Atoms
Atoms are constantly in motion. They continuously vibrate, move and rotate. Even the atoms that make up the chairs that we sit in are moving around. Solids are actually in motion! Atoms can be in different states of excitation. In other words, they can have different energies. If we apply a lot of energy to an atom, it can leave what is called the ground-state energy level and move to an excited level. The level of excitation depends on the amount of energy applied to the atom via heat, light or electricity.
Types Of Thermal Imaging Devices
Most thermal-imaging devices scan at a rate of 30 times per second. They can sense temperatures ranging from -4 degrees Fahrenheit (-20 degrees Celsius) to 3,600 F (2,000 C), and can normally detect changes in temperature of about 0.4 F (0.2 C).
Introduction
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. 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
Image enhancement technique is used in night vision technology. In fact, image-enhancement systems are normally called night-vision devices (NVDs). NVDs rely on a special tube, called an image-intensifier tube, to collect and amplify infrared and visible light.
ABSTRACT
Night vision is used to locate an object which is 200 yards away even in moonless, cloudy night. Night vision can work into two different ways, depending on the technology used .They are image enhancement and thermal imaging. Image enhancement works by collecting lower portion of infrared light spectrum. Thermal imaging operates by capturing the upper portion of the infrared light spectrum .
Enhanced Spectral Range
Enhanced spectral range techniques make the viewer sensitive to types of light that would be 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 UV radiation).
Performance Attributes
There are three important attributes for judging performance. They are: sensitivity, signal and resolution. As the customer, you need to know about these three characteristics to determine the performance level of a night vision system.
Sensitivity, or photo response, is the image tube's ability to detect available light. It is usually measured in "uA/lm," or microamperes per lumen. ITT's advanced technology and processing enable us to give our customers products with outstanding sensitivity.
Conclusion
Night vision is used to locate an object which is 200 yards away even in moonless , cloudy night .The original purpose of night vision was to locate enemy targets at night.
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