Night vision technology by shudhanshu agarwal

NIGHT VISION TECHNOLOGYNIGHT VISION TECHNOLOGY ( NIGHT VISION DEVICE )( NIGHT VISION DEVICE )

Presented by:-Presented by:-

Shudhanshu agarwalShudhanshu agarwal

EC-11EC-11

WHAT WE WILL COVER!WHAT WE WILL COVER!

What is night visionWhat is night vision Night vision approachesNight vision approaches Working of night vision technologyWorking of night vision technology Night vision DevicesNight vision Devices GenerationGeneration UsageUsage

Night Vision!!!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 possible by combination of two approaches: sufficient is possible by combination of two approaches: sufficient spectral range, and sufficient intensity rangespectral range, and sufficient intensity range

Human have poor night vision compared to many animals Human have poor night vision compared to many animals because the human eye does not have tapetum lucidumbecause the human eye does not have tapetum lucidum

Tapetum lucidum is a layer of tissue in the eye of many Tapetum lucidum is a layer of tissue in the eye of many animals which improves vision in low night condition.animals which improves vision in low night condition.

Night Night Vision Approaches!!Vision Approaches!!

Spectral rangeSpectral range Night-useful spectral range Night-useful spectral range

techniques can sense radiation techniques can sense radiation that is invisible to a human that is 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 of electromagnetic radiation (such as near-infrared or (such as near-infrared or ultraviolet radiation). ultraviolet radiation).

Intensity range:Intensity range:

Sufficient intensity range is simply the ability to Sufficient intensity range is simply the ability to see with very small quantities of light.see with very small quantities of light.

Many animals have better night vision than Many animals have better night vision than humans do, the result of one or more differences humans do, the result of one or more differences in the morphology and anatomy of their eyes. in the morphology and anatomy of their eyes. These include having a larger eyeball, a larger These include having a larger eyeball, a larger lens, a larger optical aperture (the pupils may lens, a larger optical aperture (the pupils may expand to the physical limit of the eyelids), more expand to the physical limit of the eyelids), more rods than cones (or rods exclusively) in the rods than cones (or rods exclusively) in the retina, and a tapetum lucidum.retina, and a tapetum lucidum.

Working of night vision devices!!Working of night vision devices!!

Night vision technologies can be broadly divided into two main categories:Night vision technologies can be broadly divided into two main categories: Image intensification

Image intensification technologies work on the principle of Image intensification technologies work on the principle of magnifying the amount of received photons from various natural magnifying the amount of received photons from various natural sources such as starlight or moonlight. sources such as starlight or moonlight.

Thermal imaging Thermal imaging technologies work by detecting the temperature Thermal imaging technologies work by detecting the temperature

difference between the background and the foregrounddifference between the background and the foreground

1)IMAGE INTENSIFICATION !!!!1)IMAGE INTENSIFICATION !!!!

This method of night vision amplifies the available light This method of night vision amplifies the available light to achieve better vision. An objective lens focuses to achieve better vision. An objective lens focuses available light (photons) on the photocathode of an available light (photons) on the photocathode of an image intensifier. The light energy causes electrons to be image intensifier. The light energy causes electrons to be released from the cathode which are accelerated by an released from the cathode which are accelerated by an electric field to increase their speed (energy level). These electric field to increase their speed (energy level). These electrons enter holes in a micro channel plate and bounce electrons enter holes in a micro channel plate and bounce off the internal specially-coated walls which generate off the internal specially-coated walls which generate more electrons as the electrons bounce through. more electrons as the electrons bounce through.

Night vision goggles are electro-optical Night vision goggles are electro-optical devices that intensify existing light devices that intensify existing light instead of relying on a light source. instead of relying on a light source. Image intensifiers capture ambient light Image intensifiers capture ambient light and amplify it thousands of times by and amplify it thousands of times by electronic means to display the battlefield electronic means to display the battlefield to a soldier via a phosphor display, hence to a soldier via a phosphor display, hence why it becomes green.why it becomes green.

