NIGHT VISION TECHNOLOGY

1. BY DEEPIKA.G.D 1DB05IS015 DBIT NIGHT VISION TECHNOLOGY

2. NIGHT VISION TECHNOLOGY • Introduction • Types of NVT • Thermal Imaging • Image Enhancement • Performance Attributes • Technical characteristics • Equipments • Applications • Conclusion • References

3. 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.

4. 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

5. 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

6. Figure illustrates Generation 1 Night vision technology.

7. 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 • Uses same image-intensifier tube technology as Generation-0 • Same problems as faced by the Generation-0

8. Figure illustrates Generation 2 Night vision technology.

9. 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 microchannel plate(MCP) to the image-intensifier tube • The images are less distorted and brighter

10. 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

11. 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

12. 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

13. The basic components of a Thermal-imaging system

14. Thermal imaging ...but at night, you can see very little. It is quite easy to see everything during the day... Thermal imaging lets you see again.

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

16. Image Enhancement

17. 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

18. 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

19. Technical Characteristics • Textures, Light and Dark • Depth Perception • Fog and Rain • Honeycomb • Spots

20. Equipments Three categories • Scopes • Goggles • Cameras

21. 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.

22. DARK INVADER Multi-purpose Pocketscope DARK INVADER Night-vision Goggles 4501

23. Stealth 301 Series Day/Night Video Camera Camcorders are a fast-growing segment of the night-vision industry.

24. Soldiers using DARK INVADER night-vision Goggles.

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

26. 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.

27. References • http://electronics.howstuffworks.com/nightvision3.html • http://www.nightvision.com/military/militaryhome.html • 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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29. Thank You one and all…