07-10-2010, 12:34 PM
NIGHT VISION TECHNOLOGY.pdf (Size: 425.92 KB / Downloads: 431)
NIGHT VISION TECHNOLOGY A SEMINAR REPORT
07-10-2010, 12:34 PM
NIGHT VISION TECHNOLOGY.pdf (Size: 425.92 KB / Downloads: 431) NIGHT VISION TECHNOLOGY A SEMINAR REPORT
29-10-2010, 12:36 AM
Night Vision Technology
Sarath S Panicker College Of Engineering, Kalloopara 2007-11 batch Night Vision Technology.pptx (Size: 2.29 MB / Downloads: 272) Introduction Literally allows one to see in the dark. With the proper night-vision equipment, you can see a person standing over 200 yards away on a moonless, cloudy night. Originally developed for military use. Federal and state agencies now routinely utilize the technology for site security, surveillance as well as search and rescue. Various Night Vision Snaps Night Vision Technology Night Vision can work in two different ways depending on the technology used. 1.Image enhancement 2:Thermal imaging Image enhancement Image Enhancement Collects the tiny amounts of light including the lower portion of the infrared light spectrum. & Amplify it to the point that we can easily observe the image. How Image Enhancement works? Objective lens captures ambient light and some near-infrared light. The gathered light is sent to the image-intensifier tube. The tube outputs a high voltage to the image-tube components. The image-intensifier tube has a photocathode, which is used to convert the photons of light energy into electrons. As the electrons pass through the tube, similar electrons are released from atoms in the tube, multiplying the original number of electrons using a microchannel plate (MCP) in the tube. At the end of the image-intensifier tube, the electrons hit a screen coated with phosphors. The energy of the electrons causes the phosphors to reach an excited state and release photons. The green phosphor image is viewed through the ocular lens, which allows you to magnify and focus the image. Thermal Imaging Captures the upper portion of the infrared light spectrum, which is emitted as heat by objects. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings. How Thermal Imaging Works? A special lens focuses the IR emitted by all of the objects in view. The focused light is scanned by a phased array of infrared-detector elements. The detector elements create a very detailed temperature pattern called a thermogram. The thermogram is translated into electric impulses The impulses are sent to a signal-processing unit, that translates the information from the elements into data for the display. The signal-processing unit sends the information to the display, where it appears as various colors depending on the intensity of the IR emission. Thermal Imaging Devices Two Types: Un-cooled : Contained in a unit that operates at room temperature. Completely quiet. Activates immediately. In-built battery. Cryogenically cooled : Elements sealed inside a container that cools them to below zero C. Incredible resolution. High Sensitivity. Night Vision Products GENERATION 1 (Developed in 1960's) Vacuum Tube Technology Full Moon Operation Amplification: 1,000 Operating Life: 2,000 Hours GENERATION 2 (Developed in 1970's) First Micro channel Plate (MCP) Application One-Quarter Moon Operation Amplification: 20,000 Operating Life: 2,500 Hours GENERATION 2+ (1970s) Development increased image tube bias voltage to improve gain. Additionally, a glass faceplate was added to improve resolution. GENERATION 3 (Developed in 1990's) Improved MCP & Photocathode Starlight Operation Amplification: 40,000 Operating Life: 10,000 Hour GENERATION 4 Enhanced (2000's) Improvements in the photocathode and MCP resulted in increased gain and resolution. An improvement over GEN 2 & 3 Night Vision Equipments Characteristics of Night Vision Some of the aspects of night vision that you should be aware of when you are using an image intensified night vision system. Textures, Light and Dark Depth Perception Fog and Rain Honeycomb Black Spots Applications Military Law enforcement Hunting Wildlife observation Surveillance Security Navigation Hidden-object detection Advantages 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 Disadvantages Near illumination is required U can get blind if u look at something bright Blooming- night vision images gets partilaaly distorted or completely distored. Optical distortion-classic&manufacturing Night vision technology in cars Conclusion Night vision technology was developed by the US defense department mainly for defense purposes Night Vision Technologies are now used in the daily lives. While thermal imaging is great for detecting people or working in near-absolute darkness, most night-vision equipment uses image-enhancement technology. Many people are beginning to discover the unique world that can be found after darkness falls One estimate shows an entire battalion could be outfitted with the ability to "own the night" for less than two million dollars In future many Other method will used for efficient way of working of Night Vision Technology Future Scope 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………… References 1. www.answer.com 2. www.nightvision.com 3. www.google.com 4. www.wikipedia.org Night Vision Technology.pptx (Size: 2.29 MB / Downloads: 272)
15-02-2011, 04:21 PM
I want ppt and project reprt on it! I am unable to find link of it ! !
