A SEMINAR ONNIGHT VISION TECHNOLOGY

Sumitted by: SARJU BHATNAGAR

TABLE OF CONTENTCONTENTS PAGE NO.

NIGHT VISSION TECHNOLOGY 2

TYPES OF NIGHT VISION TECH. 5THERMAL IMAGING 6WORKING 7

IMAGE ENHANCEMENT 10WORKING

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BLACK SPOTS 16

EQUIPMENTS 20

SCOP 22

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LIST OF FIGURESLevel of orbit

1.1Thermal Imaging

1.2Multi channel plate

1.3fig. of image enhancement

1.4Black spots

1.5

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

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Figure;1.1

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 ImagingThe 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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Figure ;1.29

Fig; 1.310

IMAGE ENHANCEMENTImage 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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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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Fig; 1.3

It is quite easy to see everything during the day...

But at night, we can see very little

Night Vision device lets us see again

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Fig;1.4

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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Fig:1.5

Fig; 1.6

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Why do NVD devices always show Why do NVD devices always show images in hues of green?images in hues of green?

The image is green because the phosphor is green in colour that is good for human eye to pick up detail

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B)The actual first inventors of NVD were little green aliens

A) The original designers of NVD had an obsession with the color.

C) NVD use green because it allows for more defined images.

C The screen was purposefully colored green due to the scientific fact that the human eye can differentiate more shades of green that any other color.

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EQUIPMENTSNight vision Equipments can be

classified into three categories. Scope

Goggle

Cameras

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ScopesScopes are monocular can be handheld

or mounted on a weapon.

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GogglesGoggles are binocular can be handheld

or worn on the head.

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CamerasCameras with night vision technology

can send the images to a monitor or VCR for display or recording.

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Far infrared in Operating with front mounted camera

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What’s Next ?? Future Scope Vision System + GPS Navigation = Driverless vehicle

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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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CONCLUSIONThe 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.

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References

1. www.answer.com2. www. night vision.com3. www.google.com4. www.wikipedia.com

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THANK YOUTHANK YOU

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