microchannel plate. They bounce off the internal walls for the generation of more electrons through this action of bouncing.

 

  • Finally, the electrons successfully hit the phosphor screen which, in turn, makes it glow.

 

  • This light eventually displays the right view to the user or to the attached device.

 

Thermal imaging

This technology works by capturing the upper part of the infrared light spectrum that’s emitted in the form of heat energy by different objects in place of directly being reflected as light. The temperature of the object is determined by capturing the various levels of infra-red radiation. Even though it is not possible to see in the dark, but its presence can be felt as heat when the intensity of the light is adequately high.

 

  • A specialized lens works by focusing the infrared light that’s emitted by various objects.

 

  • The focused light gets scanned by the array of infrared detecting elements and they create a minute temperature pattern known as a thermogram. This data is procured from several thousand points in view.

 

  • The thermogram which stems from the detector elements gets translated into the electric impulses.

 

  • The signal processing unit receives the impulses. This unit is a circuit board containing a dedicated chip that translates the data from the elements for display.

 

  • The signal processing unit allows the processing of this data for displaying where it appears in the form of different colors based on the intensity of the emission. The combined forces of all impulses help in creating the image.

 

Binoculars

Binoculars may not come with a hands-free advantage of goggles but the major advantage of these devices is the magnification. Binoculars are known for making distant scenes to appear closer, but the exact amount of closeness that you will see is dependent on the make and model you choose.

Binoculars typically work by intensifying ambient light from sources such as moonlight or street lamps. Night vision binoculars are designed specifically for this purpose, with an infrared illuminator that amplifies light from these sources.

 

Even though premium-grade night vision binoculars are available for professionals, they also come in consumer-grade models which are crafted for recreational purposes like hiking or hunting in the dark.

Some of these can also be attached to the top of the hunting rifles. As it goes with night vision goggles, the scopes are widely used in the law enforcement sector and military forces.

Note that you may need a tripod to use your night vision binoculars effectively. If you’re surveying a field of crops on a farm, for example, it’s best to set up the equipment on something stable so that you don’t have to hold it yourself while viewing through the lenses.

Binoculars, as well as monocular devices, are made using both thermal imaging and image intensifying models. When it comes to hunting using night vision binoculars, thermal imaging is particularly useful since animals naturally generate a lot of heat.

 

Camera

If you have seen the front part of security cameras, you may have noticed that it remains covered with tiny LED bulbs which are referred to as the IR lights. When it is absolutely dark everywhere, these lights are turned on and they function as a flood of light that douses the field of view with infrared lighting.

 

The best part aspect about infrared lights is that it is totally visible to the naked eyes. Moreover, night vision footage from any camera always comes in black and white since these two hues can be easily differentiated by human eyes rather than a broad spectrum of colors.

As a result, you will see that all night vision cameras switch to monochrome hue when there is inadequate light so that it becomes easier to see these colors rather than the usual RGB shades.

 

Microscopes

A microscope is an instrument used to see objects that are too small for the naked eye. It has single or multiple lenses with high angular magnification. Night vision microscopes use a process called secondary electron detection to produce enhanced images in the dark which makes it easier for scientists and researchers to see what they’re working on easily even at night or in areas with low lighting.

 

Microscopes are commonly used in military, police, and security operations to detect tiny traces of explosives on clothes of criminals, nuclear forensics, detection of contraband such as drugs and precious stones, counterfeit currency detection, etc. They can also be a valuable asset for doctors who need a deeper look at the human body to detect cancer cells, parasites, infections, etc.

How does night vision work

For understanding night vision, it is crucial to have a clear idea about how light works. The energy amount contained in a light wave has a link with its wavelength and the shorter the wavelength, the higher will be the energy. Of all the visible lights, violets contain the maximum amount of energy while red has the least amount.

There are two types of similar technologies being used in equipment specified for night vision. Conventional devices utilize optoelectronic image enhancement that functions by sensing minute amounts of infrared lighting which gets reflected off various objects. Then the light gets magnified electrically into a glowing image with a greenish hue.

Using a technology called active infrared illumination, which is projected onto objects and then captured by sensors. A computer chip determines what’s on-screen, amplifies it, and then displays it on the eyepiece. This process makes it possible for us to see clearly at night or in dark places where there isn’t much natural light available.

 

On the other hand, a comparatively newer technology known as digital image enhancement works by capturing the light that’s available on the light sensor. Later, it is digitally enhanced for forming images in a completely colored display.

 

All devices pertaining to night vision are categorized by the generation in which they were produced. This refers to the kind of image intensifier tube that has gone into the making and that which produces the image finally. The 1st generation devices are typically most popular and known for creating bright and sharp images at a reduced cost.

 

Next comes the 2nd generation device that is available with the professional and high-end devices used by the armed forces or police. Nevertheless, they are costlier compared to the 1st generation devices.

 

Finally comes the 3rd generation devices which are considered the ultimate in the world of night vision devices. It uses gallium arsenide for endowing a sharper and crisper image. It goes without saying that these devices are far expensive than the previous inventions.

 

Uses of night vision devices

A night vision device is an equipment containing an image intensifier tube placed in a rigid casing and it is most commonly used in military service. In recent times, this technology has also come to be used widely by civilians. For instance, enhanced vision systems are now used in aircraft for the augmentation of the situational awareness of pilots for preventing accidents. These systems are also included in the avionics package and the US Navy has also started procuring night vision technology into helmet-mounted displays also.

