Night Vision Technology

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Night Vision Technology

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A PRESENTATION ON Night vision technology :

A PRESENTATION ON Night vision technology Presented By: Presented to: Pawan Saini ..………………

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Contents Introduction Need for Night Vision Technology Basics Of Night Vision Condition Of Night Vision Types Of Night Vision Low-Light Imaging Thermal Imaging Near Infrared Illumination Generations Of Night Vision Devices Characteristics Of Night Vision Equipments & Devices Application Of NVDs INDIA AND NVDs Future Scope Conclusion

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Introduction "Night Vision” as referenced here is that technology that provides us with the miracle of vision in total darkness and the improvement of vision in low light environments. This technology is an amalgam of several different methods each having its own advantages and disadvantages.

NEED FOR NIGHT VISION TECHNOLOGY:

NEED FOR NIGHT VISION TECHNOLOGY Humans have poor vision of than some animals in several aspects. Night vision ie ability to see in dark environment is one such aspect. Reasons : Lesser number of rod cells than other animals. Absence of tapetum lucidium. Night Vision Technology enables viewing in dark. You can see a person standing over 180 metres on a moonless cloudy night.

BASICS OF NIGHT VISION:

BASICS OF NIGHT VISION Energy in a light wave is related to its wavelength. Shorter the wavelength, larger the energy. Infrared light can be split into three categories : near infrared, mid infrared and thermal infrared. The key difference between thermal-IR and the other two is that thermal-IR is emitted by an object instead of reflected off it. Infrared light is emitted by an object because of what is happening at the atomic level.

AT THE ATOMIC LEVEL:

AT THE ATOMIC LEVEL Once an electron moves to a higher-energy orbit, it eventually wants to return to the ground state. When it does, it releases its energy as a photon -- a particle of light. The photon emitted has a very specific wavelength (color) that depends on the state of the electron's energy when the photon is released.

CONTDITIONS::

CONTDITIONS: Anything that is alive uses energy, and so do many inanimate items such as engines and rockets. Energy consumption generates heat. In turn, heat causes the atoms in an object to fire off photons in the thermal-infrared spectrum. The hotter the object, the shorter the wavelength of the infrared photon it releases. In night vision, thermal imaging takes advantage of this infrared emission. An object that is very hot will even begin to emit photons in the visible spectrum, glowing red and then moving up through orange, yellow, blue and eventually white .

NIGHT VISION TECHNIQUES:

NIGHT VISION TECHNIQUES The most common methods of Night Vision are : Low-Light Imaging. Thermal Imaging. Near-infrared Illumination.

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Low-Light Imaging The most popular and well known method of performing night vision is based on the use of image intensifiers .

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

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Advantages Of Image Intensifiers 1.Excellent low-light level sensitivity. 2.Enhanced visible imaging yields the best possible recognition and identification performance. 3.High resolution. 4.Low power and cost. 5.Ability to identify people.

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Disadvantages Of Image Intensifiers 1.Because they are based on amplification methods, some light is required. 2.This method is not useful when there is essentially no light. 3.Inferior daytime performance when compared to daylight-only methods. 4.Possibility of blooming and damage when observing bright sources under low-light conditions.

THERMAL IMAGING:

THERMAL IMAGING thermal imaging night vision methods do not require any ambient light at all. They operate on the principal that all objects emit infrared energy as a function of their temperature

CONTDITIONS::

CONTDITIONS: Most thermal-imaging devices can : scan at a rate of 30 times per second. can sense temperatures ranging from -4 degrees Fahrenheit (-20 degrees Celsius) to 3,600 F (2,000 C). can normally detect changes in temperature of about 0.4 F (0.2 C).

TYPES OF THERMAL IMAGING:

TYPES OF THERMAL IMAGING Two types of thermal Imaging are: Un-cooled : Infrared-detector elements are contained in a unit that operates at room temperature Cryogenically cooled :elements sealed inside a container that cools them to below 32 F (0 C). The advantage of such a system is the incredible resolution and sensitivity that result from cooling the elements. Cryogenically-cooled systems can "see" a difference as small as 0.2 F (0.1 C) from more than 1,000 ft (300 m) away, which is enough to tell if a person is holding a gun at that distance!

