The document provides a comprehensive overview of night vision technology, detailing its history, biological and technical aspects, and various applications, especially in military and automotive contexts. It explains the mechanisms of image intensification, active illumination, and thermal imaging, and outlines different night vision devices like goggles, cameras, and scopes. The technology is highlighted as essential for low-light visibility and has numerous modern applications ranging from security to wildlife observation.

1. NIGHT VISION TECHNOLOGY
(A MIRACLE !)
BY –
SACHIN
2315639
THE BULLETS DON’T CARE HOW DARK IT IS

2. CONTENTS
Introduction to Night Vision
History
Biological Night Vision
Technical Night Vision categories
Night Vision Devices
Applications of Night Vision technology
Night Vision system in cars
Conclusion

3. INTRODUCTION
Night Vision : Ability to see in low light conditions.
Humans have poor night vision compared to many
animals.
Earlier flares and spotlights were used for
operations at night.

4. HISTORY
Originally developed for military use.
In 1929 Kalman Tihanyi(Hungarian
Physicist) invented night vision for
anti - aircraft defense in UK.
First military night vision device
introduced by Germany in 1939.
Used during world war 2 for the first
time.
Came into wide use during Vietnam
war.

5. HOW FAR CAN WE SEE?
 Recognition Range : Approx. 200m.
o On a moonless cloudy night we can tell the
difference between a male and a female or a dog
and a deer standing at about 200m.
 Detection Range : Depends on two variables
o Size of the object
o Lighting conditions

6. TAPETUM LUCIDUM
(BIOLOGICAL/NATURAL NIGHT VISION)
 A layer of tissue in the eye of
many vertebrates.
 Lies immediately behind the
retina.
 Reflects visible light back to
retina.
 Reason behind glowing eyes
of some animals in dark.

7. TECHNICAL NIGHT VISION CATEGORIES
 Image Intensification
 Active Illumination
 Thermal Imaging

8. IMAGE INTENSIFICATION
INTRODUCTION
Also called light amplification.
Device used - image intensifier
(vacuum tube based device).
Can generate an image from a very
small no. of photons.
Much like a CRT television.
Photocathode instead of colour guns
does the emitting.

9. HOW IMAGE INTENSIFIER WORKS?
 Available photons strikes photo cathode plate.
 Photo cathode emits electrons.
 These electrons strike a microchannel plate.
 For every electron, MCP emits thousands of
electrons.
 Multiplied electrons strikes on phosphor screen.
 Photons coming from phosphor screen are more,
so the image is more clearly visible.

10. HOW IMAGE INTENSIFIER WORKS?(CONTD…)

12. PHOTO CATHODE
 Negatively charged electrode.
 Coated with photosensitive compound(mainly
alkali metals).
 Emits electron when struck by photons due to
photoelectric effect.
 Some photo cathode materials are :
o GaAs (Gallium Arsenide)
o InGaAs (Indium Gallium Arsenide)
o Cs-Te (Caesium-Telluride)
o Cs-I (Caesium-Iodide)

13. TYPES OF PHOTOCATHODE
Three types : Transmission, Reflective & Variation.
Transmission type is a coating on glass.
Light strikes on one surface & electrons exit from
the other.
Reflective type is formed on opaque metal electrode
base.
Light enters & electrons exit from same side.
Variation – Also called double reflection type.
Metal base is mirror like.

14. PHOTOELECTRIC EFFECT
 Emission of photo electrons
when light shines on a
material.
 Photon strikes the material.
 Electron absorbs energy of
photon.
 Acquire more energy than
work function(electron
binding energy).
 Some energy liberates
electron & rest contributes
to K.E.

15. MICROCHANNEL PLATE
 Slab made of highly resistive
material.
 Thickness – 2mm.
 Regular array of tiny tubes or
slots called micro channels.
 Micro channel Dia. -
10µm.(6µm. in high resolution
MCPs).
 Parallel to each other &
spaced apart by 15µm.

16. WHY GREEN?
Most of the night vision
devices available in market
based on Image
Intensification shows green
image.
Because the phosphor is
green in colour.
Good for human eye to pick
up detail.

17. ADVANTAGES OF IMAGE
INTENSIFICATION
Excellent low light level
sensitivity
High resolution
Low cost compared to others
Ability to identify people

18. DISADVANTAGES OF IMAGE
INTENSIFICATION
Possibility of damage when
observing bright sources
under low light conditions.
Not useful when there is
essentially no light.
Lack of colour discrimination.

19. ACTIVE ILLUMINATION
 Lighting whose direction, intensity, and pattern
are controlled by commands or signals.
 Couples Image Intensification technology with an
active source of illumination.
 Risk of getting detected in military operations.
 High range of vision even in fog & smoky areas.
 Used in high speed video capturing of the vehicle
movement.

20. THERMAL IMAGING
 Works on IR radiations.
 Higher the temp., more are
the radiations.
 Detects the temp. difference
& create detailed temp.
pattern called Thermogram.
 Thermogram translated into
electric impulses.
 Processor translates these
impulses into data(diff.
colour for diff. temp.) to
display.

21. THERMAL IMAGING(CONTD…)
 Normally in Grey scale.
 Cold Objects are in black.
 Hot objects are in white.
 Some Thermal Cameras
add colour to images.
 Helps in identifying
objects at different temp.

22. THERMAL IMAGING(CONTD…)

23. THERMAL IMAGING(CONTD…)
ADVANTAGES
 No light is required.
 Produces fast, accurate &
immediate temp. measurement.
 Capable of catching moving
targets in real time.
 High range of vision even in fog
& smoke.

24. THERMAL IMAGING(CONTD…)
DISADVANTAGES
 Very expensive.
 Difficult to identify people.
 Can only detect surface
temp.
 For any survey, temp.
difference is must.

25. NIGHT VISION DEVICES
GOGGLES
Goggles are binoculars(two
eye pieces).
Mostly worn on head.
Can be handheld.
Excellent for constant
viewing such as moving
around in dark building.

26. NIGHT VISION DEVICES(CONTD…)
CAMERA
Sends the image to a
monitor for display.
Used for security
purposes.
Used for wildlife
photography.
Used in movie making.

27. NIGHT VISION DEVICES(CONTD…)
SCOPE
Normally handheld or mounted on
a weapon.
Scopes are monocular(one eye
piece).
Good when we want to get better
look of a object & then return to
normal viewing conditions.

28. APPLICATIONS
 Military
 Hunting
 Wildlife observation
 Surveillance
 Security
 Navigation
 Hidden object detection
 Entertainment

29. NIGHT VISION SYSTEM IN CARS
 Vehicle’s dark surrounding becomes visible up to a
distance of 150 m.
 Electronically processed video image is generated.
 Displayed in real time in head up display.
DISPLAY IN INSTRUMENT CLUSTER
VISIBILITY WITH NIGHT VIEW ASSISTANT
VISIBILITY WITH
LOW BEAM
HEADLAMPS

30. NIGHT VISION SYSTEM IN CARS(CONTD…)

31. CONCLUSION
It’s a critical study.
Plays vital role in modern world.
Involved with advance use of science & technology.
Advances in technology have created tremendous
opportunities for vision system.
Applicable in various fields.

32. THANK YOU