04-12-2012, 03:52 PM
NIGHT VISION TECHNOLOGY
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ABSTRACT
Most of us instinctively think of darkness as a cloak; a way to hide. So, how can you see someone standing more than 200 yards away on a black-pitch night? But this technology of NIGHT VISION makes it possible to view even distant objects at night times, with proper equipment. By this security forces can keep watch on terrorists who sneak into a country at night times.
In this presentation, a brief description is given about Night Vision technology, its equipments and its applications.
INTRODUTION:
The first thing you probably think of when you see the words night vision is a spy or action movie you've seen, in which someone straps on a pair of night-vision goggles to find someone else in a dark building on a moonless night. And you may have wondered "Do those things really work? Can you actually see in the dark?"
The answer is most definitely yes. With the proper night-vision equipment, you can see a person standing over 200 yards (183 m) away on a moonless, cloudy night! Night vision can work in two very different ways, depending on the technology used.
• Image enhancement - This works by collecting the tiny amounts of light, including the lower portion of the infrared light spectrum, that are present but may be imperceptible to our eyes, and amplifying it to the point that we can easily observe the image.
• Thermal imaging - This technology operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings.
In this article, you will learn about the two major night-vision technologies. We'll also discuss the various types of night-vision equipment and applications. But first, let's talk about infrared light.
Infrared Light
In order to understand night vision, it is important to understand something about light. 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.
Thermal Imaging
Here's how thermal imaging works:
1. A special lens focuses the infrared light emitted by all of the objects in view.
2. 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. It only takes about one-thirtieth of a second for the detector array to obtain the temperature information to make the thermogram. This information is obtained from several thousand points in the field of view of the detector array.
3. The thermogram created by the detector elements is translated into electric impulses.
4. The impulses are sent to a signal-processing unit, a circuit board with a dedicated chip that translates the information from the elements into data for the display.
CONCLUSION:
In this terror stricken world it is very essential to protect one’s country. Night Vision is helpful to secure the country at the night times and to discover the Hidden objects. It is also used for Wild life observation. This technology is booming all over the world, even in India at present. Still research is going on to make it more effective and better.