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Two American soldiers pictured during the 2003 Iraq War seen through an Image Intensifier

Night vision is the ability to see in a dark environment. Whether by biological or technological means, night vision is made possible by a combination of two approaches: enhanced spectral range, and enhanced intensity range. Image File history File links Information. ... Image File history File links Circle-question. ... Image File history File links Nightvision. ... Image File history File links Nightvision. ... For other uses of the term, see Iraq war (disambiguation) The 2003 invasion of Iraq (also called the 2nd or 3rd Persian Gulf War) began on March 20, 2003, when forces belonging primarily to the United States and the United Kingdom invaded Iraq without the explicit backing of the United... Darkness is the absence of light. ...

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). Night vision can work in two very different ways, depending on the technology used. Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... “UV” redirects here. ...

1. 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.
2. 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.

Enhanced intensity range

Enhanced intensity range is simply the ability to see with very small quantities of light. Although the human visual system can, in theory, detect single photons under ideal conditions, the neurological noise filters limit sensitivity to a few tens of photons, even in ideal conditions [1]. Some animals have evolved better night vision through the use of a larger optical aperture, improved retina composition that can detect weaker light over a larger spectral range, more photoefficient optics in the eye, and improved neurological filtering which is more tolerant of noise. Enhanced intensity range is achieved via technological means through the use of an image intensifier, gain multiplication CCD, or other very low-noise and high-sensitivity array of photodetectors. In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... For the Irish mythological figure, see Naoise. ... This article is about evolution in biology. ... a big (1) and a small (2) aperture For other uses, see Aperture (disambiguation). ... Human eye cross-sectional view. ... This article does not cite any references or sources. ... Photosensors or photodetectors appear in several varieties: Photoresistors or Light Dependant Resistors (LDR) which change resistance when illuminated Photovoltaic cells or solar cells which produce a voltage and supply an electric current when illuminated Photodiodes which can operate in photovoltaic mode or photoconductive mode Phototubes containing a photocathode which emits...

Biological night vision

In biological night vision, molecules of rhodopsin in the rods of the eye undergo a change in shape as light is absorbed by them. Rhodopsin is the chemical that allows night-vision, and is extremely sensitive to light. Exposed to white light, the pigment immediately bleaches, and it takes about 30 minutes to regenerate fully, but most of the adaptation occurs within the first five or ten minutes in the dark. Rhodopsin in the human rods is insensitive to the longer red wavelengths of light, so many people use red light to preserve night vision as it will not deplete the eye's rhodopsin stores in the rods and instead is viewed by the cones. A rhodopsin molecule (yellow) with bound retinal (orange), embedded in a cell membrane (lipids shown as green, head groups as red/blue). ... A human eye Eyes are organs of vision that detect light. ... The wavelength is the distance between repeating units of a wave pattern. ... Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of photoreceptor, cone cells. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina of the eye which only function in relatively bright light. ...

Some animals, such as cats, dogs, and deer have a structure called tapetum lucidum in the back of the eye that reflects light back towards the retina, increasing the amount of light it captures. In humans, only 10% of the light that enters the eye falls on photosensitive parts of the retina. An animal's ability to see in low light levels may be similar to what humans see when using first or perhaps second generation image intensifiers. Binomial name Felis catus Linnaeus, 1758 Synonyms Felis lybica invalid junior synonym The cat (or domestic cat, house cat) is a small carnivorous mammal. ... Trinomial name Canis lupus familiaris The dog (Canis lupus familiaris) is a domestic subspecies of the wolf, a mammal of the Canidae family of the order Carnivora. ... “Fawn” redirects here. ... Tapetum lucidum in a calf eye, with the retina hanging down. ... A human eye Eyes are organs of vision that detect light. ... Human eye cross-sectional view. ... Human eye cross-sectional view. ... This article does not cite any references or sources. ...

Night glasses

Night glasses are telescopes or binoculars with a large diameter objective. Large lenses can gather and concentrate light, thus intensifying light with purely optical means and enabling the user to see better in the dark than with naked eye alone. Often night glasses also have a fairly large exit pupil of 7 mm or more to let all gathered light into the user's eye. However, many people can't take advantage of this because of the limited dilation of the human pupil. To overcome this, soldiers were sometimes issued atropine eye drops to dilate pupils. Before the introduction of image intensifiers, night glasses were the only method of night vision, and thus were widely utilized, especially at sea. Second World War era night glasses usually had a lens diameter of 56 mm or more with magnification of seven or eight. Major drawbacks of night glasses are their large size and weight. This article does not cite any references or sources. ... Porro-prism binoculars with central focusing Binocular telescopes, or binoculars, (also known as field glasses) are two identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects. ... The exit pupil is a concept in optics, and is defined as the minimum diameter of the light beam leaving an eyepiece though which all of the light from the eyepiece passes. ... The human eye The pupil is the central transparent area (showing as black). ... Atropine is a tropane alkaloid extracted from the deadly nightshade (Atropa belladonna) and other plants of the family Solanaceae. ...

Thermal vision

For infrared, or thermal, sensing is generally not considered night vision because it is constructed with mechanisms substantially different from the methods used to sense visible light. It is possible to construct an imaging device with microwave energy, sound, or any other signal that is reflected or radiated by objects and can be focused and sensed, but these are also not generally considered night vision. Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... Microwaves are electromagnetic waves with wavelengths longer than those of terahertz (THz) frequencies, but relatively short for radio waves. ... Sound is a disturbance of mechanical energy that propagates through matter as a wave. ...

