Night Vision Tech Ppt Rajesh Sharma

7/31/2019 Night Vision Tech Ppt Rajesh Sharma

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NIGHT VISION

TECHNOLOGY


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NIGHT VISION TECHNOLOGY

IntroductionTypes of NVT

Thermal Imaging

Image EnhancementEquipments

Applications

ConclusionReferences


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Introduction

NVT allows us to see in the dark

Originally developed for military use

Now used for site security, surveillance

as well as search and rescueNight vision devices can work in two

different ways,depending on thetechnology used:

Thermal imaging

Image enhancement.


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Types of night vision

Categorized by generations

Each substantial change NVTestablishes a new generation

Categorized into:Generation-0

Generation-1

Generation-2Generation-3

Generation-4


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Generation-0

Created by US Army Uses active infrared A projection unit called IR illuminator

is attached

Full moon operation Use anode in conjunction with cathode

to accelerate the electrons Problemsacceleration causes

distortion of image as well asreduction of life of the tube Also, it was quickly duplicated by the

hostile nations


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Generation-1 (1960s)

Uses passive infrared

Uses ambient light provided by the moonand the stars

Dont require a source of projectedinfrared light

Dont work well on cloudy or moonlessnights

Uses same image-intensifier tubetechnology as Generation-0

Same problems as faced by theGeneration-0


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Offer improved resolution andperformance over Generation-1 devices

Considerably more reliable

Able to see in extreme low lightconditions due to the addition ofmicrochannel plate(MCP) to the image-intensifier tube

The images are less distorted andbrighter


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Currently used by the US Army

Better resolution and sensitivity

Photocathode is made up of Gallium

ArsenideMCP is coated with an ion barrier

Tube life is increased


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Known as filmless and gatedtechnology

Shows significant improvement in bothhigh- and low-level light environments

No ion barrier in MCP

Responds quickly to different lightningconditions

Reduced background noiseEnhances signal to noise ratio

Images are less distorted and brighter


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Thermal imagingThis technology operates by capturing

upper portion of the infrared lightspectrum, which is emitted as heat

Hotter objects emit more of this lightthan the cooler objects

These elements then create athermogram

Thermogram electric pulses display

data


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The basic components of aThermal-imaging system


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Thermal imaging

Thermal imaging lets you see again.

It is quite easy to see everythingduring the day...

...but at night, you can seevery little.


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Thermal imaging devices

Two types:

1. Uncooled.

2. Cryogenically cooled.

Great for detecting people or

working in near-absolutedarkness


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Image Enhancement

It is also known as Image intensificationRelies on image intensifier tube to collect

an amplify infrared and visible light Lens captures the light which is then sent

to image intensifier tube It has photocathode that converts photons

into electronsWhen electrons pass through MCP ,more

electrons are presented

This causes chain reaction where atomsare released

Electrons reach phosphor screen andphotons are released

Those phosphor create green image


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Image Enhancement


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Equipments

Three categories

Scopes

Goggles

Cameras


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DARK INVADER Multi-purpose Pocketscope

DARK INVADER Night-vision Goggles 4501


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Stealth 301 Series Day/Night Video Camera

Camcorders are a fast-growing segment of the night-vision industry.


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MilitaryLaw enforcement

Hunting

Wild life observation

Surveillance

Security

Navigation

Hidden-object detection

Applications


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Conclusions

Although the term ``night vision''currently encompasses threedistinct technologies, it is the

evolution of image intensificationtechnology that first made devicespractical and widely used.

Their success was the result ofadvancements in light amplificationand resolution techniques.


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References

http://electronics.howstuffworks.com/nightvision3.html http://www.nightvision.com/military/militaryhome.html http://www.physics.ohio-

state.edu/~wilkins/writing/Samples/shortmed/johnmedium/index.html

http://www.atncorp.com/HowNightVisionWorks http://www.morovision.com/hownightvisionworks.htm http://www.alanaecology.com/acatalog/Introduction_to_

Nightvision.html


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Night Vision Tech Ppt Rajesh Sharma

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