NIGHT VISION TECHNOLOGY

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NIGHT VISION TECHNOLOGY

• 
  BY
• DEEPIKA.G.D
• 
  1DB05IS015
• 
  DBIT

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NIGHT VISION TECHNOLOGY

• Introduction
• Types of NVT
• Thermal Imaging
• Image Enhancement
• Performance Attributes
• Technical characteristics
• Equipments
• Applications
• 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 rescue
• Evolved from bulky optical instruments in
  lightweight goggles through the advancement of
  image intensification technology.

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Types of night vision

• Categorized by generations
• Each substantial change NVT establishes a new
  generation
• Categorized into
• Generation-0
• Generation-1
• Generation-2
• Generation-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 as reduction of life of the tube
• Also, it was quickly duplicated by the hostile
  nations

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Figure illustrates Generation 1 Night vision
technology.
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Generation-1 (1960s)

• Uses passive infrared
• Uses ambient light provided by the moon and the
  stars
• Dont require a source of projected infrared
  light
• Dont work well on cloudy or moonless nights
• One quarter moon operation
• Uses same image-intensifier tube technology as
  Generation-0
• Same problems as faced by the Generation-0

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Figure illustrates Generation 2 Night vision
technology.
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Generation-2 (1970s)

• Offer improved resolution and performance over
  Generation-1 devices
• Considerably more reliable
• Able to see in extreme low light conditions due
  to the addition of microchannel plate(MCP) to the
  image-intensifier tube
• The images are less distorted and brighter

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Generation-3 (1990s)

• Currently used by the US Army
• Better resolution and sensitivity
• Photocathode is made up of Gallium Arsenide
• MCP is coated with an ion barrier
• Tube life is increased

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Generation-4 (2000s)

• Known as filmless and gated technology
• Shows significant improvement in both high- and
  low-level light environments
• No ion barrier in MCP
• Responds quickly to different lightning
  conditions
• 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 light spectrum, which is
  emitted as heat
• Hotter objects emit more of this light than the
  cooler objects
• These elements then create a thermogram
• Thermogram ?electric pulses? display data

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The basic components of a Thermal-imaging system
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Thermal imaging
It is quite easy to see everything during the
day...
...but at night, you can see very little.
Thermal
imaging lets you see again.
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Thermal imaging devices

• Two types
• 1. Uncooled.
• 2. Cryogenically cooled.
• Great for detecting people or working in
  near-absolute darkness
  

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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 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
  electrons
• When electrons pass through MCP ,more electrons
  are presented
• This causes chain reaction where atoms are
  released
• Electrons reach phosphor screen and photons are
  released
• Those phosphor create green image

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Performance Attributes

• Sensitivity (photo response)- tubes ability to
  detect the available light
• Signal- plays a key role in night visions
  performance
• Resolution- ability to dissolve detail in the
  image

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Technical Characteristics

• Textures, Light and Dark
• Depth Perception
• Fog and Rain
• Honeycomb
• Spots

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Equipments

• Three categories
• Scopes
• Goggles
• Cameras

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Equipments

• Scopes- monocular, handheld, better look at a
  specific object and then return to normal viewing
  conditions.
• Goggles- binocular, handheld or worn, excellent
  for constant viewing
• Cameras- send the image to a monitor for display
  or to a VCR for recording.

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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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Applications

• Military
• Law enforcement
• Hunting
• Wild life observation
• Surveillance
• Security
• Navigation
• Hidden-object detection
• Entertainment

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Conclusions

• Although the term night vision'' currently
  encompasses three distinct technologies, it is
  the evolution of image intensification technology
  that first made devices practical and widely
  used.
• Their success was the result of advancements in
  light amplification and resolution techniques.

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References

• http//electronics.howstuffworks.com/nightvision3.
  html
• http//www.nightvision.com/military/militaryhome.h
  tml
• 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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NO(W) QUERIES...?
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Thank You one and all