Green is a good choice for two reasons. Green is a good choice for two reasons. One is that the phosphors, the things that One is that the phosphors, the things that glow and make the colour are relatively glow and make the colour are relatively easy to make it green. And because the easy to make it green. And because the eye is more sensitive to green light than eye is more sensitive to green light than virtually any other wavelength, it means virtually any other wavelength, it means that you can make your display dimmer that you can make your display dimmer than any other wavelength and your eye than any other wavelength and your eye will be sensitive to it. will be sensitive to it.

2)THERMAL IMAGING!!!2)THERMAL IMAGING!!!

WORKING OF THERMAL IMAGING!!!WORKING OF THERMAL IMAGING!!!

Infrared thermography, thermal imaging, and thermal video are Infrared thermography, thermal imaging, and thermal video are examples of infrared imaging science. examples of infrared imaging science.

Thermal imaging cameras detect radiation in the infrared range of the Thermal imaging cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 9000–14,000 nanometers or 9–14 electromagnetic spectrum (roughly 9000–14,000 nanometers or 9–14 µm) and produce images of that radiation, called thermo grams. Since µm) and produce images of that radiation, called thermo grams. Since infrared radiation is emitted by all objects above absolute zero according infrared radiation is emitted by all objects above absolute zero according to the black body radiation law, thermography makes it possible to see to the black body radiation law, thermography makes it possible to see one's environment with or without visible illumination. one's environment with or without visible illumination.

When viewed through a thermal imaging camera, warm objects stand out When viewed through a thermal imaging camera, warm objects stand out well against cooler backgrounds; humans and other warm-blooded well against cooler backgrounds; humans and other warm-blooded animals become easily visible against the environment, day or night. As animals become easily visible against the environment, day or night. As a result, thermography is particularly useful to military and other users of a result, thermography is particularly useful to military and other users of surveillance cameras. surveillance cameras.

Night Vision Devices!!!Night Vision Devices!!!

A night vision device (NVD) is an A night vision device (NVD) is an optical instrument that allows optical instrument that allows images to be produced in levels of images to be produced in levels of light approaching total darkness.light approaching total darkness.

They are most often used by the They are most often used by the military and law enforcement military and law enforcement agencies, but are available to agencies, but are available to civilian users. civilian users.

The term usually refers to a The term usually refers to a complete unit, including an image complete unit, including an image intensifier tube, a protective and intensifier tube, a protective and generally water-resistant housing, generally water-resistant housing, and some type of mounting system. and some type of mounting system.

1) Night glasses1) Night glasses

Night glasses are Night glasses are telescopes or binoculars telescopes or binoculars with a large diameter with a large diameter objective. Large lenses can objective. Large lenses can gather and concentrate gather and concentrate light, thus intensifying light light, thus intensifying light with purely optical means with purely optical means and enabling the user to see and enabling the user to see better in the dark than with better in the dark than with the naked eye alonethe naked eye alone

2) Thermal vision2) Thermal vision

Thermal imaging cameras Thermal imaging cameras are excellent tools for night are excellent tools for night vision. They detect thermal vision. They detect thermal radiation and do not need a radiation and do not need a source of illumination. source of illumination. They produce an image in They produce an image in the darkest of nights and the darkest of nights and can see through light fog, can see through light fog, rain and smokerain and smoke. .

3) Image intensifier3) Image intensifier

The image intensifier is a vacuum-tube based device The image intensifier is a vacuum-tube based device that converts visible light from an image so that a that converts visible light from an image so that a dimly lit scene can be viewed by a camera or the dimly lit scene can be viewed by a camera or the naked eye. While many believe the light is naked eye. While many believe the light is "amplified," it is not. "amplified," it is not.

GenerationsGenerations!!!!!!!! Generation 0Generation 0 Generation 1 (GEN I)Generation 1 (GEN I) Generation 2 (GEN II)Generation 2 (GEN II) Generation 3 (GEN III)Generation 3 (GEN III) Omnibus-VII (GEN III+)Omnibus-VII (GEN III+)

Generation 0Generation 0

At that time infra-red was commonly called black light, a At that time infra-red was commonly called black light, a term later restricted to Ultraviolet. It was not a success due term later restricted to Ultraviolet. It was not a success due to its size and cost. They were active devices, using a large to its size and cost. They were active devices, using a large infrared light source to illuminate targets. Their image infrared light source to illuminate targets. Their image intensifier tubes function using an anode and an S-1 intensifier tubes function using an anode and an S-1 photocathode, made primarily of silver, cesium, and oxygen photocathode, made primarily of silver, cesium, and oxygen and a electrostatic inversion with electron acceleration were and a electrostatic inversion with electron acceleration were used to achieve gain.used to achieve gain.

