STUDY OF NIGHT VISION TECHNOLOGYBy: Maninder Singh NagraECE-11172032

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ABSTRACT

Night Vision Technology (NVT), going by its definition, literally allows one to see in the dark. Originally developed for military use, it has provided the United States with a strategic military advantage, the value of which can be measured in lives.

Federal and state agencies now, in routine, utilize this technology for site security, surveillance as well as for search and rescue. Night vision equipment has evolved from bulky optical instruments to lightweight goggles through the advancement of image intensification technology.

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Night Vision Technology has shaped history. Pre 1940’s: Flares and spot lights were used

for operations at night. Night Vision Technology has been used to

see in the night.

INTRODUCTION

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BASICS

■ CONCEPT OF LIGHT

Figure1: Electromagnetic Spectrum[3]

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Basics

■ CONCEPT OF ATOM

Figure 3: Showing stimulated emission[3]Figure 2: Showing Atomic Structure[2]

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Basics

GREEN HOUSE EFFECT

Figure 4: Depicting the Infrared Source[7]ROLL. NO. : 11172032

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Conclusion from Basics

All objects emit Infrared rays during Night also.

To watch at night ,there is a need to intensify the available Infrared rays.

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WORKING OF NVT

Thermal ImagingImage Enhancement

There are two ways in which NVT works:

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THERMAL IMAGING

■ SPECIFICATIONS

•Scan 30 times per sec.

•Sense temperature ranging

from -20 to 2,000 degree

Celsius.

• It shows a very minute

difference of as small as 0.1

degree Celsius from more

than 1,000ft away.

Figure 5: Process of Thermal Imaging[1]

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TYPES OF THERMAL IMAGING DEVICES

CRYOGENICALLY COOLED More susceptible to damage

from rugged use. These systems have the

elements sealed inside a container that cools them below 0 degree Celsius.

A Microbolometer is not used. Very high resolution and

sensitivity. More complex and costly. Less Reliable.

UNCOOLED Less susceptible to damage

from rugged use. These systems don’t have a

need to cool the infrared detectors.

A Microbolometer is used. Low resolution and sensitivity.

Less complex and costly. More Reliable.

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IMAGE ENHANCEMENT

■ COMPONENTS

1. Front Lens

2. Photocathode

3. Micro Channel Plate

4. High Voltage Power Supply

5. Phosphor Screen

6. Eyepiece

7. Image Intensifier

Figure 6: Internal view of IIT[5]ROLL. NO. : 11172032

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WORKING OF IMAGE INTENSIFIER TUBE (IIT)

Figure 7: Showing the working stages of IIT[5]ROLL. NO. : 11172032

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DEVELOPMENTS IN NVT

Post WWII NVT focused on the ability to see without creating additional light.

During this time period,the first “Generation” of NVT began using intensified natural lighting.

GENERATION 1 Developed in 1960's

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GENERATION 1 CONT.Military scientists created a two-stage cascade image tube.

This tube intensified the natural lighting and created a superior image for the viewer.

Figure 8: Image Intensifier Tube (Generation 1)[1]ROLL. NO. : 11172032

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GENERATION 1 CONT.

The power of Generation 1 NVD was put to the test in the Vietnam War.

Star Tron Scopes intensification tubes were as heavy as the rifles they were mounted on.

The NVD emitted a whiney noise.

They would shut down if they were exposed to a sudden burst of bright light.

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GENERATION 2 Developed in 1970's

Thermal imaging allowed NV even through low natural lighted conditions.

It also allowed NV through smoky, dusty, and foggy conditions.

These thermal imagers were expensive, so in 1973 scientists created a common module that made it less expensive, and more ideal for military use.

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GENERATION 2 CONT.

The generation 2 NVT were first put to the test by US forces in the early 1990’s during Operation Desert Storm in Kuwait.

The dark nights and harsh dusty conditions were perfect for implementing the new technology.

Figure 9: Image Intensifier Tube (Generation 2)[1]ROLL. NO. : 11172032

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CURRENT GENERATIONS

The current generations of NV Source are generations 3 and 4.Generation 3 is much like generation 2 except for the fact that

it has a substantially longer life, as well as more defined images.

Generation 4 has less noise than generation 3, however it has shorter life.

Improvements o MCP & Photocathode o Starlight Operation o Amplification: 40,000 o Operating Life: 10,000 Hour

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NIGHT VISION TECHNOLOGY COMPARISON

Table 1: Depicting the characteristics of NVT Generations[7]ROLL. NO. : 11172032

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APPLICATIONS

Military

Law enforcement

Hunting

Wildlife observation

Surveillance

Security

Navigation

Hidden-object detection

Entertainment

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DISADVANTAGES OF NVT [6]

During utter darkness, IITs are uncapable to detect any object.

Thermal goggles cannot detect "cold" objects.

 200 chemical substances are needed in order to make night vision

goggles work effectively.

Thermal imaging cannot see through plates of glass.

Quality cameras often have a high price range .

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FUTURE ASPECTS

The Army is pushing NVT into the digital realm. Future NV goggles are being designed not just to see better at night but also to allow soldiers to share images of what they see with other soldiers who may be miles away.

Technologists are working to meet the challenges of the Army, which includes their requirements for power, size and weight.

The fusion of both technologies (Thermal Imaging and Image Enhancement ) would result in night-vision goggles that merge the strengths of image intensification.

The combination of the two systems into a single optical device resulted in what the Army calls an “enhanced night vision goggle,” or ENVG.

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References

[1]http://www.nightvisionexperts.com

[2] http://www.maic.jmu.edu

[3] http://electrooptic.com

[4] http://www.jagerpro.com

[5] http://www.nationaldefensemagazine.org

[6] http://www.parxy.com

[7] http://www.wikipedia.org

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QUESTIONS

?

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