» 
Arabic Bulgarian Chinese Croatian Czech Danish Dutch English Estonian Finnish French German Greek Hebrew Hindi Hungarian Icelandic Indonesian Italian Japanese Korean Latvian Lithuanian Malagasy Norwegian Persian Polish Portuguese Romanian Russian Serbian Slovak Slovenian Spanish Swedish Thai Turkish Vietnamese
Arabic Bulgarian Chinese Croatian Czech Danish Dutch English Estonian Finnish French German Greek Hebrew Hindi Hungarian Icelandic Indonesian Italian Japanese Korean Latvian Lithuanian Malagasy Norwegian Persian Polish Portuguese Romanian Russian Serbian Slovak Slovenian Spanish Swedish Thai Turkish Vietnamese

definitions - Infrared

infrared (adj.)

1.having or employing wavelengths longer than light but shorter than radio waves; lying outside the visible spectrum at its red end"infrared radiation" "infrared photography"

infrared (n.)

1.the infrared region of the electromagnetic spectrum; electromagnetic wave frequencies below the visible range"they could sense radiation in the infrared"

2.electromagnetic radiation with wavelengths longer than visible light but shorter than radio waves

   Advertizing ▼

definition (more)

definition of Wikipedia

synonyms - Infrared

   Advertizing ▼

phrases

-Atmospheric Infrared Sounder • Blackbody infrared radiative dissociation • Cosmic infrared background • Diffuse Infrared Background Experiment • Digital infrared thermal imaging in health care • Directional Infrared Counter Measures • Far Infrared • Far infrared astronomy • Far-infrared laser • Fiber focus infrared soldering • Forward looking infrared • Gamma-Ray Burst Optical/Near-Infrared Detector • Gornergrat Infrared Telescope • Infrared (disambiguation) • Infrared (record label) • Infrared Data Association • Infrared Optical Telescope Array • Infrared Physics and Technology • Infrared Processing and Analysis Center • Infrared Riding Hood • Infrared Roses • Infrared Sightings • Infrared Space Observatory • Infrared Spatial Interferometer • Infrared and thermal testing • Infrared astronomy • Infrared blaster • Infrared camera • Infrared cirrus • Infrared cleaning • Infrared countermeasures • Infrared cut-off filter • Infrared detector • Infrared divergence • Infrared excess • Infrared fixed point • Infrared fluorescent protein • Infrared gas analyzer • Infrared heater • Infrared homing • Infrared lamp • Infrared mammography • Infrared multiphoton dissociation • Infrared photo • Infrared photography • Infrared point sensor • Infrared port • Infrared sauna • Infrared sensing in snakes • Infrared signature • Infrared spectroscopy • Infrared spectroscopy correlation table • Infrared telescope • Infrared telescopes • Infrared thermal microscopy • Infrared thermometer • Infrared vision • Infrared window • List of astronomical interferometers at visible and infrared wavelengths • Long-wave infrared • Luminous InfraRed Galaxies • Luminous Infrared Galaxies • Luminous infrared galaxy • Meteosat Visible and Infrared Imager • Mid-InfraRed Technologies for Health and the Environment • Mid-infrared • Mobile Infrared Transmitter • NASA Infrared Telescope Facility • Near Field Infrared Experiment • Near Infrared • Near Infrared Camera and Multi-Object Spectrometer • Near infrared spectroscopy • Near infrared spectrum • Near-infrared • Near-infrared signature management technology • Nondispersive infrared sensor • Passive infrared sensor • Quantum well infrared photodetector • RIAS (Remote Infrared Audible Signage) • SPRITE infrared detector • Space-Based Infrared System • Space-Based Infrared Systems Wing • Stratospheric Observatory for Infrared Astronomy • Television Infrared Observation Satellite • Thermal infrared spectroscopy • Two-dimensional infrared spectroscopy • UKIRT Infrared Deep Sky Survey • Ultra-Luminous InfraRed Galaxy • Ultra-Luminous infrared galaxy • Ultra-luminous InfraRed Galaxy • Ultra-luminous Infrared Galaxies • Ultra-luminous infrared galaxy • UltraLuminous InfraRed Galaxies • UltraLuminous InfraRed Galaxy • UltraLuminous infrared galaxy • Ultraluminous InfraRed Galaxy • Ultraluminous Infrared Galaxies • Ultraluminous Infrared Galaxy • Ultraluminous infrared galaxies • Ultraluminous infrared galaxy • United Kingdom Infrared Telescope • Visible and near-infrared • Wide Field Infrared Explorer • Wide-field Infrared Survey Explorer

analogical dictionary

Wikipedia

Infrared

                   
  An image of two people in mid-infrared ("thermal") light (false-color)
  This infrared space telescope image has blue, green and red corresponding to 3.4, 4.6, and 12 micron wavelengths respectively.

Infrared (IR) light is electromagnetic radiation with longer wavelengths than those of visible light, extending from the nominal red edge of the visible spectrum at 0.74 micrometres (µm) to 300 µm. This range of wavelengths corresponds to a frequency range of approximately 1 to 400 THz,[1] and includes most of the thermal radiation emitted by objects near room temperature. Infrared light is emitted or absorbed by molecules when they change their rotational-vibrational movements.

