NIGHT VISION NIGHT VISION TECHNOLOGYTECHNOLOGY

(Night Vision Device) (Night Vision Device)

PROJECT GUIDE PRESENTED PROJECT GUIDE PRESENTED BY: BY:

MR. SACHITH RAJAGOPAL Randhir kumar parmar MR. SACHITH RAJAGOPAL Randhir kumar parmar

LECTURER CS-B LECTURER CS-B S.O.E,CUSAT S.O.E,CUSAT

WHAT WE WILL COVER !WHAT WE WILL COVER ! What is night vision What is night vision Night Vision ApproachesNight Vision Approaches The night vision technology The night vision technology Working of night vision device Working of night vision device GenerationsGenerations UsageUsage ConclusionConclusion ReferencesReferences

What is Night Vision ??What is Night Vision ?? Ability to see in dark environmentAbility to see in dark environment Whether by biological or technological means, night vision Whether by biological or technological means, night vision

is made possible by a combination of two approaches: is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity rangesufficient spectral range, and sufficient intensity range . .

Humans have poor night vision compared to many animals, Humans have poor night vision compared to many animals, in part because the human eye does not have a tapetum in part because the human eye does not have a tapetum lucidumlucidum

The The tapetum lucidumtapetum lucidum(Latin: "bright tapestry", plural (Latin: "bright tapestry", plural tapeta lucidatapeta lucida) is a layer of tissue in the eye of many ) is a layer of tissue in the eye of many animals, that lies immediately behind or sometimes within animals, that lies immediately behind or sometimes within the retina. It reflects visible light back through the retina, the retina. It reflects visible light back through the retina, increasing the light available to the photoreceptors. This increasing the light available to the photoreceptors. This improves vision in low-light conditions.improves vision in low-light conditions.

Night Vision ApproachesNight Vision Approaches Spectral range :Spectral range : Night-useful spectral range Night-useful spectral range

techniques make the viewer techniques make the viewer sensitive to types of light that sensitive to types of light that would be invisible to a human would be invisible to a human observer. Human vision is observer. Human vision is confined to a small portion of the confined to a small portion of the electromagnetic spectrum called electromagnetic spectrum called visible light. Enhanced spectral visible light. Enhanced spectral range allows the viewer to take range allows the viewer to take advantage of non-visible sources advantage of non-visible sources of electromagnetic radiation (such of electromagnetic radiation (such as near-infrared or ultraviolet as near-infrared or ultraviolet radiation). Some animals can see radiation). Some animals can see well into the infrared and/or well into the infrared and/or ultraviolet compared to humans, ultraviolet compared to humans, enough to help them see in enough to help them see in conditions humans cannot.conditions humans cannot.

Intensity range :Intensity range :

Sufficient intensity range Sufficient intensity range is simply the ability to see with very small is simply the ability to see with very small quantities of light. Although the human visual quantities of light. Although the human visual system can, in theory, detect single photons system can, in theory, detect single photons under ideal conditions, the neurological noise under ideal conditions, the neurological noise filters limit sensitivity to a few tens of photons filters limit sensitivity to a few tens of photons even in ideal conditions.even in ideal conditions.Many animals have better night vision than Many animals have better night vision than humans do, humans do, Enhanced intensity range is achieved via Enhanced intensity range is achieved via technological means through the use of an technological means through the use of an image intensifier, gain multiplication CCD, or image intensifier, gain multiplication CCD, or other very low-noise and high-sensitivity array other very low-noise and high-sensitivity array of photo detectors.of photo detectors.

Night Vision DeviceNight Vision Device A A night vision devicenight vision device

(NVD) is an optical (NVD) is an optical instrument that allows instrument that allows

images to be produced in images to be produced in levels of light levels of light approaching total approaching total darkness.darkness.

They are most often used They are most often used by the military and law by the military and law enforcement agencies,enforcement agencies,

but are available to but are available to civilian users.civilian users.