19-02-2011, 10:22 AM
NIGHT VISION TECHNOLOGY
Abstract: Apart from many technologies in the present world, NIGHT VISION TECHNOLOGY is one of the most used technologies, in many fields. This technology helps in discovering the world that is present in darkness. The implementation of this technology is done properly through night-vision equipment. This NIGHT VISION TECHNOLOGY uses the equipment NIGHT VISION DEVICES also called NVD`s for identifying a person who is approximately 183m away from the moonlight. This uses the concept of infrared rays. In this technology it uses two methods for the detection. Both methods work in two different levels. The development in the technology has made its implementation to extend into many fields. The original purpose of night vision is was to locate enemy targets at night. But its requirement has been considered also in the fields of Surveillance, Hidden-object detection, Entertainment, Wild life detection and in Navigation. My paper deals with the two methods by which this technology works.
16-03-2011, 04:29 PM
presented by:
Y. Shiva kumar NIGHT VISION TECHNOLOGY.docx (Size: 191.99 KB / Downloads: 176) NIGHT VISION TECHNOLOGY Introduction: NVT allows us to see in the dark Originally developed for military use Now used for site security, surveillance as well as search and rescue Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology. Types of night vision: Categorized by generations Each substantial change NVT establishes a new generation Categorized into: Generations- 0 , 1, 2 , 3 , 4 . Generation-0: Created by US Army Uses active infrared A projection unit called IR illuminator is attached Full moon operation Use anode in conjunction with cathode to accelerate the electrons Problems –acceleration causes distortion of image as well as reduction of life of the tube Also, it was quickly duplicated by the hostile nations Generation-1 (1960’s): Uses passive infrared Uses ambient light provided by the moon and the stars Don’t require a source of projected infrared light Don’t work well on cloudy or moonless nights One quarter moon operation Uses same image-intensifier tube technology as Generation-0 Same problems as faced by the Generation-0 Generation-2 (1970’s) Offer improved resolution and performance over Generation-1 devices Considerably more reliable Able to see in extreme low light conditions due to the addition of microchannel plate(MCP) to the image-intensifier tube The images are less distorted and brighter Generation-3 (1990’s) Currently used by the US Army Better resolution and sensitivity Photocathode is made up of Gallium Arsenide MCP is coated with an ion barrier Tube life is increased Generation-4 (2000’s) Known as “filmless and gated” technology Shows significant improvement in both high- and low-level light environments No ion barrier in MCP Responds quickly to different lightning conditions Reduced background noise Enhances signal to noise ratio Images are less distorted and brighter Thermal imaging This technology operates by capturing upper portion of the infrared light spectrum, which is emitted as heat Hotter objects emit more of this light than the cooler objects These elements then create a thermogram Thermogram àelectric pulsesà display data
22-03-2011, 04:06 PM
PRESENTED BY
MANJEERA ANITHA NIGHT_ VISION_TECH_PPT.ppt (Size: 1.35 MB / Downloads: 221) NIGHT VISION TECHNOLOGY Introduction NVT allows us to see in the dark Originally developed for military use Now used for site security, surveillance as well as search and rescue Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology. Types of night vision Categorized by generations Each substantial change NVT establishes a new generation Categorized into: Generation-0 Generation-1 Generation-2 Generation-3 Generation-4 Generation-0 Created by US Army Uses active infrared A projection unit called IR illuminator is attached Full moon operation Use anode in conjunction with cathode to accelerate the electrons Problems –acceleration causes distortion of image as well as reduction of life of the tube Also, it was quickly duplicated by the hostile nations Generation-1 (1960’s) Uses passive infrared Uses ambient light provided by the moon and the stars Don’t require a source of projected infrared light Don’t work well on cloudy or moonless nights One quarter moon operation Uses same image-intensifier tube technology as Generation-0 Same problems as faced by the Generation-0 Generation-2 (1970’s) Offer improved resolution and performance over Generation-1 devices Considerably more reliable Able to see in extreme low light conditions due to the addition of microchannel plate(MCP) to the image-intensifier tube The images are less distorted and brighter Generation-3 (1990’s) Currently used by the US Army Better resolution and sensitivity Photocathode is made up of Gallium Arsenide MCP is coated with an ion barrier Tube life is increased Generation-4 (2000’s) Known as “filmless and gated” technology Shows significant improvement in both high- and low-level light environments No ion barrier in MCP Responds quickly to different lightning conditions Reduced background noise Enhances signal to noise ratio Images are less distorted and brighter Thermal imaging This technology operates by capturing upper portion of the infrared light spectrum, which is emitted as heat Hotter objects emit more of this light than the cooler objects These elements then create a thermogram Thermogram àelectric pulsesà display data 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. Thermal imaging Thermal imaging devices Two types: 1. Uncooled. 