Much of the energy from the Sun arrives on Earth in the form of infrared radiation. Sunlight at zenith provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, and 32 watts is ultraviolet radiation.[2] The balance between absorbed and emitted infrared radiation has a critical effect on the Earth's climate.

Infrared light is used in industrial, scientific, and medical applications. Night-vision devices using infrared illumination allow people or animals to be observed without the observer being detected. In astronomy, imaging at infrared wavelengths allows observation of objects obscured by interstellar dust. Infrared imaging cameras are used to detect heat loss in insulated systems, observe changing blood flow in the skin, and overheating of electrical apparatus.

Light Comparison[3]
Name Wavelength Frequency (Hz) Photon Energy (eV)
Gamma ray less than 0.01 nm more than 10 EHZ 100 keV - 300+ GeV
X-Ray 0.01 nm to 10 nm 30 EHz - 30 PHZ 120 eV to 120 keV
Ultraviolet 10 nm - 390 nm 30 PHZ - 790 THz 3 eV to 124 eV
Visible 390 - 750 nm 790 THz - 405 THz 1.7 eV - 3.3 eV
Infrared 750 nm - 1 mm 405 THz - 300 GHz 1.24 meV - 1.7 eV
Microwave 1 mm - 1 meter 300 GHz - 300 MHz 1.24 µeV - 1.24 meV
Radio 1 mm - 100,000 km 300 GHz - 3 Hz 12.4 feV - 1.24 meV

Infrared imaging is used extensively for military and civilian purposes. Military applications include target acquisition, surveillance, night vision, homing and tracking. Non-military uses include thermal efficiency analysis, environmental monitoring, industrial facility inspections, remote temperature sensing, short-ranged wireless communication, spectroscopy, and weather forecasting. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space, such as molecular clouds; detect objects such as planets, and to view highly red-shifted objects from the early days of the universe.[4]

Humans at normal body temperature radiate chiefly at wavelengths around 12 μm (micrometers), as shown by Wien's displacement law.

At the atomic level, infrared energy elicits vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines absorption and transmission of photons in the infrared energy range, based on their frequency and intensity.[5]

Contents

  Different regions in the infrared

Objects generally emit infrared radiation across a spectrum of wavelengths, but sometimes only a limited region of the spectrum is of interest because sensors usually collect radiation only within a specific bandwidth. Therefore, the infrared band is often subdivided into smaller sections.

  Commonly used sub-division scheme

A commonly used sub-division scheme is:[6]

Division Name Abbreviation Wavelength Photon Energy Characteristics
Near-infrared NIR, IR-A DIN 0.75-1.4 µm 0.9-1.7 eV Defined by the water absorption, and commonly used in fiber optic telecommunication because of low attenuation losses in the SiO2 glass (silica) medium. Image intensifiers are sensitive to this area of the spectrum. Examples include night vision devices such as night vision goggles.
Short-wavelength infrared SWIR, IR-B DIN 1.4-3 µm 0.4-0.9 eV Water absorption increases significantly at 1,450 nm. The 1,530 to 1,560 nm range is the dominant spectral region for long-distance telecommunications.
Mid-wavelength infrared MWIR, IR-C DIN. Also called intermediate infrared (IIR) 3-8 µm 150-400 meV In guided missile technology the 3-5 µm portion of this band is the atmospheric window in which the homing heads of passive IR 'heat seeking' missiles are designed to work, homing on to the Infrared signature of the target aircraft, typically the jet engine exhaust plume
Long-wavelength infrared LWIR, IR-C DIN 8–15 µm 80-150 meV This is the "thermal imaging" region, in which sensors can obtain a completely passive picture of the outside world based on thermal emissions only and requiring no external light or thermal source such as the sun, moon or infrared illuminator. Forward-looking infrared (FLIR) systems use this area of the spectrum. This region is also called the "thermal infrared."
Far infrared FIR 15 - 1,000 µm 1.2-80 meV (see also far-infrared laser).

NIR and SWIR is sometimes called "reflected infrared" while MWIR and LWIR is sometimes referred to as "thermal infrared." Due to the nature of the blackbody radiation curves, typical 'hot' objects, such as exhaust pipes, often appear brighter in the MW compared to the same object viewed in the LW.

  CIE division scheme

The International Commission on Illumination (CIE) recommended the division of infrared radiation into the following three bands:[7]

  • IR-A: 700 nm–1400 nm (0.7 µm – 1.4 µm, 215 THz - 430 THz)
  • IR-B: 1400 nm–3000 nm (1.4 µm – 3 µm, 100 THz - 215 THz)
  • IR-C: 3000 nm–1 mm (3 µm – 1000 µm, 300 GHz - 100 THz)

  ISO 20473 scheme

ISO 20473 specifies the following scheme:[8]

Designation Abbreviation Wavelength
Near Infrared NIR 0.78–3 µm
Mid Infrared MIR 3–50 µm
Far Infrared FIR 50–1000 µm

  Astronomy division scheme

Astronomers typically divide the infrared spectrum as follows:[9]

Designation Abbreviation Wavelength
Near Infrared NIR (0.7–1) to 5 µm
Mid Infrared MIR 5 to (25–40) µm
Far Infrared FIR (25–40) to (200–350) µm.

