NIGHT VISION TECHNOLOGY A SEMINAR REPORT

[seminar class]

SUBMITTED BY :
NEENA M. ROCHE

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Introduction
 NVT allows us to see in the dark
 Originally developed for military use
 Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology.
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
Generation-0
 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
Generation-1 (1960’s)
 Uses passive infrared
 Uses ambient light provided by the moon and the stars
 Light amplification is around 1000x
 Don’t require a source of projected infrared light
 Don’t 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
Generation-2 (1970’s)
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 micro channel plate(MCP) to the image-intensifier tube
The images are less distorted and brighter
Light amplification is around 20000x
Generation-3 (1990’s)
 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
 Light amplification is around 30000 to 50000x
Generation-4 (2000’s)
 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
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
Thermal imaging detectors
 Two types:
 Uncooled :The infrared detector elements are contained in a unit that operates at room temperature.
 Cryogenically cooled: These are the systems sealed inside a container that cools below 32F.
 Great for detecting people or working in near-absolute darkness
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
Performance Attributes
Sensitivity (photo response)- tube’s ability to detect the available light
Signal- plays a key role in night vision’s performance
Resolution- ability to dissolve detail in the image
Technical Characteristics
Textures, Light and Dark
Depth Perception
Fog and Rain
Honeycomb
Spots
Equipments
Three categories:
Scopes
Goggles
Cameras