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Infrared IR Night Vision - How it works - Made Easy {101}

A good place to enter the world of night vision is through infrared. Its low cost and readily available. So what is it? Glad you asked. Infrared's a form of energy, and part of the electromagnetic spectrum. Infrared falls between microwaves and visible light because its waves are shorter than microwaves but longer than visible light. Just like with visible light, there's a range that can be divided. Infrared is divided into three sections based on the wave length. These groups are commonly known as near (which is what most of our illuminated night vision falls under), medium and far (which is what most thermal vision devices fall under). Near infrared is nearest to the visible light side of the spectrum, but still falls within a range thats not noticeable to people or game.

Image Intensifying

Active illumination couples imaging intensification with an active source of illumination in the near spectral range of 700–1,000 nm, just below the visible spectrum of the human eye. Ambient light converts photons into electrons, and is amplified by a chemical and electrical process that then converts it back into visible light where a gray or green monochrome image on a optic display is seen. It doesn't need much reflective light, moon light in the sky is enough. Because active infrared night vision systems can incorporate illuminators that produce high levels of infrared light, the resulting images can be higher in resolution in very low light settings. Image intensifying night vision like the Firefield in this picture, is the most common affordable night imaging system.

Thermal vision

Thermal imaging an excellent night vision option. It detects radiation in the infrared range of the electromagnetic spectrum at roughly 900–14,000 nm and is considered far infrared. Everything emits Infrared energy. Infrared light from the sun makes up for almost 50% of the earths heating. At night trees and vegetation diverge from the surrounding ambient temperatures making it possible for thermal infrared sensors to detect thermal radiation, and distinguish slight changes in heat signature to produce an optical image. Unlike a reflective IR device, thermal imaging doesn't need a source of illumination or any light to produce an image on the darkest of nights. The ATN scope in the picture gives a visual of a thermal image.