 

A particular type of night vision device is the night vision goggle containing two eyepieces. This device makes use of any one intensifier tube where the same image is sent to both the eyes. It is often combined with magnification lenses which constitute the binoculars.

 

Night vision systems are also installed in some vehicles. For instance, automotive night vision technology is very helpful in improving the driver’s perception of distance and the various objects in darkness. In these systems, infrared cameras are mostly used and they are often combined with active illumination techniques.

This helps in collecting data that gets displayed time the vehicle driver instantly. These systems are presently given in certain optional equipment on some premium-grade vehicles.

 

The main point of difference between generations of night vision lies in the intensifier technology. The first generation was developed in Vietnam and it is now recognized as entry-level.

In this kind of night vision device, an intensifier tube is used for amplifying ambient lighting with the acceleration of electrons that further strikes a green phosphorus surface.

 

Origin

Night vision has been around for a while, and we use it to see in the dark. It works by amplifying light that’s already present. Night vision technology has been evolving for years, but its most recent development was back in 1995 by Dr. Ralph Haughley of BAE Systems Applied Intelligence at Malvern Technology Centre. He used liquid crystal on silicon chips embedded within the lens of a camera obscura device fitted with infrared LEDs which gave an image on the chip.

The image was then enhanced by software to produce the final result. Dr. Haughley’s device works in complete darkness can be switched on and off at will, and is smaller than the size of a box of matches.

Night vision devices have come a long way from this point and the latest version was released in the 2000s.

Digital night vision devices cannot be damaged even by the presence of natural lighting, which implies that they can be used both at the night as well as day.

 

The best solution for finding a suitable night vision device ultimately boils down to how you are going to use the device and which features do you require the most. For instance, thermal is best suited for the purpose of detection as it helps in quickly noticing objects that remain hidden from naked eyes.

 

Uses of Night Vision Devices

1. Military personnel use night vision devices during operations when there is a minimal level of light present in order to enhance their vision and be able to detect threats from a distance.

 

2. Police officers use night vision devices when looking for suspects at night or in areas with minimal lighting so that they can see what’s going on clearly without being detected themselves.

 

3. Hunters use night vision devices to spot animals from a long distance and take them down humanely with minimal collateral damage.

 

4. Security personnel can use night vision goggles when doing patrols or checking for trespassers at night so that they don’t have to switch on lights and alert everyone in the vicinity about what they’re doing.

 

5. Hikers and campers can use night vision devices in order to explore trails or check the layout of their campsite when there is little to no light available at night.

 

 

The technology used for Night Vision Devices

1. Generation 0,1,2 & 3

Night vision technology has evolved significantly over the years and this sequence indicates how advanced the technology is.

 

a. Generation 0: This refers to image intensifiers that amplify ambient light in order to produce a visible picture, which makes them unsuitable for low-light conditions such as night use.

 

b. Generation 1: The devices used in these generation systems possess improved sensitivity and stability when compared to GEN 0 but the image itself does not have high resolution.

 

c. Generation 2: In these devices, the image is amplified to a much higher degree and has significantly improved detail as well as better color fidelity compared to GEN 1 devices.

 

d. Generation 3: This generation of night-vision devices offers a significant improvement over GEN 2 with features such as an automatic brightness control and an active illumination system.

 

2. Uncooled vs Cryogenically Cooled

Night vision devices come with either uncooled or cryogenically cooled infrared sensors:

 

a. Uncooled: The infrared sensor in these devices is not cooled to a very low temperature and hence the device itself is much lighter when compared to its cryogenically cooled counterpart.

 

b. Cryogenically Cooled: This type of night vision device has sensors that are cooled to extremely low temperatures using liquid nitrogen in order to enhance the resolution and clarity of the image created by these devices.

 

3. Night Vision Magnification Levels

When using night vision goggles, it is important to keep in mind that higher magnification levels tend to reduce the field of view that a device offers, which is why it’s important to pick a magnification level that suits your needs.

 

a. Low Light Level: These devices offer 3-4x magnification as well as a wide field of view. They are best used for short-range observation and monitoring activities.

 

b. Medium Light Level: With a magnification level of 5-7x, these night vision devices can be used for observing activities at medium ranges and carry out operations such as driving and landing.

 

c. High Light Level: This level offers 8-10x magnification and is best suited to long-range observation, which makes it perfect for outdoor use.

 

How to Use Night Vision Devices

Before anything else, getting familiar with the controls is very crucial. It’s important for users of night vision devices to become familiar with controls such as image brightness and contrast, manual gain (amplification), focus controls, and diopter adjustment.

 

There are several steps you should follow when using night vision devices for surveillance or reconnaissance missions:

 

Step 1: Place the device in front of your eyes and turn it on. Adjust the eyepiece so that everything is clearly visible. The image you’re viewing may be blurry at first, but it will likely become clearer as you continue using the equipment.

 

Step 2: Focus on an object that’s around 50 yards away. Do this by adjusting the focus ring until the image is sharp and clear. Once you have a clear image, adjust your position to get a better view of what’s happening in front of you.

 

Step 3: Continue focusing on that object until it becomes clear. If you have a handheld device, point the camera towards the target and record footage of what’s happening. In most cases, it’s best to be as inconspicuous as possible when performing reconnaissance missions.

 

When you’re finished using your night vision equipment, remove your eye from the eyepiece and turn it off.

When night vision is used as an optical system, it can create a clearer image so that you can see everything at night time.