These divisions are not precise and can vary depending on the publication. The three regions are used for observation of different temperature ranges, and hence different environments in space.

  Sensor response division scheme

  Plot of atmospheric transmittance in part of the infrared region.

A third scheme divides up the band based on the response of various detectors:[10]

  • Near infrared: from 0.7 to 1.0  µm (from the approximate end of the response of the human eye to that of silicon).
  • Short-wave infrared: 1.0 to 3  µm (from the cut off of silicon to that of the MWIR atmospheric window. InGaAs covers to about 1.8  µm; the less sensitive lead salts cover this region.
  • Mid-wave infrared: 3 to 5  µm (defined by the atmospheric window and covered by Indium antimonide [InSb] and HgCdTe and partially by lead selenide [PbSe]).
  • Long-wave infrared: 8 to 12, or 7 to 14  µm: the atmospheric window (Covered by HgCdTe and microbolometers).
  • Very-long wave infrared (VLWIR): 12 to about 30  µm, covered by doped silicon.

These divisions are justified by the different human response to this radiation: near infrared is the region closest in wavelength to the radiation detectable by the human eye, mid and far infrared are progressively further from the visible spectrum. Other definitions follow different physical mechanisms (emission peaks, vs. bands, water absorption) and the newest follow technical reasons (The common silicon detectors are sensitive to about 1,050 nm, while InGaAs' sensitivity starts around 950 nm and ends between 1,700 and 2,600 nm, depending on the specific configuration). Unfortunately, international standards for these specifications are not currently available.

The boundary between visible and infrared light is not precisely defined. The human eye is markedly less sensitive to light above 700 nm wavelength, so longer wavelengths make insignificant contributions to scenes illuminated by common light sources. But particularly intense light (e.g., from IR lasers, or from bright daylight with the visible light removed by colored gels) can be detected up to approximately 780 nm, and will be perceived as red light, although sources of up to 1050 nm can be seen as a dull red glow in intense sources.[11] The onset of infrared is defined (according to different standards) at various values typically between 700 nm and 800 nm.

  Telecommunication bands in the infrared

In optical communications, the part of the infrared spectrum that is used is divided into seven bands based on availability of light sources transmitting/absorbing materials (fibers) and detectors:[12]

Band Descriptor Wavelength range
O band Original 1260–1360 nm
E band Extended 1360–1460 nm
S band Short wavelength 1460–1530 nm
C band Conventional 1530–1565 nm
L band Long wavelength 1565–1625 nm
U band Ultralong wavelength 1625–1675 nm

The C-band is the dominant band for long-distance telecommunication networks. The S and L bands are based on less well established technology, and are not as widely deployed.

  Heat

Infrared radiation is popularly known as "heat radiation", but light and electromagnetic waves of any frequency will heat surfaces that absorb them. Infrared light from the Sun only accounts for 49%[13] of the heating of the Earth, with the rest being caused by visible light that is absorbed then re-radiated at longer wavelengths. Visible light or ultraviolet-emitting lasers can char paper and incandescently hot objects emit visible radiation. Objects at room temperature will emit radiation mostly concentrated in the 8 to 25 µm band, but this is not distinct from the emission of visible light by incandescent objects and ultraviolet by even hotter objects (see black body and Wien's displacement law).[14]

Heat is energy in transient form that flows due to temperature difference. Unlike heat transmitted by thermal conduction or thermal convection, radiation can propagate through a vacuum.

The concept of emissivity is important in understanding the infrared emissions of objects. This is a property of a surface which describes how its thermal emissions deviate from the ideal of a black body. To further explain, two objects at the same physical temperature will not "appear" the same temperature in an infrared image if they have differing emissivities.

  Applications

  Night vision

  Active-infrared night vision : the camera illuminates the scene at infrared wavelengths invisible to the human eye. Despite a dark back-lit scene, active-infrared night vision delivers identifying details, as seen on the display monitor.

Infrared is used in night vision equipment when there is insufficient visible light to see.[15] Night vision devices operate through a process involving the conversion of ambient light photons into electrons which are then amplified by a chemical and electrical process and then converted back into visible light.[15] Infrared light sources can be used to augment the available ambient light for conversion by night vision devices, increasing in-the-dark visibility without actually using a visible light source.[15]

The use of infrared light and night vision devices should not be confused with thermal imaging which creates images based on differences in surface temperature by detecting infrared radiation (heat) that emanates from objects and their surrounding environment.[16]

  Thermography

  A thermographic image of a dog

Infrared radiation can be used to remotely determine the temperature of objects (if the emissivity is known). This is termed thermography, or in the case of very hot objects in the NIR or visible it is termed pyrometry. Thermography (thermal imaging) is mainly used in military and industrial applications but the technology is reaching the public market in the form of infrared cameras on cars due to the massively reduced production costs.