Generation 1 (GEN I)Generation 1 (GEN I)

First generation passive devices, introduced during First generation passive devices, introduced during the Vietnam War, were an adaptation of earlier the Vietnam War, were an adaptation of earlier active GEN 0 technology, and rely on ambient light active GEN 0 technology, and rely on ambient light instead of an infrared light source. Using an S-20 instead of an infrared light source. Using an S-20 photocathode, their image intensifiers produce a photocathode, their image intensifiers produce a light amplification of around 1,000×, but are quite light amplification of around 1,000×, but are quite bulky and require moonlight to function properly.bulky and require moonlight to function properly.

Examples:Examples: AN/PVS-2 Starlight scopeAN/PVS-2 Starlight scope

Generation 2 (GEN II)Generation 2 (GEN II)

Second generation devices feature an improved image-Second generation devices feature an improved image-intensifier tube utilizing micro-channel plate (MCP) with an intensifier tube utilizing micro-channel plate (MCP) with an S-25 photocathode, resulting in a much brighter image, S-25 photocathode, resulting in a much brighter image, especially around the edges of the lens. This leads to especially around the edges of the lens. This leads to increased illumination in low ambient light environments, increased illumination in low ambient light environments, such as moonless nights. Light amplification is around such as moonless nights. Light amplification is around 20,000×. Also improved were image resolution and 20,000×. Also improved were image resolution and reliability.reliability.

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

Generation 3 (GEN III)Generation 3 (GEN III)

Third generation night vision systems maintain the MCP from Gen II, Third generation night vision systems maintain the MCP from Gen II, but now use a photocathode made with gallium arsenide, which further but now use a photocathode made with gallium arsenide, which further improves image resolution. In addition, the MCP is coated with an ion improves image resolution. In addition, the MCP is coated with an ion barrier film for increased tube life. The light amplification is also barrier film for increased tube life. The light amplification is also improved to around 30,000–50,000×.Power consumption is higher than improved to around 30,000–50,000×.Power consumption is higher than GEN II tubes.GEN II tubes.

Examples:Examples: AN/PVS-7 AN/PVS-7 AN/NVS-7 AN/NVS-7 AN/PVS-10 AN/PVS-10 AN/PVS-14 AN/PVS-14 AN/PNVS-14 AN/PNVS-14

Omnibus-VII (GEN III+)Omnibus-VII (GEN III+)

GEN-III OMNI-VII devices can differ from standard Generation 3 in GEN-III OMNI-VII devices can differ from standard Generation 3 in two important ways. First, an automatic gated power supply system two important ways. First, an automatic gated power supply system regulates the photocathode voltage, allowing the NVD to instantaneously regulates the photocathode voltage, allowing the NVD to instantaneously adapt to changing light conditions. The second is a removed or greatly adapt to changing light conditions. The second is a removed or greatly thinned ion barrier. The disadvantage to a thin or removed ion barrier is thinned ion barrier. The disadvantage to a thin or removed ion barrier is the overall decrease in tube life from a theoretical 20,000 hrs mean time the overall decrease in tube life from a theoretical 20,000 hrs mean time to failure (MTTF) for Gen III type, to 15,000 hrs MTTF for GEN IV to failure (MTTF) for Gen III type, to 15,000 hrs MTTF for GEN IV type. However, this is largely negated by the low number of image type. However, this is largely negated by the low number of image intensifier tubes that reach 15,000 hrs of operation before replacement.intensifier tubes that reach 15,000 hrs of operation before replacement.

Examples:Examples: AN/PVS-22 AN/PVS-22

NVS-22NVS-22

USAGEUSAGE

Common applications for night vision include: Common applications for night vision include: Military Military Hunting Hunting Wildlife observationWildlife observation Security Security Navigation Navigation Hidden-object detection Hidden-object detection EntertainmentEntertainment

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