Deprt. Of Electrical and Electronics Engineering
TYPES OF NIGHT VISION
NIGHT VISION DEVICES
Night vision technology allows one to see in darkness.
It is mainly developed for military surveillance.
We can see a person standing over 180 m distance in a
moonless and cloudy night.
It plays a key role in search and rescue operations.
Biological night vision:
Molecules in the rods of the eye undergo a change in shape
according to the light.
Molecules in the human rods is insensitive to the light
Technical night vision:
Night vision amplifies light to a better vision.
A convention lens will capture completely envelops the surrounding
The gathered light is sent to the image intensifier-tube.
In each channel there release thousands of electrons.
Electrons collide with each other and produce more.
The new atoms again collide and creates a chain.
These electrons after hitting a screen will produce photons and crea
a green image.
This green phosphor image is viewed through lens
In order to understand thermal imaging, it is important to
understand something about light.
Three Types of IR rays:
Closest to visible light, near – IR has wavelengths
that range from 0.7 to 1.3 microns.
Mid – IR has wavelengths ranging from 1.3 to 3 microns.
Thermal infrared the largest part of the infrared spectrum,
thermal – IR has wavelengths ranging from 3 microns to over 30
All objects emit infrared energy a function as a
function of their temperature
All objects emit infrared energy a function as a function of their
A lens will focuses the infrared light.
The focused light is scanned and create temperature pattern
The pattern is translated into electric impulses.
The impulses sent to an electrical circuit board that translates the
information into the data to display
The signal processing unit sends the information and it appears in
Generally thermal images are black and white in nature.
Night vision device can be split into three categories
They are monocular normally
handheld or mounted on a
The night vision binocular and
worn on the head
Used for transmission or
recording images mostly if the
location is fixed
In 1950’s devices based on vacuum tube technology are
The vacuum tubes are simplified to single
stage in 2nd generation.
The third generation night vision devices advanced in using small
In present generation the researches are being made to bring it
into the micro electron chips.
In present scenario night vision the applications of night vision
technology is very essential to combat terrorism which is the major
problem faced by the mankind.
After a long journey from 1950’s we have much developed night
vision technology but it is limited in use.
It will yield good results in future if we use it in every field for