The figure shows night The figure shows night vision gogglevision goggle

EXAMPLEEXAMPLES :S :1. 1. the AN/PVS-14 is the AN/PVS-14 is

a monocular night a monocular night vision device in vision device in use with the US use with the US military as well as military as well as by civilians. It by civilians. It may be mounted may be mounted on the user's head on the user's head for handsfree use for handsfree use with a harness or with a harness or helmet helmet attachmentattachment

2.2. Another example is binoculars Another example is binoculars night vision device.night vision device.

Binocular telescopesBinocular telescopes, or , or binocularsbinoculars (also known as field (also known as field glasses), are two identical or glasses), are two identical or mirror-symmetricalmirror-symmetrical

telescopes mounted side-by-side telescopes mounted side-by-side and aligned to point accurately and aligned to point accurately in the same direction, allowing in the same direction, allowing the viewer to use both eyes the viewer to use both eyes (binocular vision) when viewing (binocular vision) when viewing distant objects.distant objects.

3.3.

Another Example Another Example is monocular is monocular situated on the situated on the gun. The figure gun. The figure shows this type shows this type of night vision of night vision devicedevice

Working of Night Vision Working of Night Vision devicesdevices

Night Vision Night Vision technology technology consists of two consists of two major types: major types:

image image intensification intensification (light (light amplification) and amplification) and

Thermal Thermal imaging(infrared).imaging(infrared).

IMAGE IMAGE INTENSIFICATIONINTENSIFICATION

It is also called light amplificationIt is also called light amplification It is less expensive than thermalIt is less expensive than thermal Light amplification technology takes Light amplification technology takes the small amount of light, such as the small amount of light, such as moonlight or starlight, that is in the moonlight or starlight, that is in the surrounding area, and converts the surrounding area, and converts the light energy (scientists call it photons), light energy (scientists call it photons), into electrical energy (electrons)into electrical energy (electrons) These electrons pass through a thin These electrons pass through a thin disk that's about the size of a quarter disk that's about the size of a quarter and contains over 10 million channels.and contains over 10 million channels. As the electrons travel through and As the electrons travel through and strike the walls of the channels, strike the walls of the channels, thousands more electrons are released. thousands more electrons are released. These multiplied electrons then These multiplied electrons then bounce off of a phosphor screen which bounce off of a phosphor screen which converts the electrons back into converts the electrons back into photons and lets you see an impressive photons and lets you see an impressive nighttime view even when it's really nighttime view even when it's really dark. dark.

All image All image intensified intensified night vision night vision products on the products on the market today market today have one thing have one thing in common: in common: they produce a they produce a green output green output imageimage

THERMAL THERMAL IMAGINGIMAGINGCONTINUED….CONTINUED….

WORKING OF THERMALWORKING OF THERMAL IMAGINGIMAGING

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

The focused light is scanned by a phased array of infrared-The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed detector elements. The detector elements create a very detailed temperature pattern called a thermogram. It only takes about temperature pattern called a thermogram. It only takes about one-thirtieth of a second for the detector array to obtain the one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This temperature information to make the thermogram. This information is obtained from several thousand points in the field information is obtained from several thousand points in the field of view of the detector array.of view of the detector array.

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

The impulses are sent to a signal-processing unit, a circuit board The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the with a dedicated chip that translates the information from the elements into data for the display. elements into data for the display.

The signal-processing unit sends the information to the display, The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of where it appears as various colors depending on the intensity of the infrared emission. The combination of all the impulses from the infrared emission. The combination of all the impulses from all of the elements creates the image. all of the elements creates the image.

Types Of Thermal Imaging Types Of Thermal Imaging DeviceDevice

There are two common types of There are two common types of thermal-imaging devices: thermal-imaging devices:

Un –CooledUn –Cooled Cryogenically CooledCryogenically Cooled

Un-CooledUn-Cooled

This is the most common type of This is the most common type of thermal-imaging device. The thermal-imaging device. The infrared-detector elements are infrared-detector elements are contained in a unit that operates at contained in a unit that operates at room temperature. This type of room temperature. This type of system is completely quiet, activates system is completely quiet, activates immediately and has the battery immediately and has the battery built right in.built right in.