Thermographic cameras detect radiation in the infrared range of the electromagnetic spectrum (roughly 900–14,000 nanometers or 0.9–14 μm) and produce images of that radiation. Since infrared radiation is emitted by all objects based on their temperatures, according to the black body radiation law, thermography makes it possible to "see" one's environment with or without visible illumination. The amount of radiation emitted by an object increases with temperature, therefore thermography allows one to see variations in temperature (hence the name).

  Hyperspectral imaging

  Hyperspectral thermal infrared emission measurement, an outdoor scan in winter conditions, ambient temperature -15°C, image produced with a Specim LWIR hyperspectral imager. Relative radiance spectra from various targets in the image are shown with arrows. The infrared spectra of the different objects such as the watch clasp have clearly distinctive characteristics. The contrast level indicates the temperature of the object.[17]
  Infrared light from the LED of an Xbox 360 remote control as seen by a digital camera.

A hyperspectral image, a basis for chemical imaging, is a "picture" containing continuous spectrum through a wide spectral range. Hyperspectral imaging is gaining importance in the applied spectroscopy particularly in the fields of NIR, SWIR, MWIR, and LWIR spectral regions. Typical applications include biological, mineralogical, defence, and industrial measurements.

Thermal Infrared Hyperspectral Camera can be applied similarly to a Thermographic camera, with the fundamental difference that each pixel contains a full LWIR spectrum. Consequently, chemical identification of the object can be performed without a need for an external light source such as the Sun or the Moon. Such cameras are typically applied for geological measurements, outdoor surveillance and UAV applications.[18]

  Other imaging

In infrared photography, infrared filters are used to capture the near-infrared spectrum. Digital cameras often use infrared blockers. Cheaper digital cameras and camera phones have less effective filters and can "see" intense near-infrared, appearing as a bright purple-white color. This is especially pronounced when taking pictures of subjects near IR-bright areas (such as near a lamp), where the resulting infrared interference can wash out the image. There is also a technique called 'T-ray' imaging, which is imaging using far-infrared or terahertz radiation. Lack of bright sources makes terahertz photography technically more challenging than most other infrared imaging techniques. Recently T-ray imaging has been of considerable interest due to a number of new developments such as terahertz time-domain spectroscopy.

  Tracking

Infrared tracking, also known as infrared homing, refers to a passive missile guidance system which uses the emission from a target of electromagnetic radiation in the infrared part of the spectrum to track it. Missiles which use infrared seeking are often referred to as "heat-seekers", since infrared (IR) is just below the visible spectrum of light in frequency and is radiated strongly by hot bodies. Many objects such as people, vehicle engines, and aircraft generate and retain heat, and as such, are especially visible in the infrared wavelengths of light compared to objects in the background.[19]

  Heating

Infrared radiation can be used as a deliberate heating source. For example it is used in infrared saunas to heat the occupants, and also to remove ice from the wings of aircraft (de-icing). Far infrared is also gaining popularity as a safe heat therapy method of natural health care and physiotherapy. Infrared can be used in cooking and heating food as it predominantly heats the opaque, absorbent objects, rather than the air around them.

Infrared heating is also becoming more popular in industrial manufacturing processes, e.g. curing of coatings, forming of plastics, annealing, plastic welding, print drying. In these applications, infrared heaters replace convection ovens and contact heating.

Infrared heaters] produce heat that is a product of invisible light and they consist of three parts: infrared light bulbs, a heat exchanger and a fan that blows air onto the exchanger to disperse the heat.

Efficiency is achieved by matching the wavelength of the infrared heater to the absorption characteristics of the material.

  Communications

IR data transmission is also employed in short-range communication among computer peripherals and personal digital assistants. These devices usually conform to standards published by IrDA, the Infrared Data Association. Remote controls and IrDA devices use infrared light-emitting diodes (LEDs) to emit infrared radiation which is focused by a plastic lens into a narrow beam. The beam is modulated, i.e. switched on and off, to encode the data. The receiver uses a silicon photodiode to convert the infrared radiation to an electric current. It responds only to the rapidly pulsing signal created by the transmitter, and filters out slowly changing infrared radiation from ambient light. Infrared communications are useful for indoor use in areas of high population density. IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for remote controls to command appliances. Infrared remote control protocols like RC-5, SIRC, are used to communicate with infrared.

Free space optical communication using infrared lasers can be a relatively inexpensive way to install a communications link in an urban area operating at up to 4 gigabit/s, compared to the cost of burying fiber optic cable.

Infrared lasers are used to provide the light for optical fiber communications systems. Infrared light with a wavelength around 1,330 nm (least dispersion) or 1,550 nm (best transmission) are the best choices for standard silica fibers.

IR data transmission of encoded audio versions of printed signs is being researched as an aid for visually impaired people through the RIAS (Remote Infrared Audible Signage) project.