2. Cryogenically cooled. Great for detecting people or working in near-absolute darkness Image Enhancement It is also known as Image intensification Relies on image intensifier tube to collect an amplify infrared and visible light Lens captures the light which is then sent to image intensifier tube It has photocathode that converts photons into electrons When electrons pass through MCP ,more electrons are presented This causes chain reaction where atoms are released Electrons reach phosphor screen and photons are released Those phosphor create green image Performance Attributes Sensitivity (photo response)- tube’s ability to detect the available light Signal- plays a key role in night vision’s performance Resolution- ability to dissolve detail in the image Technical Characteristics Textures, Light and Dark Depth Perception Fog and Rain Honeycomb Spots Equipments Three categories Scopes Goggles Cameras Equipments Scopes- monocular, handheld, better look at a specific object and then return to normal viewing conditions. Goggles- binocular, handheld or worn, excellent for constant viewing Cameras- send the image to a monitor for display or to a VCR for recording. Applications Military Law enforcement Hunting Wild life observation Surveillance Security Navigation Hidden-object detection Entertainment 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. 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. Conclusions Although the term ``night vision'' currently encompasses three distinct technologies, it is the evolution of image intensification technology that first made devices practical and widely used. Their success was the result of advancements in light amplification and resolution techniques.
25-03-2011, 12:18 PM
i want development of night vision devices . ther past , present , n future aspects
04-04-2011, 04:33 PM
Presented By:
Vrishali Atrey Night Vision.ppt (Size: 321.5 KB / Downloads: 129) [/u] Introduction NVT allows us to see in the dark Originally developed for military use Now used for site security, surveillance as well as search and rescue Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology. Types of night vision Categorized by generations Generation-1 Generation-2 Generation-3 Generation-4 Mainly divided into 2 categories Thermal imaging Image Enhancement Generation-1 (1960’s) Uses passive infrared Uses ambient light provided by the moon and the stars Don’t require a source of projected infrared light Don’t work well on cloudy or moonless nights One quarter moon operation Generation-2 (1970’s) Offer improved resolution and performance over Generation-1 devices Considerably more reliable Able to see in extreme low light conditions due to the addition of micro channel plate(MCP) to the image-intensifier tube The images are less distorted and brighter. Generation-3 (1990’s) Currently used by the US Army Better resolution and sensitivity Photocathode is made up of Gallium Arsenide MCP is coated with an ion barrier Tube life is increased Generation-4 (2000’s) Known as “film less and gated” technology Shows significant improvement in both high- and low-level light environments No ion barrier in MCP Responds quickly to different lightning conditions Reduced background noise Enhances signal to noise ratio Images are less distorted and brighter • Technologies used in night vision • Night vision can work in two very different ways, depending on the technology used : 1. Image Enhancement. 2. Thermal Imaging. Thermal imaging This technology operates by capturing upper portion of the infrared light spectrum, which is emitted as heat Hotter objects emit more of this light than the cooler objects These elements then create a thermogram Thermogram àelectric pulsesà display data • The basic components of a “Thermal-imaging system” • Thermal imaging Thermal imaging devices Two types: 1. Uncooled. 2. Cryogenically cooled. Great for detecting people or working in near-absolute darkness Image Enhancement It is also known as Image intensification Relies on image intensifier tube to collect an amplify infrared and visible light Lens captures the light which is then sent to image intensifier tube It has photocathode that converts photons into electrons When electrons pass through MCP ,more electrons are presented This causes chain reaction where atoms are released Electrons reach phosphor screen and photons are released Those phosphor create green image Image Enhancement • Image Enhancement Technology used in NVD Technical Characteristics Textures, Light and Dark Depth Perception Fog and Rain Honeycomb Spots Equipments Three categories Scopes Goggles Cameras Scopes- monocular, handheld, better look at a specific object and then return to normal viewing conditions. • Goggles- binocular, handheld or worn, excellent for constant viewing • Cameras- send the image to a monitor for display or to a VCR for recording. • Soldiers using DARK INVADER night-vision Goggles Applications Military Law enforcement Hunting Wild life observation Surveillance Security Navigation Hidden-object detection Entertainment Conclusions Although the term “night vision” currently encompasses three distinct technologies, it is the evolution of image intensification technology that first made devices practical and widely used. Their success was the result of advancements in light amplification and resolution techniques.