USEFULNESS OF THERMAL IMAGING:

USEFULNESS OF THERMAL IMAGING It is quite easy to see everything during the day… But at night u can see a little… Thermal Imaging let’s u see again…

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1.The highest possible thermal sensitivity. 2.Able to detect people and vehicles at great distances. 3.Not affected by bright light sources. 4.Able to perform high speed infrared imaging. 5.Able to perform multi-spectral infrared imaging Advantages Of Thermal Imaging

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Disadvantages Of Thermal Imaging 1.Expensive to purchase and to operate. 2.Limited cooler operating lifetime. 3.May require several minutes to cool down upon initiation. 4.Bulky.

Near Infrared Illumination:

Near Infrared Illumination A popular and sometimes inexpensive method for performing night vision is by near infrared illumination. In this method, a device that is sensitive to invisible near infrared radiation is used in conjunction with an infrared illuminator

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Advantages Of Near Infrared Illumination 1.Lowest cost compared to other night vision technologies. 2.Eliminate shadows and reveal identifying lettering, numbers and objects. Can also be used to perform facial identification. 3.Able to perform high-speed video capture (such as reading license plates of moving vehicles). 4.IR illuminators can see through night-time fog, mist, rain and snowfall as well as windows. 5.Eliminates the variability of ambient light.

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Disadvantages Of Near Infrared Illumination Users of infrared illuminators can be detected by others that have near-infrared viewing devices.

GENERATIONS OF NIGHT VISION DEVICES:

GENERATIONS OF NIGHT VISION DEVICES Generation 0-Used in World War II Generation 1-Did not require a source of projected infrared light. Generation 2-ability to see in extremely low light conditions. Generation 3-currently being used bu US army Generation 4-NVD user can respond very quickly to light fluctuations.

CHARACTERISTICS OF NIGHT VISION:

CHARACTERISTICS OF NIGHT VISION Texture, Light and Dark Objects that appear light during the day but have a dull surface nay appear darker, through the night vision unit , than objects that are darks during the day but have a highly reflective surface. Fog And Rain Night vision is very responsible to reflective ambient light. Therefore the light reflecting off of tog or heavy rain causes much more light to go toward the light vision unit and may degrade its performance. Honeycomb This is a faint hexagonal pattern which is the result of the manufacturing process. Black spots A few black spots throughout the image area are also inherent characteristics of all night vision technology. These spot will remain constant and should not increase in size or number

EQUIPMENT AND APPLICATIONS :

EQUIPMENT AND APPLICATIONS Night Goggles Scopes Security Cameras Night Glasses Sensor Fusion Jakks Eyeclops

APPLICATIONS OF NVDs:

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

INDIA AND NVDs:

INDIA AND NVDs India has to maintain tight surveillance not only at its international borders stretching thousands of kilometers, but also has to deal with Naxals , several other insurgent groups and several terrorist groups . Having a better knowledge of rural and wild terrain where they thrive, they have often managed to hoodwink the army and the police, taking advantage of the darkness of night. Recently the Indian government decided to purchase night vision devices worth $30 million from Israel. Encouraged research in developing indigenous Night Vision devices at the Indian Institute of Science, Banglore, to reduce its dependence on other countries

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Advantages Of Night Vision High sensitivity in low-light High speed imaging capability Able to detect people and vehicles at at great distances Eliminates shadows and reveal identifying lettering numbers and Objects

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Disadvantages Of Night Vision 1.Near illumination is required 2.U can get blind if u look at something bright 3.Blooming- night vision images gets partially distorted or completely distorted. 4.Optical distortion-classic & manufacturing 5.Night vision technology in cars

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The United States Air Force is experimenting with Panoramic Night Vision Goggles (PNVGs) which double the user's field of view to around 95 degrees by using four 16 mm image intensifiers tubes, rather than the more standard two 18 mm tubes.And lets hope that more and more advancements will be made in the field of night vision technologies so that we can also “own the night” one day………… Future Scope

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Conclusion 1.Night vision technology was developed by the US defence department mainly for defence purposes 2.Night Vision Technologies are now used in the daily lives. 3.While thermal imaging is great for detecting people or working in near-absolute darkness, most night-vision equipment uses image-enhancement technology. 4.Many people are beginning to discover the unique world that can be found after darkness falls 5.One estimate shows an entire battalion could be outfitted with the ability to "own the night" for less than two million dollars

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Thank You Query…??