final ppt of night vision
TRANSCRIPT
NIGHT VISION TECHNOLOGY THE BULLETS DONT CARE HOW DARK IT IS
BY
Pradeep.S4MH08EC026
OUTLINEINTRODUCTION THE BASICS OF INFRARED NIGHT VISION THERMAL IMAGING IMAGE ENHANCEMENT GENERATIONS EQUIPMENT AND APPLICATIONS CONCLUSION REFERENCES
INTRODUCTION
What is Night Vision Technology ?
"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 lightenvironments.It is invented by the U.S.Army.
Infrared light is used in this technology.
Humans have poor night vision compared to many animals, in part because the human eye does not have a tapetum lucidum The tapetum lucidum is a layer of tissue in the eye of many animals, that lies immediately behind or sometimes within the retina. It reflects visible light back through the retina, increasing the light available to the photoreceptors. This improves vision in low-light conditions.
THE BASICS OF INFRARED NIGHT VISION
The amount of energy in a light wave is related to its wavelength: Shorter wavelengths have higher energy Of visible light, violet has the most energy, and red has the least. Just next to the visible light spectrum is the infrared spectrum
Infrared light can be split into three categories Near-infrared (near-IR) - Closest to visible light, near-IR has wavelengths that range from 0.7 to 1.3 microns meter. Mid-infrared (mid-IR) - Mid-IR has wavelengths ranging from 1.3 to 3 microns. Both near-IR and mid-IR are used by a variety of electronic devices, including remote controls
Thermal-infrared (thermal-IR) - Occupying the largest part of the infrared spectrum, thermal-IR has wavelengths ranging from 3 microns to over 30 microns
WORKING OF NIGHT VISION DEVICES Night Vision technology consists of two major types: image intensification (light amplification) and Thermal imaging(infrared).
Thermal Imaging / ThermographyDifferent from low-light imaging methods of night vision (which require some ambient light in order to produce an image), 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. In general, thehotter an object is, the more radiation it emits. A thermal imager is a product that collects the infrared radiation from objects in the scene and creates an electronic
imageThermal images are normally black and white in nature, where black objects are cold and white objects are hot. Some thermal cameras show images in color.
Capturing
infrared light
emitted by objects to form images The
cooler the object, the less
clear the image will be Good
for moonless, cloudy
nights
TYPES OF THERMAL IMAGING DEVICES
Un-cooled Infrared Detector: The infrared-detector elements are contained in a unit that operates at room temperature. Bulky in size. Higher reliability than cooled detector thermal imagers .
Cooled Infrared Detector: Expensive and susceptible to damage. infrared-detector elements are sealed inside a container that cools them to below 32 F . Able to detect people and vehicles at great distances. Not affected by bright light sources
IMAGE INTENSIFICATION
It is also called light amplification It is less expensive than thermal Light amplification technology takes the small amount of light, such as moonlight or starlight, that is in the surrounding area, and converts the light energy (scientists call it photons), into electrical energy (electrons)
Disadvantages Possibility of blooming and damage when observing bright sources under low-light conditions Excellent low-light level sensitivity. Because they are based on amplification High resolution. methods, some light is required. This Low power and cost. method is not useful when there is Ability to identify people. essentially no light.
Advantages
All image intensified night vision products on the market today have one thing in common: they produce a green output image
Why do NVD devices always show images in hues of green?
THE IMAGE IS GREEN BECAUSE THE PHOSPHOR IS GREEN IN COLOR THAT IS GOOD FOR HUMAN EYE TO PICK UP DETAIL
Generation-0
Generation-1 (1960s)Uses passive infrared Uses ambient light provided by the moon and the stars Dont require a source of projected infrared light Dont work well on cloudy or moonless nights One quarter moon operation
Created by US Army Uses active infrared A projection unit called IRilluminator is attached Full moon operation
Generation-2 (1970s)Able to see in extreme low light conditions due to the addition of micro
Generation-3 (1990s)Better resolution and sensitivity Photocathode is made up of Gallium Arsenide MCP is coated with an ion barrier Tube life is increased
channel plate(MCP) to the imageintensifier tube The images are less distorted and
brighter
Generation-4 (2000s)Shows significant improvement in both high- and low-level light environments
No ion barrier in MCPResponds quickly to different lightning conditions Reduced background noise Images are less distorted and brighter Generation 1 : eg:-M1,M4 Generation 2 : eg:-AN/PVS-2 Generation 3 : eg:-AN/PVS-4 , SUPER GEN Generation 4 : eg:-AN/PVS-7 , AN/PVS-14, NVS-7 ,NVS-14
HOW FAR CAN WE SEE ??There are many different variables that can effect the distance that we see with a Night Vision device. First which object we want to see. The larger the object the easier it is too see. Second. Another variable is lighting conditions. The more ambient light we have (starlight, moonlight, infrared light) the better and further we will be able to see . If it is cloudy and overcast then we typically state that we can tell the difference between a male and a female or a dog and a deer at about 75 to 100 yards.
Characteristics of Night Vision
Textures, light and dark
Textures, Light and Dark Depth Perception Honey comb Fog and Rain This is a faint hexagonal Honeycomb pattern which is the result of the Spots manufacturing process.
The objects that are clearly visible on day appear dark and vice versa through night vision unit. Fog and Rain Fog and rain reflect more light towards the night vision unit and this may degrade its performance.
BLACK SPOTS ON THE SCREEN
ComparisonInternational Identification range (human)Full moon 0.1lux ( meters) Half moon 0.05lux (meters) Quartermoon 0.01lux ( meters) Starlight 0.001lux ( meters) Overcast 0.0001lux ( meters)
Without nightvision device
230
130
45
_________
________
Generation I Generation II Generation III
300 630 810
200 630 810
150 590 770
100 390 530
50 145 200
NIGHT VISION DEVICES
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 excellent for constant viewing, such as moving around in a dark building.
DARK INVADER Night-vision Goggles 4501
CAMERAS - Cameras with night-vision technology can send the image to a monitor for display. 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. Also used for Wildlife photography and movie making.
Camcorders are a fast growing segment of the night-vision industry
Dark Invader Multipurpose Pocket-Scope
A Soldier equipped with Night Vision Binocular
A Night Vision Long Ranged Binocular
MISSION Night Visions mission is to: Acquire and Target enemy force in battlefield environment. Deny enemy surveillance & acquisition through electro-optic. For night driving and autopilot.
COMMON APPLICATIONS:Military Hunting Wildlife observation Surveillance Security Navigation Hidden-object detection Entertainment
Law Enforcement
Military
Nature
Miscellaneous
Night Vision System in Cars
Night Vision makes a vehicles darkened surrounding visible out
to a distance of 150 meters. Night Vision generates an electronically processed video image that can be displayed in real time in the head-up display.
ConclusionIts a critical study, which plays a vital role in modern world as it is involved with advance use of science and technology.
The advances in technology have created the tremendousopportunities for Vision System and Image Processing. The technology has evolved greatly since their introduction, leading to several generation of night vision equipment with performance increasing and price decreasing.
From the above discussion we can conclude that this field hasrelatively more advantages and disadvantages and hence is very useful in varied branches.
References [1] IEEE TRANSACTIONS ON INTELLIGENT TRANSPORTATION SYSTEMS, VOL. 3, NO. 3, SEPTEMBER 2002, Development of Night-Vision System Takayuki Tsuji, Hiroshi Hattori, Masahito Watanabe, and Nobuharu Nagaoka http://electronics.howstuffworks.com/nightvision3.ht ml http://www.nightvision.com/military/militaryhome.h tml http://www.morovision.com/hownightvisionworks.ht m