Night vision technologies allow humans to see in low light conditions similarly to many animals. There are two main types of night vision cameras: image intensification and thermal imaging. Image intensification uses lenses and a photocathode to amplify available light, displaying the image in green. Thermal imaging detects infrared radiation emitted from warm objects and does not require visible light. Both methods have advantages and disadvantages for military, security, and other applications.

1. Science behind Night Vision
Camera

2. Introduction:
• Night Vision is the ability to see in low light conditions. Whether by
biological or technological.
• Humans have poor night vision compare to many animals because the
human eye lacks a tapetum lucidum.
• Now there are so many technologies which makes humans to see in
night time.

3. How animals see in Dark:
• Humans are bult for living in day time and sleeping in the dark.
• The Retina has cells called cones and rods.
• We have 20 times more rods than cones.(120M rods and 6M cones)
• So we can not see in dark but animals have more cones than us
• Animals also have tapetum lucidum in their eyes. So they can see in
dark

4. Whats makes humans enable to view objects:
• When a light projects on any object reflects the light. this reflected
light by the object enables humans to view the object.
• With this humans are able to distinguish the objecs from others
with respect to it's properties like colour,size,shape,etc.,

5. How it works:
• There are mainly two types of night vision technologies
They are :- 1.Image intensification(low light imaging)
2.Thermal imaging

6. 1.Image intensification(low light imaging):
• Today the most popular and well known method for performing night
vision is based on the use of image intensifiers
• In this image is in green colour because usage of phosphorus
• There are 3 lenses in the intensifier
• An objective lens focuses available light on the photocathode of an
image intensifier
• The light energy causes electrons to be released from cathode which
are accelerated by an electric field to increase their speed
• These electrons will hit phosphorus screen, the energy of electrons
makes the phosphorus glow

7. • A green phosphor is used in this applications because humans
eyes can differentiate more shades of green than any colour

8. Advantages:
• Excellent low light level sensitivity
• high resolution
• low power and cost
• ability to identify people
Disdvantages:
• this meyhod is not useful when there is essentially no
light
• Possibilty of blooming and damaging when observing
bright sourses under low light conditions

9. Thermal Imaging:
• This night vision method do not require any ambient light at all
• They operate on the principle that all objects emit infrared energy as
a function of thier temperature
• in general the hotter an object is the more radiation it emits
• The thermal imager is a product that collects the infrared radiation
from objects in the scene and creates an electronic image
• in addition they are also able to penetrate obstracts such as smoke,
fogg and haze

10. • There are two types of thermal imageing detectors. cooled and Uncooled
• Cooled IR detector camera require cryogenic cooling and uncooled IR
detecor camera are normally either temperature stabilised or entirely
unstabilised

11. Advantages:
• Highest possible thermal sensitivity
• Ability detect people and vehicle at great distances
• Not effected by bright light sources
• Able to perform high speed IR imaging
Disdvantages:
• Expensive to purchase and to opperate
• limited cooler operating life time
• Bulky

12. • These night visions technologies are using by our army to find
enemies in boarders and wars
• It's also used in CC TV's
• Hunting and wild life observation
• Now these are also used in cars for navigation
USES:

13. THANK YOU