14-04-2011, 02:09 PM
SUBMITTED BY :
NEENA M. ROCHE dk.ppt (Size: 2.9 MB / Downloads: 137) Introduction NVT allows us to see in the dark Originally developed for military use Evolved from bulky optical instruments in lightweight goggles through the advancement of image intensification technology. Types of night vision Categorized by generations Each substantial change NVT establishes a new generation Categorized into: Generation-0 Generation-1 Generation-2 Generation-3 Generation-4 Generation-0 Uses active infrared A projection unit called IR illuminator is attached Full moon operation Use anode in conjunction with cathode to accelerate the electrons Problems –acceleration causes distortion of image as well as reduction of life of the tube Also, it was quickly duplicated by the hostile nations Generation-1 (1960’s) Uses passive infrared Uses ambient light provided by the moon and the stars Light amplification is around 1000x Don’t require a source of projected infrared light Don’t work well on cloudy or moonless nights One quarter moon operation Uses same image-intensifier tube technology as Generation-0 Same problems as faced by the Generation-0 Generation-2 (1970’s) Offer improved resolution and performance over Generation-1 devices Considerably more reliable Able to see in extreme low light conditions due to the addition of micro channel plate(MCP) to the image-intensifier tube The images are less distorted and brighter Light amplification is around 20000x Generation-3 (1990’s) Currently used by the US Army Better resolution and sensitivity Photocathode is made up of Gallium Arsenide MCP is coated with an ion barrier Tube life is increased Light amplification is around 30000 to 50000x Generation-4 (2000’s) Known as “filmless and gated” technology Shows significant improvement in both high- and low-level light environments No ion barrier in MCP Responds quickly to different lightning conditions Reduced background noise Enhances signal to noise ratio Images are less distorted and brighter Thermal imaging This technology operates by capturing upper portion of the infrared light spectrum, which is emitted as heat Hotter objects emit more of this light than the cooler objects These elements then create a thermogram Thermogram electric pulses display data Thermal imaging detectors Two types: Uncooled :The infrared detector elements are contained in a unit that operates at room temperature. Cryogenically cooled: These are the systems sealed inside a container that cools below 32F. Great for detecting people or working in near-absolute darkness Image Enhancement It is also known as Image intensification Relies on image intensifier tube to collect an amplify infrared and visible light Lens captures the light which is then sent to image intensifier tube It has photocathode that converts photons into electrons When electrons pass through MCP ,more electrons are presented This causes chain reaction where atoms are released Electrons reach phosphor screen and photons are released Those phosphor create green image Performance Attributes Sensitivity (photo response)- tube’s ability to detect the available light Signal- plays a key role in night vision’s performance Resolution- ability to dissolve detail in the image Technical Characteristics Textures, Light and Dark Depth Perception Fog and Rain Honeycomb Spots Equipments Three categories: Scopes Goggles Cameras
19-04-2011, 01:08 PM
Night vision(praveen)1.doc (Size: 76 KB / Downloads: 92) Night vision Night vision is the ability to see in a dark environment. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range. Humans have poor night vision compared to many animals, in part because the human eye lacks a tapetum lucidum. Types of ranges Spectral range Night-useful spectral range techniques can sense radiation that is invisible to a human observer. Human vision is confined to a small portion of the electromagnetic spectrum called visible light. Enhanced spectral range allows the viewer to take advantage of non-visible sources of electromagnetic radiation (such as near-infrared or ultraviolet radiation). Some animals can see using much more of the infrared and/or ultraviolet spectrum than humans. Intensity range Sufficient intensity range is simply the ability to see with very small quantities of light. Although the human visual system can, in theory, detect single photons under ideal conditions, the neurological noise filters limit sensitivity to a few tens of photons, even in ideal conditions. Many animals have better