Some animals have the ability to sense far infrared energy which we perceive as heat. This is prevalent in some snakes such as pit vipers and boas. However, this is not actual "vision", but more of a system of thermosensitive pits in the face that can detect the amount of heat and the distance to the heat source. There is still some debate as to what degree this information is perceived as "feeling" heat, and to what degree it is processed as an image by the snake's brain. Since these sense structures lack imaging optics, the spatial sensory perception resolution is considered very poor. Families Acrochordidae Aniliidae Anomalepididae Anomochilidae Atractaspididae Boidae Bolyeriidae Colubridae Cylindrophiidae Elapidae Hydrophiidae Leptotyphlopidae Loxocemidae Pythonidae Tropidophiidae Typhlopidae Uropeltidae Viperidae Xenopeltidae Snakes are cold blooded legless reptiles closely related to lizards, which share the order Squamata. ... {{Taxobox[[{| class=wikitable |- ]]</nowiki>]] --> </gallery> |} |}]]| [[Image:[[Media:Failed to parse (unknown error): == <nowiki>#REDIRECT [[<sup><small>[ == == == [[Image:[[Image:[[Media:[[Media:#REDIRECT [[#REDIRECT [[#REDIRECT [[ ---- ---- <math><math><math>[[Media:[[Media: == == == == == == [[[[[[color = pink]]]]]] == == == == == ==]]]] </math></math>]]]]]]]]]]]]]] == == ==]]]</nowiki> ==</math>]]]] | name = Crotalinae | image = TimberRattler. ... Species Boa Constrictor Acrantophis dumerili Acrantophis madagascariensis Sanzinia madagascariensis Boa is a genus of snakes in the family Boidae. ...

See Thermographic camera. Image of a small dog taken in mid-infrared (thermal) light (false-color). ...

Image intensifier

Main article: Image intensifier

A photograph taken with a night vision camera

The image intensifier is a vacuum-tube based device that converts visible light from an image so that a dimly lit scene can be viewed by a camera or the naked eye. While many believe the light is "amplified," it is not. When IR light strikes a charged photocathode plate electrons are emitted through a vacuum tube that strike the microchannel plate that cause the image screen to illuminate with a picture in the same pattern as the IR light that strikes the photocathode, and is on a frequency that the human eye can see. This is much like a CRT television, but instead of color guns the photocathode does the emitting. The image is said to become "intensified" because the output visible light is brighter than the incoming IR light, and this effect directly relates to the difference in passive and active night vision goggles. Currently, the most popular image intensifier is the drop-in ANVIS module. This article does not cite any references or sources. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... In an electron tube, a negatively charged electrode coated with a photosensitive compound. ... CRT can mean: Cathode Ray Tube, in electronics, a display device (such as those used in one type of television) C Run-Time, in computing Charitable Remainder Trust, in Law Chinese Remainder Theorem, in mathematics Corneal Refractive Therapy, in medicine Criterion-referenced test, in U.S. schools Critical race theory... Experimental night vision goggles. ...

Night vision devices

Main article: Night vision device

A night vision device (NVD) is a device comprising an IR image intensifier tube in a rigid casing, commonly used by military forces. A specific type of NVD, the night vision goggle, or NVG is a night vision device with dual eyepieces; the device can utilize either one intensifier tube with the same image sent to both eyes, or a separate image intensifier tube for each eye. Other types include monocular night vision devices with only one eyepiece which may be mounted to firearms as night sights. It has been suggested that this article or section be merged with Image intensifier. ... Armed forces are the military forces of a state. ...

See also

• Thermographic camera
• Image intensifier
• Scotopic vision
• Night vision goggles

Image of a small dog taken in mid-infrared (thermal) light (false-color). ... This article does not cite any references or sources. ... Scotopic vision is the monochromatic vision of the eye in dim light. ... Experimental night vision goggles. ...

Patents

• US D248860 - Night vision Pocketscope 

• US 4707595 - Invisible light beam projector and night vision system 

• US 4991183 - Target illuminators and systems employing same 

• US 6075644 - Panoramic night vision goggles 

World Manufacturers of Night Vision Devices

• Aiptek Taiwan
• American Technologies Network Corporation (ATN) USA
• Bushnell USA
• EG&G USA
• Hensoldt-Zeiss Germany (now Carl Zeiss Optronics GmbH)
• ITT Corporation USA (have acquired Litton)
• Kongsberg Gruppen Norway (have acquired Simrad)
• Photonis Europe
• Raytheon USA
• Thales Group France
• Yukon Russia

Aiptek logo Advanced Intelligent Personal Technologies (AIPTEK) is a firm that produces digital equipment. ... The subject of this article may not satisfy the notability guideline or one of the following guidelines for inclusion on Wikipedia: Biographies, Books, Companies, Fiction, Music, Neologisms, Numbers, Web content, or several proposals for new guidelines. ... Bushnell may refer to: Bushnell, Florida Bushnell, South Dakota Bushnell, Nebraska Bushnell, Illinois This is a disambiguation page &#8212; a navigational aid which lists other pages that might otherwise share the same title. ... EG&G logo EG&G is a defense contractor and provider of management and technical services. ... Carl Zeiss in middle age. ... ITT Corporation, NYSE: ITT is a large American manufacturing company with 2006 revenues of $7. ... Kongsberg Gruppen (KOG) (lit. ... Raytheon Company (NYSE: RTN) is a major United States military contractor based in Waltham, Massachusetts. ... The Thales Group (Euronext: HO) is a global electronics company serving aerospace, defence, and information technology markets worldwide. ...

External links

• Night Vision & Electronic Sensors Directorate - Fort Belvoir, Virginia

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Night Vision