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Scope :
What makes humans enable to view
any object?
What is Night Vision?
Types of Night vision technologies.
Infrared light.
Thermal imaging.
Image enhancement.
NVDs.
Applications.
References.
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What makes humans enable to
view objects?
• When a light
projects on any
object the object
reflects the light.
This reflected light
by the object
enables humans to
view the object.
• With this humans
are able to
distinguish the
object from others,
with respect to its
properties like
colour ,size, shape,
etc.
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What's night vision technology
• "Night Vision” is that
technology that provides us
with the miracle of vision
in total darkness and the
improvement of vision in
low light environments.
• The most common
methods as described
below are
 Low-Light Imaging,
 Thermal Imaging
• Intensified SLR camera
operational schematic
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Ways of working
• Works in 2 different ways:
1.Image enhancement- This works by collecting the tiny amounts
of light including the lower portion of the infrared light
spectrum, those are present but may be imperceptible to our
eyes, and amplifying it to the point that we can easily observe
the image.( low light imaging)
2:Thermal imaging- This technology operates by capturing the
upper portion of the infrared light spectrum, which is emitted
as heat by objects instead of simply reflected as light. Hotter
objects, such as warm bodies, emit more of this light than
cooler objects like trees or buildings.
• Thermal imaging operates by capturing the upper portion of
the infrared light spectrum
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Thermal Imaging
• Different from low-light
imaging methods of night
vision (which require some
ambient light in order to
produce an image), thermal
imaging night vision
methods do not require any
ambient light at all.
• They operate on the
principle that all objects
emit infrared energy as a
function of their
temperature. In general, the
hotter an object is, the more
radiation it emits.
•
A color thermal image of dog
Black and white thermal image of
docked boat
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How thermal imaging works
thermal image works
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Low light imaging:
• Today, the most popular and well known
method of performing night vision is
based on the use of image intensifiers.
• Image intensifier tube
An electro-optical device which converts
photons to electrons, amplifies them, then
converts them back to photons so the user can
see at light levels that are normally too low.
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Image intensifiers
• How they work: This method of
night vision amplifies the
available light to achieve better
vision. An objective lens focuses
available light (photons) on the
photocathode of an image
intensifier. The light energy
causes electrons to be released
from the cathode which are
accelerated by an electric field to
increase their speed (energy
level). These electrons enter holes
in a micro channel plate and
bounce off the internal speciallycoated walls which generate more
electrons as the electrons bounce
through. This creates a denser
“cloud” of electrons representing
an intensified version of the
original image.
• Image intensifier tube
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Generations 0&1
• Generation 0 – uses
active infrared.
• This means that a
projection unit called an
IR illuminator is
attached to the NVD.
• Generation 1 – uses
passive infrared.
• Once dubbed
Starlight by the U.S.
army, these NVDs
use ambient light
provided by the moon
and stars to augment
the normal amounts
of reflected infrared in
the environment.
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Generations 2&3
• Generation – 2 –.
• The biggest gain in
generation 2 is the ability
to see in extremely low
light conditions, such as
moonless night. This
increased sensitivity is
due to the addition of the
micro channel plate to the
image-intensifier tube
• Generation – 3 – The
latest and greatest NVD
technology, generation 3
is currently used by the
U.S. military
• They have even better
resolution and sensitivity.
This is because the photo
cathode is made using
gallium arsenide, which is
very efficient in
converting photons to
electrons.
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Equipment
• Scopes - Normally handheld or
mounted on a weapon, scopes
are monocular
• Goggles - While goggles can be
handheld, they are most often worn
on the head. Goggles are binocular
• Cameras - Cameras with nightvision technology can send the
image to a monitor for display or to
a VCR for recording. When nightvision capability is desired in a
permanent location, such as on a
building or as part of the equipment
in a helicopter, cameras
.
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Applications
•
•
•
•
•
•
•
•
•
Military
Law enforcement
Hunting
Wildlife observation
Surveillance
Security
Navigation
Hidden-object detection
Entertainment
• images
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Conclusion
• Think of what happens when this night
vision technology falls into the hands of
hijackers or terrorists or rival forces ?
• Thus just like other technologies, it’s a
boon when used in a right way but poses a
curse when misled
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References
1. Unknown author, “Night Vision Devices”. Book Rags.
11/12/2008
http://bookrags.com
2. Unknown author, “Night Vision Goggles”. Global
Security. 11/10/2008
<http://www.global securities.org>
3. Unknown author, “How Night Vision Works”. How Stuff
Works. 11/11/2008
<http://electronics.howstuffworks.com>
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THANK
YOU!!!
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