  Spectroscopy

Infrared vibrational spectroscopy (see also near infrared spectroscopy) is a technique which can be used to identify molecules by analysis of their constituent bonds. Each chemical bond in a molecule vibrates at a frequency which is characteristic of that bond. A group of atoms in a molecule (e.g. CH2) may have multiple modes of oscillation caused by the stretching and bending motions of the group as a whole. If an oscillation leads to a change in dipole in the molecule, then it will absorb a photon which has the same frequency. The vibrational frequencies of most molecules correspond to the frequencies of infrared light. Typically, the technique is used to study organic compounds using light radiation from 4000–400 cm−1, the mid-infrared. A spectrum of all the frequencies of absorption in a sample is recorded. This can be used to gain information about the sample composition in terms of chemical groups present and also its purity (for example a wet sample will show a broad O-H absorption around 3200 cm−1).

  Meteorology

  IR Satellite picture taken 1315 Z on 15th October 2006. A frontal system can be seen in the Gulf of Mexico with embedded Cumulonimbus cloud. Shallower Cumulus and Stratocumulus can be seen off the Eastern Seaboard.

Weather satellites equipped with scanning radiometers produce thermal or infrared images which can then enable a trained analyst to determine cloud heights and types, to calculate land and surface water temperatures, and to locate ocean surface features. The scanning is typically in the range 10.3-12.5 µm (IR4 and IR5 channels).

High, cold ice clouds such as Cirrus or Cumulonimbus show up bright white, lower warmer clouds such as Stratus or Stratocumulus show up as grey with intermediate clouds shaded accordingly. Hot land surfaces will show up as dark grey or black. One disadvantage of infrared imagery is that low cloud such as stratus or fog can be a similar temperature to the surrounding land or sea surface and does not show up. However, using the difference in brightness of the IR4 channel (10.3-11.5 µm) and the near-infrared channel (1.58-1.64 µm), low cloud can be distinguished, producing a fog satellite picture. The main advantage of infrared is that images can be produced at night, allowing a continuous sequence of weather to be studied.

These infrared pictures can depict ocean eddies or vortices and map currents such as the Gulf Stream which are valuable to the shipping industry. Fishermen and farmers are interested in knowing land and water temperatures to protect their crops against frost or increase their catch from the sea. Even El Niño phenomena can be spotted. Using color-digitized techniques, the gray shaded thermal images can be converted to color for easier identification of desired information.

  Climatology

In the field of climatology, atmospheric infrared radiation is monitored to detect trends in the energy exchange between the earth and the atmosphere. These trends provide information on long term changes in the Earth's climate. It is one of the primary parameters studied in research into global warming together with solar radiation.

A pyrgeometer is utilized in this field of research to perform continuous outdoor measurements. This is a broadband infrared radiometer with sensitivity for infrared radiation between approximately 4.5 µm and 50 µm.

  Astronomy

  Beta Pictoris, the light blue dot off center, as seen in infrared. It combines two images, the inner disc is at 3.6 microns.
  The Spitzer Space Telescope is a dedicated infrared space observatory currently in orbit around the Sun. NASA image.

Astronomers observe objects in the infrared portion of the electromagnetic spectrum using optical components, including mirrors, lenses and solid state digital detectors. For this reason it is classified as part of optical astronomy. To form an image, the components of an infrared telescope need to be carefully shielded from heat sources, and the detectors are chilled using liquid helium.

The sensitivity of Earth-based infrared telescopes is significantly limited by water vapor in the atmosphere, which absorbs a portion of the infrared radiation arriving from space outside of selected atmospheric windows[disambiguation needed ]. This limitation can be partially alleviated by placing the telescope observatory at a high altitude, or by carrying the telescope aloft with a balloon or an aircraft. Space telescopes do not suffer from this handicap, and so outer space is considered the ideal location for infrared astronomy.

The infrared portion of the spectrum has several useful benefits for astronomers. Cold, dark molecular clouds of gas and dust in our galaxy will glow with radiated heat as they are irradiated by imbedded stars. Infrared can also be used to detect protostars before they begin to emit visible light. Stars emit a smaller portion of their energy in the infrared spectrum, so nearby cool objects such as planets can be more readily detected. (In the visible light spectrum, the glare from the star will drown out the reflected light from a planet.)

Infrared light is also useful for observing the cores of active galaxies which are often cloaked in gas and dust. Distant galaxies with a high redshift will have the peak portion of their spectrum shifted toward longer wavelengths, so they are more readily observed in the infrared.[4]

  Art history

Infrared reflectography-en.svg

Infrared reflectograms, as called by art historians,[20] are taken of paintings to reveal underlying layers, in particular the underdrawing or outline drawn by the artist as a guide. This often uses carbon black which shows up well in reflectograms, so long as it has not also been used in the ground underlying the whole painting. Art historians are looking to see if the visible layers of paint differ from the under-drawing or layers in between - such alterations are called pentimenti when made by the original artist. This is very useful information in deciding whether a painting is the prime version by the original artist or a copy, and whether it has been altered by over-enthusiastic restoration work. Generally the more pentimenti, the more likely a painting is to be the prime version. It also gives useful insights into working practices.[21]

Among many other changes in the Arnolfini Portrait of 1434 (left), the man's face was originally higher by about the height of his eye; the woman's was higher, and her eyes looked more to the front. Each of his feet was underdrawn in one position, painted in another, and then overpainted in a third. These alterations are seen in infra-red reflectograms.[22]

Similar uses of infrared are made by historians on various types of objects, especially very old written documents such as the Dead Sea Scrolls, the Roman works in the Villa of the Papyri, and the Silk Road texts found in the Dunhuang Caves.[23] Carbon black used in ink can show up extremely well.