Cryogenically CooledCryogenically Cooled

More expensive and more susceptible to More expensive and more susceptible to damage from rugged use, these systems damage from rugged use, these systems have the elements sealed inside a container have the elements sealed inside a container that cools them to below 32 F (zero C). The that cools them to below 32 F (zero C). The advantage of such a system is the incredible advantage of such a system is the incredible resolution and sensitivity that result from resolution and sensitivity that result from cooling the elements. Cryogenically-cooled cooling the elements. Cryogenically-cooled systems can "see" a difference as small as systems can "see" a difference as small as 0.2 F (0.1 C) from more than 1,000 ft (300 0.2 F (0.1 C) from more than 1,000 ft (300 m) away, which is enough to tell if a person m) away, which is enough to tell if a person is holding a gun at that distance..is holding a gun at that distance..

Continue……Continue……

Unlike traditional most night-vision Unlike traditional most night-vision equipment which uses image-equipment which uses image-enhancement technology, thermal enhancement technology, thermal imaging is great for detecting people imaging is great for detecting people or working in near-absolute or working in near-absolute darkness with little or no ambient darkness with little or no ambient lighting (i.e. stars, moonlight, etc, ) lighting (i.e. stars, moonlight, etc, )

GENERATIONSGENERATIONS

Generation 0Generation 0 Generation 1Generation 1 Generation 2Generation 2 Generation 3Generation 3

GENERATION 0 GENERATION 0

The first night vision devices, the M1 and M3 The first night vision devices, the M1 and M3 infrared night sighting devices, also known as infrared night sighting devices, also known as the "sniperscope" or "snooperscope", were the "sniperscope" or "snooperscope", were introduced by the US Army in World War II, introduced by the US Army in World War II, and also used in the Korean War, to assist and also used in the Korean War, to assist snipers. They were active devices, using a snipers. They were active devices, using a large infrared light source to illuminate large infrared light source to illuminate targets. Their image intensifier tubes function targets. Their image intensifier tubes function using an anode and an S-1 photocathode, using an anode and an S-1 photocathode, made primarily of silver, caesium and oxygen made primarily of silver, caesium and oxygen to accelerate the electronsto accelerate the electrons

GENERATION 1GENERATION 1

First generation passive devices, introduced First generation passive devices, introduced during the Vietnam War were an adaptation during the Vietnam War were an adaptation of earlier active Gen 0 technology, and rely of earlier active Gen 0 technology, and rely on ambient light instead of an infrared light on ambient light instead of an infrared light source. Using an S-20 photocathode, their source. Using an S-20 photocathode, their image intensifiers produce a light image intensifiers produce a light amplification of around 1000x, but are quite amplification of around 1000x, but are quite bulky and require moonlight to function bulky and require moonlight to function properly.properly.

Examples:Examples: AN/PVS-2AN/PVS-2

GENERATION 2GENERATION 2 Second generation devices featured an improved Second generation devices featured an improved

image-intensifier tube utilizing micro-channel plate image-intensifier tube utilizing micro-channel plate (MCP)(MCP) with an S-25 photocathodewith an S-25 photocathode , resulting in a , resulting in a much brighter image, especially around edges of much brighter image, especially around edges of the lens. This leads to increased illumination in low the lens. This leads to increased illumination in low ambient light environments, such as moonless ambient light environments, such as moonless nights. Light amplification was around 20000x Also nights. Light amplification was around 20000x Also improved were image resolution and reliability.improved were image resolution and reliability.

Examples:Examples: AN/PVS-4AN/PVS-4 AN/PVS-5AN/PVS-5 SUPERGENSUPERGEN

GENERATION 3GENERATION 3 Third generation night vision systems maintain the Third generation night vision systems maintain the

MCP from Gen II, but now use a photocathode made MCP from Gen II, but now use a photocathode made with gallium arsenide, which further improves image with gallium arsenide, which further improves image resolution. In addition, the MCP is coated with an ion resolution. In addition, the MCP is coated with an ion barrier film for increased tube life. The light barrier film for increased tube life. The light amplification is also improved, to around 30000-amplification is also improved, to around 30000-50000x 50000x

Examples:Examples: AN/PVS-7AN/PVS-7 NVS-7NVS-7 AN/PVS-14AN/PVS-14 NVS-14NVS-14 XD-4, autogated or notXD-4, autogated or not

