Night vision

Post on 28-Jan-2015

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NIGHT VISION TECHNOLOGY

Presented By:- Abiresh Mishra

1011019118ICE-’B’

Guided By:- Mr. Abhisek ParidaAssistant ProfessorDepartment of ICE

Introduction

Night vision is used to locate an object which is 200 yards away even in moonless, cloudy night

Night vision can work into two different ways, depending on the technology used

They are image enhancement and thermal imaging. Image enhancement works by collecting lower portion of infrared light spectrum

Thermal imaging operates by capturing the upper portion of the infrared light spectrum

TYPES OF NIGHT VISION

It is broadly classified into two types Biological Night VisionMolecules in the rods of the eye undergo a change in shape as light.

Molecules in the human rods is insensitive to the light.

Technical Night VisionImage intensifier Thermal imaging

Technical Night Vision

Image Intensifier Night vision amplifies light to achieve better vision . A conventional lens, captures ambient light. The gathered light is sent to the image-intensifier tube. The light energy released electron from the cathode and accelerated. These electrons enter micro channel plate and bounce off and generate more

electron. Thousands of other electrons to be released in each channel. Original electrons collide with the channel , exciting atoms and causing other

electrons. New electrons collide with other atoms, creating a chain.

Technical Night Vision (cont..)

In image-intensifier tube, the electrons hit a screen. The energy of the electrons release photons and create green

image on the screen. The green phosphor image is viewed through another lens.

Technical Night Vision (cont..)

Thermal Imaging

All objects emit infrared energy as a function of their temperature. A lens focuses the infrared light. The focused light is scanned and create temperature pattern. The pattern created is translated into electric impulses. The impulses are sent to a circuit board that translates the

information into data for the display.

Technical Night Vision (cont..)

The signal-processing unit sends the information to the is play, and appears as various colors.Thermal images are black and white in nature.

NIGHT VISION DEVICES

Night vision devices are basically divided into three categories SCOPESThey are monocular normally

handheld or mounted on a weapon.GOGGLESThey are binocular and

worn on the head.CAMERAS Used for transmission or recording

of images mostly if the location is fixed.

GENERATIONS

Generation 0 The earliest (1950's) night vision products were based

on image conversion, rather than intensification.Generation 1 Vacuum Tube Technology Full Moon Operation Amplification: 1,000 Operating Life: 2,000 Hours

GENERATIONS (cont..)

Fig:- Generations1 Night visionSources: http://www.nightvision.com

GENERATIONS (cont..)

Fiber optic plates collimate incoming light before impacting a photo cathode which releases electrons, which in turn impact a phosphor screen

The excited screen emits green light into a second fiber optic plate, and the process is repeated

The complete process is repeated three times providing an overall gain of 10,000

GENERATIONS (cont..)

Generation 2First Micro channel Plate ApplicationOne-Quarter Moon OperationAmplification: 20,000Operating Life: 2,500 Hours Generation3 Improved Micro channel Plate & PhotocathodeStarlight OperationAmplification: 40,000Operating Life: 10,000 Hour

GENERATIONS (cont..)

Fig:- Generations2 Night vision deviceSources: http://www.nightvision.com

GENERATIONS (cont..)

In second-generation night visions the addition of the micro channel plate (MCP) collimated electron flow and increased the light-amplification gain Current image intensifiers incorporate their predecessor's resolution with additional light amplification

The multi alkali photo cathode is replaced with a gallium arsenide photocathode; this extends the wavelength sensitivity of the detector into the near infrared

The moon and stars provide light in these wavelengths, which boosts the effectively available light by approximately 30%, bringing the total gain of the system to around 30,000

Applications

Military Law enforcement Hunting Wildlife observation Surveillance Security Navigation Hidden-object detection Entertainment

CONCLUSIONS

Night vision devices are basically designed for utmost defensive purposes but the application within the scientific or the civilian range is often prohibited by law.

In present scenario the applications of night vision technology is very essential to combat terrorism which is a major problem being faced by mankind.

It is mainly used in military purposes as well as navigation , surveillance and targeting .

Night vision is used to locate an object which is 200 yards away even in moonless , cloudy night

References

Thank you!