night vision than humans do, the result of one or more differences in the morphology and anatomy of their eyes. These include having a larger eyeball, a larger lens, a larger optical aperture (the pupils may expand to the physical limit of the eyelids), more rods than cones (or rods exclusively) in the retina, a tapetum lucidum. Enhanced intensity range is achieved via technological means through the use of an image intensifier, gain multiplication CCD, or other very low-noise and high-sensitivity array of photodetectors. Night vision technologies Night vision technologies can be broadly divided into three main categories: Image intensification Image intensification technologies work on the principle of magnifying the amount of received photons from various natural sources such as starlight or moonlight. Examples of such technologies include night glasses and low light cameras. Active illumination Active illumination technologies work on the principle of coupling imaging intensification technology with an active source of illumination in the near infrared (NIR) or shortwave infrared (SWIR) band. Examples of such technologies include low light cameras. Thermal imaging Thermal imaging technologies work by detecting the temperature difference between the background and the foreground objects. Examples of some night vision technologies Night glasses Night glasses are telescopes or binoculars with a large diameter objective. Large lenses can gather and concentrate light, thus intensifying light with purely optical means and enabling the user to see better in the dark than with the naked eye alone. Often night glasses also have a fairly large exit pupil of 7 mm or more to let all gathered light into the user's eye. However, many people can't take advantage of this because of the limited dilation of the human pupil. To overcome this, soldiers were sometimes issued atropine eye drops to dilate pupils. Before the introduction of image intensifiers, night glasses were the only method of night vision, and thus were widely utilized, especially at sea. Second World War era night glasses usually had a lens diameter of 56 mm or more with magnification of seven or eight. Major drawbacks of night glasses are their large size and weight. Active infrared Active infrared night vision combines infrared illumination of spectral range 700-1000nm (just below the visible spectrum of the human eye) with CCD cameras sensitive to this light. The resulting scene, which is apparently dark to a human observer, appears as a monochrome image on a normal display device. Because active infrared night vision systems can incorporate illuminators that produce high levels of infrared light, the resulting images are typically higher resolution than other night vision technologies. Active infrared night vision is now commonly found in commercial, residential and government security applications, where it enables effective night time imaging under low light conditions. However, since active infrared light can be detected by night vision goggles, it is generally not used in tactical military operations. Laser range gated imaging Laser range gated imaging is another form of active night vision which utilizes a high powered pulsed light source for illumination and imaging. Range gating is a technique which controls the laser pulses in conjunction with the shutter speed of the camera's detectors. Gated imaging technology can be divided into single shot, where the detector captures the image from a single light pulse to multi-shot, where the detector integrates the light pulses from multiple shots to form an image. One of the key advantages of this technique is the ability to perform target recognition as opposed to detection with thermal imaging. Thermal vision(Thermal imaging cameras) Thermal imaging cameras are excellent tools for night vision. They perceive thermal radiation and do not need a source of illumination. They produce an image in the darkest of nights and can see through light fog, rain and smoke. Thermal imaging cameras make small temperature differences visible. Thermal imaging cameras are widely used to complement new or existing security networks. Image intensifier The image intensifier is a vacuum-tube based device that converts visible light from an image so that a dimly lit scene can be viewed by a camera or the naked eye. While many believe the light is "amplified," it is not. When light strikes a charged photocathode plate, electrons are emitted through a vacuum tube that strike the microchannel plate that cause the image screen to illuminate with a picture in the same pattern as the light that strikes the photocathode, and is on a frequency that the human eye can see. This is much like a CRT television, but instead of color guns the photocathode does the emitting. The image is said to become "intensified" because the output visible light is brighter than the incoming IR light, and this effect directly relates to the difference in passive and active night vision goggles. Currently, the most popular image intensifier is the drop-in ANVIS module, though many other models and sizes are available at the market.
