Detailed information

1. NIGHT VISION
TECHNOLOGY
NIGHT VISION
TECHNOLOGY
Shaista jan
190466

2. INTRODUCTION
• The word ‘Night vision’ itself means the ability
to see in low light conditions.
• Humans have poor night vision compared to
many other animals.

3. (Contd...)
• So we all might have a question in our mind that
is this really possible to see in the dark night?
• The answer is……..YES, we can see in the
dark night using the proper equipment made by
using this technology.
•We can see a person standing over 183m away in
the dark night.

4. HISTORY
•Pre 1940’s: Flares and spot lights were used for
operations at night.
•Due to the nature of these early night vision
devices (NVD), they gave away tactical positions.
•Military scientists began to think of ways to
improve night vision to gain a strategic advantage

5. •The first night vision devices (NVD) were
created duringWorld war-II.
•Functioned by placing an infrared filter over a
searchlight.
•Fighters would use special binoculars to see
using the light from the searchlights.
EARLY DEVELOPMENT

6. A tank from
WorldWar II
equipped
with a
search light
used for
night
combat.

7. •The night vision is possible because of two
approaches:
(1) Sufficient spectral range
(2) Sufficient intensity range
•Two technologies are used for night vision:
(1)Thermal Imaging
(2)Image Enhancement
HOW DOES IT WORK?

8. (Contd…)
•Infrared light is used to visualize the things in
the dark.
•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.

10. (Contd…)
Infrared light can be split into three categories:
Near-infrared (near-IR) –
Closest to visible light, near-IR has wavelengths
that range 0.7 to 1.3 micron.
•Mid-infrared (mid-IR) –
Mid-IR has wavelengths ranging from
1.3 to 3 microns.
Both near-IR and mid-IR are used by a variety of
electronic devices, including remote controls.

11. (Contd…)
•Thermal-infrared (thermal-IR) –
Occupying the largest part of the infrared
spectrum, thermal-IR has wavelengths
ranging from 3 microns to over 30 microns.

12. THERMAL IMAGING
•A special lens focuses the infrared light emitted
by all of the objects in view.
•The focused light is scanned by a phased array of
infrared-detector elements.
•The detector elements create a very detailed
temperature pattern called a thermogram.
•It only takes about one-thirtieth of a second for the
detector array to obtain the temperature
information to make the thermogram.

13. (Contd…)

14. (Contd…)
•This information is obtained from several
thousand points in the field of view of the detector
array.
•The impulses are sent to a signal-processing
unit, a circuit board with a dedicated chip that
translates the information from the elements into
data for the display.
•The thermogram created by the detector
elements is translated into electric impulses.

15. (Contd…)
•The signal-processing unit sends the
information to the display, where it appears as
various colors depending on the intensity of
the infrared emission.
•The combination of all the impulses from all of
the elements creates the image.

16. In day light In dark night
Using thermal imaging

17. IMAGE ENHANCEMENT

18. • An image-intensifier tube is used to collect and
amplify infrared and visible light.
•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.
•The image-intensifier tube has a
photocathode, which is used to convert the
(Contd…)

19. (Contd…)
•A Microscopic plate(MCP) is a tiny glass disk that
has millions of microscopic holes in it.
•The MCP is contained in a vacuum and has metal
electrodes on either side of the disc.
•When the electrons from the photo cathode hit the
first electrode of the MCP, they are accelerated into
the glass micro-channels by the 5,000-V bursts being
sent between the electrode pair.

20. •As electrons pass through the micro channels, they
cause thousands of other electrons to be released in
each channel using a process called cascaded
secondary emission.
•At the end of the image-intensifier tube, the
electrons hit a screen coated with phosphors.
•These electrons maintain their position in relation
to the channel they passed through, which provides
a perfect image since the electrons stay in the same
alignment as the original photons.
(Contd..)

21. (Contd…)
•The energy of the electrons causes the phosphors
to reach an excited state and release photons.
•These photons create the image on the screen.
•The green phosphor image is viewed through
another lens, called the ocular lens, which allows
you to magnify and focus the image.
•The NVD may be connected to a monitor to
display the image.

22. GENERATIONS
• NVDs have been around for more than 50 years.
They are categorized by generation.
• Each substantial change in NVD technology
establishes a new generation.

23. (Contd…)
GENERATION- 0
• Created by US Army.
• Uses active infrared.
• A projection unit called IR illuminator is attached
with NVD.
• Use anode in conjunction with cathode to accelerate
the electrons.
• Problems : acceleration causes distortion of image
and reduction of the life of the tube.
• Duplicated by the hostile nations.

24. (Contd…)
GENERATION- 1
• Uses passive infrared.
• Uses ambient light provided by the moon and the
stars.
• Doesn’t require a source of projected infrared light.
• Doesn’t work well on cloudy or moonless nights.
• Uses same image-intensifier tube technology as
Generation-0.
• Same problems as faced by the Generation-0.

25. (Contd…)
GENERATION- 2
• 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.

26. (Contd…)
GENERATION- 3
• Currently used by the US Army.
• Better resolution and sensitivity.
• Photocathode is made up of GalliumArsenide-
efficient of converting photons to electrons.
• MCP is coated with an ion barrier.
•Tube life is increased

27. (Contd…)
GENERATION- 4
• Known as filmless and gated technology.
• Shows significant improvement in both high- and
low-level light environments.
• No ion barrier in MCP.
• Reduced background noise.
• Enhances signal to noise ratio.
• Images are less distorted and brighter.

28. NIGHTVISION DEVICES
It can be splitted in three broad categories:
I. Scopes
II. Goggles
III. Cameras

29. (Contd…)
SCOPES

30. (Contd…)
•Normally handheld or mounted on a
weapon, scopes are monocular (one eye-piece).
• Can not be worn like goggles.
• It is good for when you want to get a better look
at a specific object and then return to normal
viewing conditions.

31. (Contd…)
GOGGLES

32. •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.
• Goggles are excellent for constant viewing, such
as moving around in a dark building.
(Contd…)

33. (Contd…)
CAMERAS

34. (Contd…)
•Cameras with night-vision technology can send
the image to a monitor for display or to aVCR for
recording.
•When night-vision capability is desired in a
permanent location, such as on a building.

35. APPLICATIONS
•Military
•Hunting
•Wildlife observation
•Surveillance
•Security
•Navigation
•Hidden-object detection
•Entertainment

36. BMW's NightVision
with Pedestrian
Detection system
allows drivers to see
what (or who) is down
the road -- even on the
darkest nights.
AUTOMOBILE
(Contd…)

37. • Dr. Prabhat Ranjan from DA-IICT has used a
camera based on Infrared flash in his research on
‘Sensor Networks in wildlife’.
(Contd…)

38. REFERENCES
•http://en.wikipedia.org/wiki/Night_vision
•http://electronics.howstuffworks.com
•http://carl.sandiego.edu

39. THANK YOU