Transcript NIGHT VISION TECHNOLOGY (Night Vision Device) PROJECT GUIDE MR. SACHITH RAJAGOPAL LECTURER S.O.E,CUSAT PRESENTED BY: Randhir kumar parmar CS-B.

NIGHT VISION TECHNOLOGY
(Night Vision Device)
PROJECT GUIDE
MR. SACHITH RAJAGOPAL
LECTURER
S.O.E,CUSAT
PRESENTED BY:
Randhir kumar parmar
CS-B
WHAT WE WILL COVER !
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What is night vision
Night Vision Approaches
The night vision technology
Working of night vision device
Generations
Usage
Conclusion
References
What is Night Vision ??
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Ability to see in dark environment
Whether by biological or technological means, night vision is
made possible by a combination of two approaches: sufficient
spectral range, and sufficient intensity range .
Humans have poor night vision compared to many animals, in
part because the human eye does not have a tapetum lucidum
The tapetum lucidum(Latin: "bright tapestry", plural tapeta
lucida) is a layer of tissue in the eye of many animals, that lies
immediately behind or sometimes within the retina. It reflects
visible light back through the retina, increasing the light available
to the photoreceptors. This improves vision in low-light
conditions.
Night Vision Approaches
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Spectral range :
Night-useful spectral range techniques
make the viewer sensitive to types of
light that would be invisible to a
human observer. Human vision is
confined to a small portion of the
electromagnetic spectrum called visible
light. Enhanced spectral range allows
the viewer to take advantage of nonvisible sources of electromagnetic
radiation (such as near-infrared or
ultraviolet radiation). Some animals can
see well into the infrared and/or
ultraviolet compared to humans,
enough to help them see in conditions
humans cannot.
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Intensity range :
Sufficient intensity range is simply the
ability to see with very small quantities of light. Although the
human visual system can, in theory, detect single photons
under ideal conditions, the neurological noise filters limit
sensitivity to a few tens of photons even in ideal conditions.
Many animals have better night vision than humans do,
Enhanced intensity range is achieved via technological means
through the use of an image intensifier, gain multiplication
CCD, or other very low-noise and high-sensitivity array of photo
detectors.
Night Vision Device
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A night vision device
(NVD) is an optical
instrument that allows
images to be produced in
levels of light approaching
total darkness.
They are most often used by
the military and law
enforcement agencies,
but are available to civilian
users.
The figure shows night vision
goggle
EXAMPLES :
1.
the AN/PVS-14 is a
monocular
night
vision device in use
with the US military
as well as by
civilians. It may be
mounted on the
user's head for
handsfree use with a
harness or helmet
attachment
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Another example is binoculars night
vision device.
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Binocular telescopes, or binoculars
(also known as field glasses), are two
identical or mirror-symmetrical
telescopes mounted side-by-side and
aligned to point accurately in the same
direction, allowing the viewer to use
both eyes (binocular vision) when
viewing distant objects.
3.
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Another Example is
monocular situated on
the gun. The figure
shows this type of
night vision device
Working of Night Vision devices
Night Vision
technology consists of
two major types:
 image intensification
(light amplification)
and
 Thermal
imaging(infrared).
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IMAGE
INTENSIFICATION
It is also called light amplification
 It is less expensive than thermal
 Light amplification technology takes the
small amount of light, such as moonlight or
starlight, that is in the surrounding area, and
converts the light energy (scientists call it
photons), into electrical energy (electrons)
 These electrons pass through a thin disk
that's about the size of a quarter and
contains over 10 million channels.
 As the electrons travel through and strike
the walls of the channels, thousands more
electrons are released.
 These multiplied electrons then bounce
off of a phosphor screen which converts the
electrons back into photons and lets you see
an impressive nighttime view even when it's
really dark.
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All image
intensified night
vision products on
the market today
have one thing in
common: they
produce a green
output image
THERMAL IMAGING
CONTINUED….
WORKING OF THERMAL IMAGING
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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. This
information is obtained from several thousand points in the field of view of
the detector array.
The thermogram created by the detector elements is translated into electric
impulses.
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 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.
Types Of Thermal Imaging Device
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There are two common types of thermalimaging devices:
Un –Cooled
 Cryogenically Cooled
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Un-Cooled
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This is the most common type of thermalimaging device. The infrared-detector elements
are contained in a unit that operates at room
temperature. This type of system is completely
quiet, activates immediately and has the battery
built right in.
Cryogenically Cooled
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More expensive and more susceptible to damage
from rugged use, these systems have the
elements sealed inside a container that cools
them to below 32 F (zero C). The advantage of
such a system is the incredible resolution and
sensitivity that result from cooling the elements.