  Biological systems

  Thermographic image of a snake eating a mouse
  Thermographic image of a fruit bat.

The pit viper has a pair of infrared sensory pits on its head. There is uncertainty regarding the exact thermal sensitivity of this biological infrared detection system.[24][25]

Other organisms that have thermoreceptive organs are pythons (family Pythonidae), some boas (family Boidae), the Common Vampire Bat (Desmodus rotundus), a variety of jewel beetles (Melanophila acuminata),[26] darkly pigmented butterflies (Pachliopta aristolochiae and Troides rhadamantus plateni), and possibly blood-sucking bugs (Triatoma infestans).[27]

  Photobiomodulation

Near infrared light, or photobiomodulation, is used for treatment of chemotherapy induced oral ulceration as well as wound healing. There is some work relating to anti herpes virus treatment.[28] Research projects include work on central nervous system healing effects via cytochrome c oxidase upregulation and other possible mechanisms.[29]

  Health hazard

Strong infrared radiation in certain industry high-heat settings may be hazard to the eyes, resulting in damage or blindness to the user. Since the radiation is invisible, special IR-proof goggles must be worn in such places.[30]

  The Earth as an infrared emitter

  Brief diagram showing the greenhouse effect

The Earth's surface and the clouds absorb visible and invisible radiation from the sun and re-emit much of the energy as infrared back to the atmosphere. Certain substances in the atmosphere, chiefly cloud droplets and water vapor, but also carbon dioxide, methane, nitrous oxide, sulfur hexafluoride, and chlorofluorocarbons,[31] absorb this infrared, and re-radiate it in all directions including back to Earth. Thus the greenhouse effect keeps the atmosphere and surface much warmer than if the infrared absorbers were absent from the atmosphere.[32]

  History of infrared science

The discovery of infrared radiation is ascribed to William Herschel, the astronomer, in the early 19th century. Herschel published his results in 1800 before the Royal Society of London. Herschel used a prism to refract light from the sun and detected the infrared, beyond the red part of the spectrum, through an increase in the temperature recorded on a thermometer. He was surprised at the result and called them "Calorific Rays". The term 'Infrared' did not appear until late in the 19th century.[33]

Other important dates include:[10]

  Infrared radiation was discovered in 1800 by William Herschel.