20-06-2011, 12:34 PM
night vision-ankit tripathi.ppt (Size: 2.14 MB / Downloads: 170) Introduction Night vision technology has shaped history. Pre 1940’s: Flares and spot lights were used for operations at night. Due to the nature of these early night vision devices (NVD), they gave away tactical positions. Military scientists began to think of ways to improve night vision to gain a strategic advantage. Early Development The first night vision devices (NVD) were created during WWII. Functioned by placing an infrared filter over a searchlight. Fighters would use special binoculars to see using the light from the searchlights. Many problems came from this night vision method. 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. Early Development Cont. There were many disadvantages to using the searchlights and flares. The actual searchlight was massive and had to be mounted on a truck or tank. Both the Allies and Nazi’s had this technology, so they each could see the others light. Early Development Cont. The images created were streaky and distorted. The acceleration of electrons cut the life of the image intensification tube, which was the most important and expensive part of the NVD, very short. Military scientists began planning a revised design. Generation 1 Post WWII NVD technology focused on the ability to see without creating additional light. During this time period the first “Generation” of NVD began using intensified natural lighting. Generation 1 Cont. Military scientists created a two-stage cascade image tube. This tube intensified the natural lighting and created a superior image for the viewer. The power of Generation 1 NVD was put to the test in the Vietnam War. Generation 1 Cont. Star Tron Scopes intensification tubes were as heavy as the rifles they were mounted on. They were not sensitive enough to give clear images in anything less than full moonlight. The NVD emitted a whiney noise. They would shut down if they were exposed to a sudden burst of bright light. Generation 2 There were two major developments in NVD technology after their test in Vietnam. The first was a new micro-channel plate (MPC) that was light weight, and more effective at focusing light into clear images. The second major development was the invention of thermal imagining. Generation 2 Cont. Thermal imaging allowed for NV even through low natural lighted conditions. It also allowed for NV through smoky, dusty, and foggy conditions. These thermal imagers were expensive, so in 1973 scientists created a common module that made it less expensive, and more ideal for military use. Generation 2 Cont. The generation 2 NVD were first put to the test by US forces in the early 1990’s during Operation Desert Storm in Kuwait. The dark nights and harsh dusty conditions were perfect for implementing the new technology. Current Generations The currently generations of NVS are generations 3 and 4. Generation 3 is much like generation 2 except for it has a substantially longer life, as well as more defined images. Generation 4 has less noise than generation 3, however it has shorter life. Current Generations Cont. Here is a chart comparing the life in hours of the intensification tube for generations 1-3 General Public Use Development of NVD up until the 1980’s was completely focused around military purposes. In the 80’s, companies in the US and Europe took NVT and found ways to improve everyday civilian life. General Public Use Cont. There are many practical everyday uses for NVD, some of which are: Law Enforcement Hunting Surveillance General Public Use Cont. Security Navigation Hidden-Object detection Entertainment
16-07-2011, 02:03 PM
Presented By: Zaved Ahmad Umesh Pal Singh Lokender Sharm A NIGHT VISION TECHNOLOGY.ppt (Size: 1.23 MB / Downloads: 174) NIGHT VISION TECHNOLOGY The first thing you probably think of when you see the word night vision is a spy or action movie you have seen in which some one straps on pair of night-vision goggles to find some one else in a dark building on a moonless night. And you some one straps on a pair of night-vision goggles to find some one else in dark building on a moonless night . And you have wondered , ‘’Do those think really work? Can you actually see the dark? The answer is most definitely yes. With the proper night-vision equipment you can see a person standing over 200 yards(183m)away on moonless, cloudy night! . How work night-vision? Night vision can work in two different ways 1 Image enhancement. 