What is the principle of Near Infrared Spectroscopy?

What is the principle of Near Infrared Spectroscopy?

Near infrared (NIR) spectroscopy is based on the absorption of electromagnetic (EM) radiation at wavelengths in the range 780 to 2,500 nm. The light interacts with the sample and the detector measures its transmittance and absorbance.

What is near infrared used for?

Near Infrared Spectroscopy and Imaging (NIRS) uses near infrared light between 650 and 950 nm to non-invasively probe the concentration and oxygenation of hemoglobin in the brain, muscle and other tissues and is used e.g. to detect changes induced by brain activity, injury, or disease.

What is the difference between NIR and IR?

IR (4000400 cm 1) spectroscopy elucidates chemical information from the fundamental vibrational transitions. In contrast, the signal that was measured in NIR (10,0004000 cm 1) spectroscopy originates from the excitations of higher quanta transitions, mostly first overtones and binary combinations [16,17,18].

What does NIR measure?

The NIR instrument measures the proportion of light which is reflected by the material which is analyzed. Just as we have trained ourselves to recognize weak and strong teas just by looking at their color intensity, we need to train the NIR instrument to be able to see the difference between different concentrations.

How does NIRS monitoring work?

Near-infrared spectroscopy (NIRS) is a noninvasive technique that can continuously monitor regional oxygen saturation (rSO2), which reflects the perfusion status and oxygenation status of underlying tissues at the bedside [7]. … It reflects the balance between tissue oxygen supply and demand.

What is infrared reflectance?

Reflectance infrared spectroscopy has been primarily used as a characterization tool to study the molecular orientation, average conformation order, and chemical identity of thin films (<10 nm) on metallic surfaces.

Is near infrared light visible?

Far-Infrared Light. The farther away a wavelength gets from visible light, the longer the wavelength becomes and the closer it gets to the microwave range. You can’t see or feel near-infrared light.

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What does near infrared show remote sensing?

Remote sensing makes use of visible, near infrared and short-wave infrared sensors to form images of the earth’s surface by detecting the solar radiation reflected from targets on the ground. … Thus, the targets can be differentiated by their spectral reflectance signatures in the remotely sensed images.

Why is it called near-infrared?

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.

When was near-infrared spectroscopy invented?

1881 The first (near) infrared spectra were measured in 1881 by Abney and Festing using photographic plates. Not only did they produce the first spectra but they also suggested, correctly, that the absorptions were related to the chemical composition of the liquids they investigated.

What are Far-Infrared Rays?

Far-Infrared Rays are waves of energy, totally invisible to the naked eye, which penetrate the surface of the skin where they gently and elevate the body’s surface temperature to 107.6F/42C and above, whilst positively activating body systems and functions.

What does near infrared spectroscopy NIRS measure?

Near-infrared spectroscopy (NIRS) is a brain imaging method that measures light absorbance to calculate oxy-hemoglobin (oxy-HB) and deoxy-hemoglobin (deoxy-HB), which provides an indirect measure of brain activity, particularly in the frontal cortex.

What are normal NIRS?

Normal values for NIRS values are between 6075% but physiological values of 5560% have been reported in some cardiac patients [7]. Therefore, trends in values are considered more important in clinical practice than the absolute values [8].

What is NIRS NICU?

Continuous brain monitoring tools are being used more frequently in the neonatal intensive care unit (NICU) to assess brain health. Near infrared spectroscopy (NIRS) is a non-invasive tool to continuously measure regional tissue oxygenation at the bedside.

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How does reflectance spectroscopy work?

Reflectance spectroscopy is an emerging technology among the new optically based endoscopic techniques. … Unlike autofluorescence spectroscopy, the reflected light maintains the same wavelength, although different wavelengths are absorbed and reflected to different degrees.

How is reflectance defined?

Reflectance is defined as the proportion of perpendicularly incident light reflected from a component compared to that reflected from a standard of known reflectance.

Is near infrared hot?

Near infrared light is closest in wavelength to visible light and far infrared is closer to the microwave region of the electromagnetic spectrum. … Shorter, near infrared waves are not hot at all – in fact you cannot even feel them.

Is near infrared harmful?

There are, in fact, known risks to near-infrared radiation exposure. … More worryingly, IR-A radiation can penetrate deeply into the skin and cause tissue damage, resulting in photoaging of the skin (Schroeder et al. 2008, Robert et al. 2015), and at worst, possibly skin cancers (e.g., Schroeder et al.

How much of sunlight is near infrared?

The spectrum of solar radiation reaching the Earth ranges from 290 to more than 1,000,000 nm and is divided as follows: 6.8% UV, 38.9% visible, and 54.3% near infrared radiation (NIR) [1].

Why is near infra red relevant when studying vegetation?

Reflected near-infrared radiation can be sensed by satellites, allowing scientists to study vegetation from space. … Thus, analyzing a plants spectrum of both absorption and reflection in visible and in infrared wavelengths can provide information about the plants’ health and productivity.

Can Near Infrared see through clouds?

Finally, near infrared light can penetrate haze, so including this band can help discern the details in a smoky or hazy scene. … Shortwave-infrared bands are also useful for distinguishing between cloud types (water clouds versus ice clouds) and between clouds, snow, and ice, all of which appear white in visible light.

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How spectroscopy is used in remote sensing?

[1] Imaging spectroscopy is a tool that can be used to spectrally identify and spatially map materials based on their specific chemical bonds. Spectroscopic analysis requires significantly more sophistication than has been employed in conventional broadband remote sensing analysis.

What is the range of IR spectroscopy?

The infrared range covers 700-1000 nm (wavelength), or 14,286-12,800 cm 1 (wavenumber), and ultraviolet radiation has wavenumbers above these, approximately, 25,000 50,000 cm 1, or 100 to 400 nm (wavelength).

What is far IR region?

Far infrared (FIR) is a region in the infrared spectrum of electromagnetic radiation. Far infrared is often defined as any radiation with a wavelength of 15 micrometers (m) to 1 mm (corresponding to a range of about 20 THz to 300 GHz), which places far infrared radiation within the CIE IR-B and IR-C bands.

What is the history of IR spectroscopy?

Infrared spectrophotometers were developed in the US in the mid 1940s. Initially, their applications were confined to R&D work on organic compounds, mainly in the petrochemical field. The first Japanese instruments were manufactured in 1954 by the Applied Optics Research Institute, the predecessor of JASCO.