NIGHT VISION

TECHHNOLOGY

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Night Vision Technology

Night Vision Technology is used to view objects in darkness.

Night vision Technology by literally allows one to see in the dark.

This technique is mostly used by night vision devices.

NVD basically works on IR spectrum. The light with shorter wavelength have higher

energy.

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NEAR INFRARED MID INFRARAED THERMAL INFRARAED

The IR spectrum is classified into three.

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IR emission occurs when some changes occurs in the atomic level of objects.

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If energy is applied to an atom the electron in it jumps to higher energy level.

As the electron trends to return to its ground state, it release its energy as photons.

This photon has specific wavelength depends on its energy level.

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Night vision can work in two ways.

Thermal Imaging

Image Enhancement

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Thermal Imaging

The thermal imaging technology operates by capturing the upper portion of IR light spectrum. The infrared spectrum is emitted as heat by objects instead of simply reflected as light. The warm objects emit more IR light than cooler objects.

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WORKING

A special lens focuses the IR light emitted by all of the objects in view.

The focused light is scanned by a phased array of IR detected elements.

This scanning create a very detailed temperature pattern called thermogram.

The thermogram created by the detector elements is translated into electric impulses.

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The electric impulses are then send to a signal processing unit which translates them into data for the display.

The signal processing unit send the information to the display. It’s colour depends on the intensity of IR emission.

The combination of all the impulses from all the elements create the image.

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IMAGE ENHANCEMENT

Image enhancement systems are normally called NVD’s. NVD’s rely on a special tube called an image intensifier tube to collect and amplify IR and visible light.

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Working An objective lens captures near-IR light.

The gathered light is send to the image-intensifier tube. The power supply for this tube receives power from two N-cell or AA battery.

The image intensifier tube has a photo cathode, which is used to convert the photons into electrons.

When the electron pass through the tube, similar electrons are released from atoms and it multiplies in number through micro channel plate(MCP).

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Working An objective lens captures near-IR light.

The gathered light is send to the image-intensifier tube. The power supply for this tube receives power from two N-cell or AA battery.

The image intensifier tube has a photo cathode, which is used to convert the photons into electrons.

When the electron pass through the tube, similar electrons are released from atoms and it multiplies in number through micro channel plate(MCP).

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An MCP is a glass disc that has various microscopic holes and has metal electrodes on both sides.

When a electron from the photo cathode hit the first electrode of MCP they get accelerated.

As electron pass through the micro channels they release other electrons using a process called Cascaded secondary emission.

The new electron collide with atoms creating a chain reaction result in rapid increase of electron.

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An MCP is a glass disc that has various microscopic holes and has metal electrodes on both sides.

When a electron from the photo cathode hit the first electrode of MCP they get accelerated.

As electron pass through the micro channels they release other electrons using a process called Cascaded secondary emission.

The new electron collide with atoms creating a chain reaction result in rapid increase of electron.

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An MCP is a glass disc that has various microscopic holes and has metal electrodes on both sides.

When a electron from the photo cathode hit the first electrode of MCP they get accelerated.

As electron pass through the micro channels they release other electrons using a process called Cascaded secondary emission.

The new electron collide with atoms creating a chain reaction result in rapid increase of electron.

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The micro channels are created at a slight angle to encourage electron collision.

At last the electron hit a screen coated with phosphorus. This cause phosphorus to reach exited state and release photons.

This photons create green image which characterize night vision.

The viewed image can be magnified and focused through occular lens.

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CHARACTERISTICS

Textures, light and dark The objects that are clearly

visible on day appear dark and vice versa through night vision unit.

Fog and Rain Fog and rain reflect more light

towards the night vision unit and this may degrade its performance.

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Honey comb

This is a faint hexagonal pattern witch is the result of the manufacturing process.

Black spots A few is a inherent

characteristics of night vision technology which remain constant and will not increase in size or number.

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EQUIPMENTS

Night vision Equipments can be classified into three categories.

Scope

Goggle

Cameras

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Scopes

Scopes are monocular can be handheld or mounted on a weapon.

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Goggles

Goggles are binocular can be handheld or worn on the head.

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Cameras

Cameras with night vision technology can send the images to a monitor or VCR for display or recording.

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APPLICATIONS

Military Law Enforcement Hunting Wild life observation Surveillance Security Navigation Hidden object detection Entertainment

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ADVANTAGES

Night vision devices are compact in size and is easily portable.

It is widely used in military purposes so it is reliable.

It’s working is very simple so it is easy to use.

It is designed for a long life.

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DISADVANTAGES

Night vision devices is very costly.

It cannot properly be used in rain and fog as it degrade its performance.

Poor quality images due to black spots.

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CONCLUSION

The new generation began to discover the unique world that can be found after darkness falls. Thus in the modern times night vision technology become a part of our daily life. Night vision devices can be useful to you – just be sure to get the right type of your needs.