  See also

  References

  1. ^ Dr. S. C. Liew. "Electromagnetic Waves". Centre for Remote Imaging, Sensing and Processing. http://www.crisp.nus.edu.sg/~research/tutorial/em.htm. Retrieved 2006-10-27. 
  2. ^ "Reference Solar Spectral Irradiance: Air Mass 1.5". http://rredc.nrel.gov/solar/spectra/am1.5/. Retrieved 2009-11-12. 
  3. ^ C.R. Nave - Hyperphysics: Electromagnetic Spectrum
  4. ^ a b "IR Astronomy: Overview". NASA Infrared Astronomy and Processing Center. http://www.ipac.caltech.edu/Outreach/Edu/importance.html. Retrieved 2006-10-30. 
  5. ^ Reusch, William (1999). "Infrared Spectroscopy". Michigan State University. http://www.cem.msu.edu/~reusch/VirtualText/Spectrpy/InfraRed/infrared.htm. Retrieved 2006-10-27. 
  6. ^ Byrnes, James (2009). Unexploded Ordnance Detection and Mitigation. Springer. pp. 21–22. ISBN 978-1-4020-9252-7. 
  7. ^ Henderson, Roy. "Wavelength considerations". Instituts für Umform- und Hochleistungs. Archived from the original on 2007-10-28. http://web.archive.org/web/20071028072110/http://info.tuwien.ac.at/iflt/safety/section1/1_1_1.htm. Retrieved 2007-10-18. 
  8. ^ "ISO 20473:2007". ISO. 
  9. ^ IPAC Staff. "Near, Mid and Far-Infrared". NASA ipac. http://www.ipac.caltech.edu/Outreach/Edu/Regions/irregions.html. Retrieved 2007-04-04. 
  10. ^ a b Miller, Principles of Infrared Technology (Van Nostrand Reinhold, 1992), and Miller and Friedman, Photonic Rules of Thumb, 2004. ISBN 9780442012106[page needed]
  11. ^ D.R. Griffin, R Hubbard, G Wald (1947). "The Sensitivity of the Human Eye to Infra-Red Radiation". J. Opt. Soc. Am. 37 (7): 546–553. DOI:10.1364/JOSA.37.000546. 
  12. ^ Ramaswami, Rajiv (May 2002). "Optical Fiber Communication: From Transmission to Networking" (PDF). IEEE. http://ieeexplore.ieee.org/iel5/35/21724/01006983.pdf. Retrieved 2006-10-18. 
  13. ^ "Introduction to Solar Energy" (DOC). Passive Solar Heating & Cooling Manual. Rodale Press, Inc.. 1980. http://www.azsolarcenter.com/design/documents/passive.DOC. Retrieved 2007-08-12. 
  14. ^ McCreary, Jeremy (October 30, 2004). "Infrared (IR) basics for digital photographers-capturing the unseen (Sidebar: Black Body Radiation)". Digital Photography For What It's Worth. http://dpfwiw.com/ir.htm. Retrieved 2006-11-07. 
  15. ^ a b c "How Night Vision Works". American Technologies Network Corporation. http://www.atncorp.com/HowNightVisionWorks. Retrieved 2007-08-12. 
  16. ^ Bryant, Lynn (2007-06-11). "How does thermal imaging work? A closer look at what is behind this remarkable technology". http://www.video-surveillance-guide.com/how-does-thermal-imaging-work.htm. Retrieved 2007-08-12. 
  17. ^ Holma, H., (May 2011), Thermische Hyperspektralbildgebung im langwelligen Infrarot, Photonik
  18. ^ Frost&Sullivan, Technical Insights, Aerospace&Defence (Feb 2011): World First Thermal Hyperspectral Camera for Unmanned Aerial Vehicles
  19. ^ Mahulikar, S.P., Sonawane, H.R., & Rao, G.A.: (2007) "Infrared signature studies of aerospace vehicles", Progress in Aerospace Sciences, v. 43(7-8), pp. 218-245.
  20. ^ "IR Reflectography for Non-destructive Analysis of Underdrawings in Art Objects". Sensors Unlimited, Inc.. http://www.sensorsinc.com/artanalysis.html. Retrieved 2009-02-20. 
  21. ^ "The Mass of Saint Gregory: Examining a Painting Using Infrared Reflectography". The Cleveland Museum of Art. http://www.clevelandart.org/exhibcef/ConsExhib/html/grien.html. Retrieved 2009-02-20. 
  22. ^ National Gallery Catalogues: The Fifteenth Century Netherlandish Paintings by Lorne Campbell, 1998, ISBN 185709171[page needed]
  23. ^ "International Dunhuang Project An Introduction to digital infrared photography and its application within IDP -paper pdf 6.4 MB". Idp.bl.uk. http://idp.bl.uk/pages/technical_resources.a4d. Retrieved 2011-11-08. 
  24. ^ B. S. Jones; W. F. Lynn; M. O. Stone (2001). "Thermal Modeling of Snake Infrared Reception: Evidence for Limited Detection Range". Journal of Theoretical Biology 209 (2): 201–211. DOI:10.1006/jtbi.2000.2256. PMID 11401462. 
  25. ^ V. Gorbunov; N. Fuchigami; M. Stone; M. Grace; V. V. Tsukruk (2002). "Biological Thermal Detection: Micromechanical and Microthermal Properties of Biological Infrared Receptors". Biomacromolecules 3 (1): 106–115. DOI:10.1021/bm015591f. PMID 11866562. 
  26. ^ Evans, W.G. (1966). "Infrared receptors in Melanophila acuminata De Geer". Nature 202 (4928): 211. Bibcode 1964Natur.202..211E. DOI:10.1038/202211a0. 
  27. ^ A.L. Campbell, A.L. Naik, L. Sowards, M.O. Stone (2002). "Biological infrared imaging and sensing". Micrometre 33 (2): 211–225. DOI:10.1016/S0968-4328(01)00010-5. PMID 11567889. 
  28. ^ Hargate, G (2006). "A randomised double-blind study comparing the effect of 1072-nm light against placebo for the treatment of herpes labialis.". Clinical and experimental dermatology 31 (5): 638–41. DOI:10.1111/j.1365-2230.2006.02191.x. PMID 16780494. 
  29. ^ Desmet, KD; Paz, DA; Corry, JJ; Eells, JT; Wong-Riley, MT; Henry, MM; Buchmann, EV; Connelly, MP et al. (2006). "Clinical and experimental applications of NIR-LED photobiomodulation.". Photomedicine and laser surgery 24 (2): 121–8. DOI:10.1089/pho.2006.24.121. PMID 16706690. 
  30. ^ The artist's complete health and ... - Monona Rossol, Graphic Artists Guild (U.S.) - Google Books. Books.google.com. http://books.google.com/books?id=E7-9unTgJrwC&pg=PA33&lpg=PA33&dq=infrared+protective+goggles. Retrieved 2011-11-08. 
  31. ^ "Global Sources of Greenhouse Gases". Emissions of Greenhouse Gases in the United States 2000. Energy Information Administration. 2002-05-02. http://www.eia.doe.gov/oiaf/1605/gg01rpt/emission.html. Retrieved 2007-08-13. 
  32. ^ "Clouds & Radiation". http://earthobservatory.nasa.gov/Library/Clouds/. Retrieved 2007-08-12. 
  33. ^ "Herschel Discovers Infrared Light". Coolcosmos.ipac.caltech.edu. http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/herschel_bio.html. Retrieved 2011-11-08. 