Advantage of Gen 3 over Advantage of Gen 3 over Gen 2Gen 2

Gen 3 technology improves night operational Gen 3 technology improves night operational effectiveness for military users of night vision effectiveness for military users of night vision goggles and other night vision devices. The goggles and other night vision devices. The filmless MCP provides a higher signal-to-noise filmless MCP provides a higher signal-to-noise ratio than Gen 2, resulting in better image ratio than Gen 2, resulting in better image quality (less scintillation) under low-light quality (less scintillation) under low-light conditions. The gated power supply further conditions. The gated power supply further improves image resolution under high light improves image resolution under high light conditions, and the reduced halo minimizes conditions, and the reduced halo minimizes interference from bright light sources. These interference from bright light sources. These improvements also substantially increase the improvements also substantially increase the detection range of the systedetection range of the syste

Continued……Continued……

GEN 2 GEN 3 % Improvement

Photoresponse(µA/Im)

1800 1800 -

Signal-to-Noise Ratio

21.0 25 20% Higher

Resolution(lp/mm)

64 64 -

Halo(mm) 1.25 0.75 40% Smaller

Reliability(hours)

10,000 10,000 -

Cou

rtesy

of

Matt

L

ast

Detection RangeDetection Range

Gen 1SuperG

en 1

Gen 2OMNI

I and II

Gen 2 OMNI

III

Gen 2 OMNI

IVGen 3

Detection Range

(m)170 270 240 290 360 430

% Improve

mentover

Gen 1

0% 60% 40% 70% 110% 153%

How Far Can We See ??How Far Can We See ?? There are many different variables that can effect the There are many different variables that can effect the

distance that you we see with a Night Vision device.distance that you we see with a Night Vision device. First which object we want to see.First which object we want to see. The larger the object the easier it is too see.The larger the object the easier it is too see. Second. Another variable is lighting conditions. The Second. Another variable is lighting conditions. The

more ambient light we have (starlight, moonlight, more ambient light we have (starlight, moonlight, infrared light) the better and further we will be able to infrared light) the better and further we will be able to see .If it is cloudy and overcast then we typically state see .If it is cloudy and overcast then we typically state that we can tell the difference between a male and a that we can tell the difference between a male and a female or a dog and a deer at about 75 to 100 yards.female or a dog and a deer at about 75 to 100 yards.

If there is ambient light then we can see about 500 If there is ambient light then we can see about 500 yards.yards.

BLACK SPOTS ON THE BLACK SPOTS ON THE SCREENSCREEN

As we look through a As we look through a night vision device we night vision device we may notice black spots may notice black spots on the screen. A NVD is on the screen. A NVD is similar to a television similar to a television screen and attracts dust screen and attracts dust and dirt. Typically these and dirt. Typically these spots can be cleaned.spots can be cleaned.

These black spots will These black spots will not affect the not affect the performance or performance or reliability of the night reliability of the night vision device.vision device.

USAGEUSAGE

Night vision devices were originally Night vision devices were originally developed for military use, but have developed for military use, but have since spread into other areas, such since spread into other areas, such as security and police work, rescue as security and police work, rescue outfits and various amateur uses (for outfits and various amateur uses (for example animal watching or example animal watching or hunting).hunting).

ConclusionConclusion

Through night vision device we can Through night vision device we can see the object in dark environment.see the object in dark environment.

We have seen four generation of this We have seen four generation of this devices and seen different ranges.devices and seen different ranges.

Initially this device was used by Initially this device was used by military but now it also available for military but now it also available for civilians.civilians.

ReferencesReferences

1.WWW.WIKIPEDIA.ORG1.WWW.WIKIPEDIA.ORG

2.EN.WIKIPEDIA.ORG/WIKI/2.EN.WIKIPEDIA.ORG/WIKI/NIGHT_VISION_DEVICENIGHT_VISION_DEVICE

3.WWW.MOROVISION.COM/3.WWW.MOROVISION.COM/HOW_THERMAL_IMAGING_WORKS.HTMHOW_THERMAL_IMAGING_WORKS.HTM

4.EN.WIKIPEDIA.ORG/WIKI/NIGHT_VISION4.EN.WIKIPEDIA.ORG/WIKI/NIGHT_VISION

Thank YouThank You

Presented byPresented byRandhir Kumar parmarRandhir Kumar parmar

Roll No: 67Roll No: 67

C.S. ‘B’C.S. ‘B’

S.O.E., CUSATS.O.E., CUSAT

Questions??Questions??