NIGHT VISION TECHNOLOGY A SEMINAR REPORT

[seminar class]

Presented By:
Vrishali Atrey

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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.
Types of night vision
 Categorized by generations
Generation-1
Generation-2
Generation-3
Generation-4
 Mainly divided into 2 categories
Thermal imaging
Image Enhancement
Generation-1 (1960’s)
 Uses passive infrared
 Uses ambient light provided by the moon and the stars
 Don’t require a source of projected infrared light
 Don’t work well on cloudy or moonless nights
 One quarter moon operation
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.
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
Generation-4 (2000’s)
 Known as “film less 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
• Technologies used in night vision
• Night vision can work in two very different ways, depending on the technology used :
1. Image Enhancement.
2. Thermal Imaging.
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 àelectric pulsesà display data
• The basic components of a
“Thermal-imaging system”
• Thermal imaging
Thermal imaging devices
 Two types:
1. Uncooled.
2. Cryogenically cooled.
 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
Image Enhancement
• Image Enhancement Technology used in NVD
Technical Characteristics
 Textures, Light and Dark
 Depth Perception
 Fog and Rain
 Honeycomb
 Spots
Equipments
Three categories
 Scopes
 Goggles
 Cameras
 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.
• Soldiers using
DARK INVADER night-vision Goggles
Applications
 Military
 Law enforcement
 Hunting
 Wild life observation
 Surveillance
 Security
 Navigation
 Hidden-object detection
 Entertainment
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.