  External links

   
               

 

All translations of Infrared


sensagent's content

  • definitions
  • synonyms
  • antonyms
  • encyclopedia

Dictionary and translator for handheld

⇨ New : sensagent is now available on your handheld

   Advertising ▼

sensagent's office

Shortkey or widget. Free.

Windows Shortkey: sensagent. Free.

Vista Widget : sensagent. Free.

Webmaster Solution

Alexandria

A windows (pop-into) of information (full-content of Sensagent) triggered by double-clicking any word on your webpage. Give contextual explanation and translation from your sites !

Try here  or   get the code

SensagentBox

With a SensagentBox, visitors to your site can access reliable information on over 5 million pages provided by Sensagent.com. Choose the design that fits your site.

Business solution

Improve your site content

Add new content to your site from Sensagent by XML.

Crawl products or adds

Get XML access to reach the best products.

Index images and define metadata

Get XML access to fix the meaning of your metadata.


Please, email us to describe your idea.

WordGame

The English word games are:
○   Anagrams
○   Wildcard, crossword
○   Lettris
○   Boggle.

Lettris

Lettris is a curious tetris-clone game where all the bricks have the same square shape but different content. Each square carries a letter. To make squares disappear and save space for other squares you have to assemble English words (left, right, up, down) from the falling squares.

boggle

Boggle gives you 3 minutes to find as many words (3 letters or more) as you can in a grid of 16 letters. You can also try the grid of 16 letters. Letters must be adjacent and longer words score better. See if you can get into the grid Hall of Fame !

English dictionary
Main references

Most English definitions are provided by WordNet .
English thesaurus is mainly derived from The Integral Dictionary (TID).
English Encyclopedia is licensed by Wikipedia (GNU).

Copyrights

The wordgames anagrams, crossword, Lettris and Boggle are provided by Memodata.
The web service Alexandria is granted from Memodata for the Ebay search.
The SensagentBox are offered by sensAgent.

Translation

Change the target language to find translations.
Tips: browse the semantic fields (see From ideas to words) in two languages to learn more.

last searches on the dictionary :

5613 online visitors

computed in 1.373s

I would like to report:
section :
a spelling or a grammatical mistake
an offensive content(racist, pornographic, injurious, etc.)
a copyright violation
an error
a missing statement
other
please precise:

Advertize

Partnership

Company informations

My account

login

registration

   Advertising ▼

Non-Contact LCD IR Laser Infrared Digital Temperature Thermometer Gun T7 (9.98 USD)

Commercial use of this term

New Non-contact IR Laser Temperature Gun Infrared Digital Thermometer Handheld (13.68 USD)

Commercial use of this term

Digital Non-Contact LCD IR Laser Nice Infrared Temperature Thermometer Gun MY8L (11.41 USD)

Commercial use of this term

Non-Contact IR Laser Temperature Gun Infrared Digital Thermometer Sight Handheld (15.95 USD)

Commercial use of this term

Temperature Gun Non-contact Infrared IR Thermometer Range -58F to 1382F w/ Laser (21.88 USD)

Commercial use of this term

Homegear 1800 Sq. Ft Infrared Electric Portable Heater with Remote Control Black (109.99 USD)

Commercial use of this term

NON CONTACT IR LASER TEMPERATURE INFRARED DIGITAL THERMOMETER SIGHT GUN. (11.75 USD)

Commercial use of this term

2015 EdenPure GEN 2 1000 Portable Remote Control Quartz Infrared Heater 5000 BTU (167.49 USD)

Commercial use of this term

LifeSmart LifePro LS-1001HH Infrared Quartz Electric Portable Heater w/ Remotes (99.99 USD)

Commercial use of this term

Nice Non-Contact LCD IR Laser Infrared Digital Temperature Thermometer Gun DBX (10.0 USD)

Commercial use of this term

LifeSmart L-HOM4-NS12 Infrared Quartz 1500W portable space heater with remote (79.99 USD)

Commercial use of this term

Non-Contact LCD IR Infrared Digital Temperature Gun Thermometer Laser Sight (12.55 USD)

Commercial use of this term

LifeSmart LifePro 8 Element Infrared Quartz Heater 1800Sqft | LS-8WQH-DLX13B (149.99 USD)

Commercial use of this term

Non-Contact Temperature Gun IR Laser Infrared Digital Thermometer Sight Handheld (12.33 USD)

Commercial use of this term

Digital Infrared Temperature Temp Gun Thermometer Non-Contact IR Laser Point New (10.54 USD)

Commercial use of this term

LifeSmart LifePro LS-1111HH Infrared Quartz Electric Portable Fireplace Heater (189.99 USD)

Commercial use of this term

Digital Non-Contact LCD IR Laser Nice Infrared Temperature Thermometer Gun MY8 (10.6 USD)

Commercial use of this term

Nubee® Temperature Gun Infrared Thermometer w/ Laser Sight FDA/FCC Approved U.S. (15.66 USD)

Commercial use of this term

Duraflame DFI-550-0 Infrared Quartz Electric Heater Stove — 5200 BTU Warmer (149.99 USD)

Commercial use of this term