2 Thermal imaging. This work is collecting the tiny amount of light, including the lower portion of the infrared light spectrum, that are present but may be imperceptible to our eyes, and amplifying to the point thus we can easily observe the image This technology operate by the capturing the upper portion of infrared light spectrum, which is emitted as heat by object instead of simply reflected as light. Hotter object, such as warm bodies emits of this light than cooler objects like trees or building. TYPES OF NIGHT VISION TECHNOLOGY I will tell about two major NIGHT-VISION TECHNOLOGIES. We’ll also discuss the various night vision equipment and applications. But first let’s talk about infrared light In ordered to under stand night vision, it is important to some thing about LIGHT. The amount of energy in a light. Wave is related to its wave length shorter wave length have higher energy. Of visible light, violet has the most energy and red has least just to next is the visible light spectrum is the “infrared spectrum” PART OF INFRARED LIGHT 1 Near-infrared. 2 Mid-infrared. 3 Thermal-infrared. Near infrared closet to visible light, near infrared has wavelengths that range from 0.7 to 1.33’microns’ Mid infrared light has ranging from 1.33 to 3 microns. Both are used by a verity of electronic devices, including’ remote control’ . It occupying the largest part of the infrared spectrum, thermal infrared has wave length ranging from 3 microns to over thirty microns The key difference between thermal-IR and other two is that thermal-IR is emitted by an object instead of reflect off it. IR light is emitted by an object because of what is happing at the atomic level. ATOMS Atoms are constantly in motion. Atoms can be different states of excitation. Atoms can have different energies. The level of excitation depends on amount of energy applied to the atom via heat, light or electricity PROPERTIES OF ATOMS Atoms consist of a nucleus (containing the protons & neutrons )and an electron cloud. Atoms have many orbits. HOW THERMAL IMAGING WORK? A special lens focuses the infrared light emitted by all of object view. The focus light in scanned by a phase array of infrared detector element. The detector element create a very detailed temperature pattern called a thermogram. TYPES OF THERMAL IMAGING DEVICES Most thermal devices scan at the rate of 30 times per second. They can temperature ranging from -4 degrees Fahrenheit (-20 degrees Celsius) to 3600 F (2000 C), and can normally detect changes in temperature of about 0.4 F( 0.2 C). Fig 1:it is quit easy to see every thing in the day. Fig 2:but a night you can see very little. There are two common types of thermal image devices Un-Cooled- this is the most common type of thermal imaging devices. This infrared detector element are contained in a unit that operates a room temperature . This type of system is completely quit, activates immediately and has the battery built right . Cryogenically cooled-more expensive and more susceptible to damage from rough use , these system have the element sealed inside a container that cool them to below 32 F( zero c). Fig: thermal image lets you see again. IMAGE ENHANCE MENT TECHNOLOGY Thermal image technology is a great for detecting people or working in near absolute darkness, most night vision equipment use image enhancement technology HOW IMAGE ENHANCEMENT WORK? A conventional lens called a objective lens, captures ambient light and some near infrared light. The gathered light is sent to the image intensifier tube in most NVD’s the power supply for the image intensifier tube receives power from two N cell. The output of high voltage about 5000 voltage to the image component. The image intensifier has a photocathode, cathode which is used to convert the photons of light energy into electrons. As the end electron pass throw the tube similar electron are released from atoms in the tube. At the end of image intensifier tube, the electron hit a screen coated tube with phosphor. The green phosphor image is viewed through another lens, called the ocular lens. Which allow you to magnify and focus the image. The NVD may be connected to an electric display, such as monitor, or a image may be viewed directly through the ocular lens GENERATION OF NIGHT VISION TECHNOLOGY Generation 0- 1ST GENERATION - The next generation of NVDs moved away from active infrared, using passive infrared instead. Once dubbed Starlight by the U.S. Army, these NVDs use ambient light provided by the moon and stars to augment the normal amounts of reflected infrared in the environment. This means that they did not require a source of projected infrared light. This also means that they do not work very well on cloudy or moonless nights. Generation-1 NVDs use the same image-intensifier tube technology as Generation 0, with both cathode and anode, so image distortion and short tube life are still a problem. 