Cryogenically-cooled systems can "see" a
difference as small as 0.2 F (0.1 C) from more
than 1,000 ft (300 m) away, which is enough to
tell if a person is holding a gun at that distance..
Continue……
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Unlike traditional most night-vision equipment
which uses image-enhancement technology,
thermal imaging is great for detecting people or
working in near-absolute darkness with little or
no ambient lighting (i.e. stars, moonlight, etc, )
GENERATIONS
 Generation
0
 Generation 1
 Generation 2
 Generation 3
GENERATION 0
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The first night vision devices, the M1 and M3 infrared
night sighting devices, also known as the "sniperscope"
or "snooperscope", were introduced by the US Army in
World War II, and also used in the Korean War, to
assist snipers. They were active devices, using a large
infrared light source to illuminate targets. Their image
intensifier tubes function using an anode and an S-1
photocathode, made primarily of silver, caesium and
oxygen to accelerate the electrons
GENERATION 1
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First generation passive devices, introduced during the
Vietnam War were an adaptation of earlier active Gen 0
technology, and rely on ambient light instead of an
infrared light source. Using an S-20 photocathode, their
image intensifiers produce a light amplification of
around 1000x, but are quite bulky and require
moonlight to function properly.
Examples:
AN/PVS-2
GENERATION 2
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Second generation devices featured an improved imageintensifier tube utilizing micro-channel plate (MCP) with an S-25
photocathode , resulting in a much brighter image, especially
around edges of the lens. This leads to increased illumination in
low ambient light environments, such as moonless nights. Light
amplification was around 20000x Also improved were image
resolution and reliability.
Examples:
AN/PVS-4
AN/PVS-5
SUPERGEN
GENERATION 3
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Third generation night vision systems maintain the MCP from
Gen II, but now use a photocathode made with gallium arsenide,
which further improves image resolution. In addition, the MCP
is coated with an ion barrier film for increased tube life. The light
amplification is also improved, to around 30000-50000x
Examples:
AN/PVS-7
NVS-7
AN/PVS-14
NVS-14
XD-4, autogated or not
Advantage of Gen 3 over Gen 2
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Gen 3 technology improves night operational
effectiveness for military users of night vision goggles
and other night vision devices. The filmless MCP
provides a higher signal-to-noise ratio than Gen 2,
resulting in better image quality (less scintillation) under
low-light conditions. The gated power supply further
improves image resolution under high light conditions,
and the reduced halo minimizes interference from
bright light sources. These improvements also
substantially increase the detection range of the syste
Continued……
GEN 2
GEN 3
%
Improvement
1800
1800
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Signal-to-Noise
Ratio
21.0
25
20% Higher
64
64
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1.25
0.75
40% Smaller
10,000
10,000
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Resolution(lp/mm)
Halo(mm)
Reliability(hours)
Courtesy of Matt Last
Photoresponse(µA
/Im)
Detection Range
Gen 1
SuperGen
1
Gen 2
OMNI
I and II
Gen 2
OMNI
III
Gen 2
OMNI
IV
Gen 3
Detection
Range (m)
170
270
240
290
360
430
%
Improvem
ent
over Gen
1
0%
60%
40%
70%
110%
153%
How Far Can We See ??
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There are many different variables that can effect the distance
that you we see with a Night Vision device.
First which object we want to see.
The larger the object the easier it is too see.
Second. Another variable is lighting conditions. The more
ambient light we have (starlight, moonlight, infrared light) the
better and further we will be able to see .If it is cloudy and
overcast then we typically state that we can tell the difference
between a male and a female or a dog and a deer at about 75 to
100 yards.
If there is ambient light then we can see about 500 yards.
BLACK SPOTS ON THE SCREEN
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As we look through a night
vision device we may notice
black spots on the screen. A
NVD is similar to a television
screen and attracts dust and
dirt. Typically these spots can
be cleaned.
These black spots will not
affect the performance or
reliability of the night vision
device.
USAGE
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Night vision devices were originally developed
for military use, but have since spread into other
areas, such as security and police work, rescue
outfits and various amateur uses (for example
animal watching or hunting).
Conclusion
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Through night vision device we can see the
object in dark environment.
We have seen four generation of this devices
and seen different ranges.
Initially this device was used by military but
now it also available for civilians.
References
1.WWW.WIKIPEDIA.ORG
2.EN.WIKIPEDIA.ORG/WIKI/NIGHT_VISION_DEV
ICE
3.WWW.MOROVISION.COM/HOW_THERMAL_I
MAGING_WORKS.HTM
4.EN.WIKIPEDIA.ORG/WIKI/NIGHT_VISION
Thank You
Presented by
Randhir Kumar parmar
Roll No: 67
C.S. ‘B’
S.O.E., CUSAT
Questions??