Night vision technology

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Night vision technology
BY
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INTRODUCTION

• It allows one to see in the dark.
• Originally developed for military use, has
  provided UNITED STATES with a strategic military
  advantage whose value can be measured in life's.
• Night vision equipment has evolved from bulky
  optical instruments in lightweight goggles
  through the advancement of image intensification
  technology.

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Two different ways

• IMAGE ENHANCEMENT This works by collecting the
  tiny amounts of light, including the lower
  portion of the infrared light spectrum, that are
  present but may be imperceptible to our eyes, and
  amplifying it to the point that we can easily
  observe the image.

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• THERMAL IMAGING This technology operates by
  capturing the upper portion of the infrared light
  spectrum, which is emitted as heat by objects
  instead of simply reflected as light. Hotter
  objects, such as warm bodies, emit more of this
  light than cooler objects like trees or
  buildings.

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• Infrared light In order to understand night
  vision, it is important to understand something
  about light.
• The amount of energy in a light wave is related
  to its wavelength Shorter wavelengths have
  higher energy. Of visible light, violet has the
  most energy, and red has the least. Just next to
  the visible light spectrum is the infrared
  spectrum.

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HOW THERMAL IMAGING WORKS
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The basic compone-nts of a thermal-imaging system
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Types of Thermal Imaging Devices

• Un-cooled
• Cryogenically cooled

It is quite easy to see
everything ...but
at night, you can see
during the day...
very little.

Thermal imaging lets you see again.
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Image Enhancement-

Image-enhancement technology is what most people
think of when you talk about night vision. In
fact, image-enhancement systems are normally
called night-vision devices (NVDs). NVDs rely on
a special tube, called an image-intensifier tube,
to collect and amplify infrared and visible light.
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How Image Enhancement Works

• A conventional lens, called the objective lens,
  captures ambient light and
• some near- infrared light.
• The gathered light is sent to the
  image-intensifier tube. In most NVDs, the power
• supply for the image-intensifier tube
  receives power from two N-Cell or two
• "AA" batteries. The tube outputs a high
  voltage, about 5,000 volts, to the image-tube
  components.
• The image-intensifier tube has a photocathode,
  which is used to convert the
• photons of light energy into electrons.
• As the electrons pass through the tube, similar
  electrons are released from atoms
• in the tube, multiplying the original number
  of electrons by a factor of thousands
• through the use of a micro channel plate
  (MCP) in the tube. An MCP is a tiny
• glass disc that has millions of microscopic
  holes micro channels in it, made using
• fiber-optic technology.

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• When the electrons from the photo cathode hit the
  first
• electrode of the MCP, they cause thousands
  of other
• electrons to be released in each channel
  using a process
• called cascaded secondary emission.
  Basically, the
• original electrons collide with the side of
  the channel,
• exciting atoms and causing other
• electrons to be released.
• An interesting fact is that the micro
• channels in the MCP are created at a
  Night-vision images are known
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  for their eerie
  green tint.
• slight angle (about a 5-degree to
• 8-degree bias) to encourage electron
• collisions and reduce both ion and
  direct-light feedback from the phosphors on the
  output side.
• These phosphors create the green image on the
  screen that
• has come to characterize night vision.

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KEY GENERATION DEVELOPMENTS

• GENERATION 1 (Developed in 1960's)
• o Vacuum Tube Technology
• o Full Moon Operation
• o Amplification 1,000
• o Operating Life 2,000 Hours
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• GENERATION 2 (Developed in 1970's)
• o First Micro channel Plate (MCP) Application
• o One-Quarter Moon Operation
• o Amplification 20,000
• o Operating Life 2,500 Hours
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• GENERATION 2 (1970s)
• o Development increased image tube bias voltage
  to improve gain.
• o Additionally, a glass faceplate was added to
  improve resolution.
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• GENERATION 3 (Developed in 1990's)
• o Improved MCP Photocathode
• o Starlight Operation

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Performance Attributes

• Sensitivity, or photo response, is the image
  tube's ability to detect available light. It is
  usually measured in uA/lm," or microamperes per
  lumen. ITT's advanced technology and processing
  enable us to give our customers products with
  outstanding sensitivity.
• Signal plays a key role in night vision
  performance. ITT's micro channel plate technology
  is unsurpassed in its ability to transfer a
  strong signal from input to output. Just as
  high-end stereo equipment gives you quality
  sound, ITT Night Vision gives you a quality
  output image without "noise.
• Resolution is the third major consideration when
  purchasing night vision. This is the ability to
  resolve detail in your image. High-quality optics
  and the latest processing methods give ITT Night
  Vision the edge.
• We are the world's leader for Gen 3 image
  intensified (amplified) night vision products for
  the U.S. military.

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Technical Characteristics of Night Vision

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

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Night-vision Equipment

• Scopes - Normally handheld or mounted
  on a weapon, scopes are monocular (one
  eye-piece).
• Goggles - While goggles can be
  handheld, they are most often
  worn on the
  head. Goggles are binocular(two eye-pieces)
  and may have a single lens or stereo lens,
  depending on the
  model.
• Cameras - Cameras with night-vision
  technology can send the image to a
  monitor for display or to a VCR
  for recording..

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characteristic of Night Vision technology

• Automatic Brightness Control (ABC)
• Auto-Gated Power Supply
• Black Spots
• Binocular
• Blooming
• Bright-Source Protection (BSP) - High-Light
  Cut-Off
• Bore sighting
• C-Mount
• COMSPEC (Commercial Specification)
• Chicken Wire
• Daylight Lens Cover
• Daylight Training Filter
• Diopter
• Distortion

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• Equivalent Background Illumination (EBI)
• Emission Point
• Eye Relief
• Field-of-View
• Figure of Merit (FOM)
• Fixed-Pattern Noise (FPN)
• Footlambert (fL)
• Gain
• Gallium Arsenide (GaAs)
• Highlight Shutoff
• Interpupillary Adjustment
• Interpupillary Distance
• IR Illuminator
• IR Laser
• I2 (Image Intensification)
• IR (Infrared)
• Ip/mm
• Lumen

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• Monocular
• Nato- Stanag
• mA/W (Milliamps per Watt)
• MCP (Microchannel Plate)
• Near-Infrared
• Photocathode
• Photocathode Sensitivity
• Resolution
• Reticle (Reticle Pattern)
• Signal-to-Noise Ratio (SNR)
• Scintillation
• Screen
• Stereoscopic Night Vision
• System Gain
• Variable Gain Control
• Weaver Mounting System
• Zeroing

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Applications

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

This soldier is using DARK invader
night vision goggles
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• Thank You