2nd Generation Major improvements in image-intensifier tubes resulted in Generation-2 NVDs. They offer improved resolution and performance over Generation-1 devices, and are considerably more reliable. The biggest gain in Generation 2 is the ability to see in extremely low light conditions, such as a moonless night. This increased sensitivity is due to the addition of the microchannel plate to the image-intensifier tube. Since the MCP actually increases the number of electrons instead of just accelerating the original ones, the images are significantly less distorted and brighter than earlier-generation NVDs. 3rd Generation Generation 3 is currently used by the U.S. military. While there are no substantial changes in the underlying technology from Generation 2, these NVDs have even better resolution and sensitivity. This is because the photo cathode is made using gallium arsenide, which is very efficient at converting photons to electrons. Additionally, the MCP is coated with an ion barrier, which dramatically increases the life of the tube. 4TH GENERATION What is generally known as Generation 4 or "filmless and gated" technology shows significant overall improvement in both low- and high-level light environments. The removal of the ion barrier from the MCP that was added in Generation 3 technology reduces the background noise and thereby enhances the signal to noise ratio. Removing the ion film actually allows more electrons to reach the amplification stage so that the images are significantly less distorted and brighter. Many of the so-called "bargain" night-vision scopes use Generation-0 or Generation-1 technology, and may be disappointing if you expect the sensitivity of the devices used by professionals. Generation-2, Generation-3 and Generation 4 NVDs are typically expensive to purchase, but they will last if properly cared for. Also, any NVD can benefit from the use of an IR Illuminator in very dark areas where there is almost no ambient light to collect. SCOPE Scopes - Normally handheld or mounted on a weapon, scopes are monocular (one eye-piece). Since scopes are handheld, not worn like goggles, they are good for when you want to get a better look at a specific object and then return to normal viewing conditions. GOGGLES &CAMRAS Goggles - While goggles can be handheld, they are most often worn on the head. Goggles are binocular (two eye-pieces) and may have a single lens or stereo lens, depending on the model. Goggles are excellentfor constant viewing, such as moving around in a dark building. Cameras - with night-vision technology can send the image to a monitor for display or to a VCR for recording. When night-vision capability is desired in a permanent location, such as on a building or as part of the equipment in a helicopter, cameras are used. Many of the newer camcorders have night vision built right in. APPLICATIONS Common applications for night vision include: Military Law enforcement Hunting Wildlife observation Surveillance Security Navigation Hidden-object detection Entertainment The original purpose of night vision was to locate enemy targets at night. It is still used extensively by the military for that purpose, as well as for navigation, surveillance and targeting. Police and security often use both thermal-imaging and image-enhancement technology, particularly for surveillance. Hunters and nature enthusiasts use NVDs to maneuver through the woods at night. Detectives and private investigators use night vision to watch people they are assigned to track. Many businesses have permanently-mounted cameras equipped with night vision to monitor the surroundings
31-07-2011, 01:08 PM
pls send me pore information about night vision technology
01-08-2011, 09:57 AM
To get more information about the topic "NIGHT VISION TECHNOLOGY A SEMINAR REPORT " please refer the link below
https://seminarproject.net/Thread-night-...nar-report https://seminarproject.net/Thread-night-...?pid=52992 https://seminarproject.net/Thread-night-...ort?page=4 https://seminarproject.net/Thread-night-...ort?page=3 https://seminarproject.net/Thread-night-...ort?page=5
04-08-2011, 10:11 PM
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