Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Night-vision device
Summary
A night-vision device (NVD), also known as a night optical/observation device (NOD), night-vision goggle (NVG), is an optoelectronic device that allows visualization of images in low levels of light, improving the user's night vision. The device enhances ambient visible light and converts near-infrared light into visible light which can be seen by the user; this is known as I2 (). By comparison, viewing of infrared thermal radiation is referred to as thermal imaging and operates in a different section of the infrared spectrum. A night vision device usually consists of an tube, a protective housing, and may have some type of mounting system. Many NVDs also include a protective sacrificial lens, mounted over the front lens (ie. objective lens) on NVDs to protect the latter from damage by environmental hazards and some can incorporate telescopic lenses. The image produced by an NVD is typically monochrome green, as green was considered to be the easiest color to look at for prolonged periods in the dark. Night vision devices may be passive, relying solely on ambient light, or may be active, using an IR (infrared) illuminator to better visualize the environment.
Night vision devices can be handheld but many are head-mounted and attach to helmets. When used with firearms, an IR laser sight is often mounted to the user's weapon. The laser sight produces an infrared beam that is only visible through an NVD and aids with aiming. Some night vision devices are specially made to be mounted to firearms. These can used in conjunction with weapon sights like rifle scopes or can be used as standalone sights; some thermal weapon sights have been designed to provide similar capabilities.
These devices were first used in World War II and came into wide use during the Vietnam War. The technology has evolved greatly since its introduction, leading to several "generations" of night-vision equipment with performance increases and price reductions.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Related concepts (12)
Telescopic sight
A telescopic sight, commonly called a scope informally, is an optical sighting device based on a refracting telescope. It is equipped with some form of a referencing pattern – known as a reticle – mounted in a focally appropriate position in its optical system to provide an accurate point of aim. Telescopic sights are used with all types of systems that require magnification in addition to reliable visual aiming, as opposed to non-magnifying iron sights, reflector (reflex) sights, holographic sights or laser sights, and are most commonly found on long-barrel firearms, particularly rifles, usually via a scope mount.
Night vision
Night vision is the ability to see in low-light conditions, either naturally with scotopic vision or through a night-vision device. Night vision requires both sufficient spectral range and sufficient intensity range. Humans have poor night vision compared to many animals such as cats, foxes and rabbits, in part because the human eye lacks a tapetum lucidum, tissue behind the retina that reflects light back through the retina thus increasing the light available to the photoreceptors.
Reticle
A reticle, or reticule also known as a graticule, is a pattern of fine lines or markings built into the eyepiece of an optical device such as a telescopic sight, spotting scope, theodolite, optical microscope or the screen of an oscilloscope, to provide measurement references during visual inspections. Today, engraved lines or embedded fibers may be replaced by a superimposed on a screen or eyepiece.