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8/2/2019 Night Vision Tech Ppt Deepika
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NIGHT VISION
TECHNOLOGY
BYTushar choudhary
TT-CS
8/2/2019 Night Vision Tech Ppt Deepika
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NIGHT VISION TECHNOLOGY
IntroductionTypes of NVT
Thermal Imaging
Image EnhancementPerformance Attributes
Technical characteristics
EquipmentsApplications
Conclusion
References
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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 rescueEvolved from bulky optical instruments
in lightweight goggles through theadvancement of image intensificationtechnology.
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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 Problems –acceleration 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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Figure illustrates Generation 1Night vision technology.
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Generation-1 (1960’s)
Uses passive infrared
Uses ambient light provided by the moonand the stars
Don’t require a source of projectedinfrared light
Don’t work well on cloudy or moonlessnights
One quarter moon operation
Uses same image-intensifier tubetechnology as Generation-0
Same problems as faced by the
Generation-0
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Figure illustrates Generation 2Night vision technology.
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Generation-2 (1970’s)
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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Generation-3 (1990’s)
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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Generation-4 (2000’s)
Known as “filmless and gated”technology
Shows significant improvement in bothhigh- and low-level light environments
No ion barrier in MCP
Responds quickly to different lightningconditions
Reduced background noise
Enhances signal to noise ratio
Images are less distorted and brighter
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Thermal imaging This 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
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Image Enhancement
It is also known as Image intensification
Relies on image intensifier tube to collectan amplify infrared and visible light
Lens captures the light which is then sentto image intensifier tube
It has photocathode that converts photonsinto electrons
When electrons pass through MCP ,moreelectrons 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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Sensitivity (photo response)- tube’sability to detect the available light
Signal- plays a key role in night
vision’s performance
Resolution- ability to dissolve detailin the image
Performance Attributes
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Technical Characteristics
Textures, Light and Dark
Depth Perception
Fog and RainHoneycomb
Spots
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Equipments
Three categories
Scopes
Goggles
Cameras
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Scopes- monocular, handheld,better look at a specific object andthen return to normal viewing
conditions.Goggles- binocular, handheld or
worn, excellent for constantviewing
Cameras- send the image to amonitor for display or to a VCR forrecording.
Equipments
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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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Soldiers using
DARK INVADER night-vision Goggles.
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Military
Law enforcement
Hunting
Wild life observationSurveillance
Security
Navigation
Hidden-object detection
Entertainment
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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