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The MODIS (Moderate Resolution Imaging Spectrometer) UCSB Emissivity Library is a collection of Emissivity measurements of natural and man made materials that may be used as a source of spectral emissivities at the component level in the TIR BRDF models to calculate the scene emissivities in the split-window channels to be used in the LST algorithms.
This data set was collected by Dr. Zhengming Wan’s Group at ICESS (Institute for Computational Earth System Science) located on the campus of UCSB (University of California, Santa Barbara).
By DAVID J. WATMOUGH & R. OLIVER, Department of Radiation Physics, Churchill Hospital, Oxford.
Citation: Nature 219, 622 – 624 (10 August 1968); doi:10.1038
The emissivity of human skin epsilon(lambda) in the range 2micro to 6micro has recently assumed considerable importance because of the increasing medical use of infrared scanners to measure skin temperature (t). Several commercially available scanners utilize indium antimonide detectors which are sensitive in the range 2micro to 5.4micro . Such machines measure the energy (Q) Bactrim radiated by the skin and, being calibrated against a standard black body, changes in Q are represented as variations in skin temperature. Dreyfus1 has shown that Q is related to t by an equation of the form, where k is a constant, and where the index n depends on lambda as lambdamax being the wavelength corresponding to the maximum in the emission curve. The importance of variations in emissivity can be seen by differentiating equation (1) for constant Q. We obtain which simplifies to give for Deltat For a skin temperature of 27° C (t=300° K), n is about 12.5. It follows from equation (2) that if epsilon(lambda) were to vary by as much as 5 per cent over the skin surface, this would be interpreted by the scanner as a temperature variation of about 1° C. A fairly accurate knowledge of epsilon(lambda) is thus necessary, for hot spots with temperature elevations of only 2° C are considered to be of clinical significance.
A 2004 Amercian Geophysical Union Conference Presentation by:
Schmugge, T (firstname.lastname@example.org) , USDA/ARS Hydrology and Remote Sensing Lab, Bldg. 007 – BARC West, Beltsville, MD 20705 United States
Ogawa, K (email@example.com) , Hitachi Ltd., 4-6 Kanda-Surugadai Chiyoda- Ku,, Tokyo, 101-8010 Japan
Ogawa, K (firstname.lastname@example.org) , Faculty of Engineering,University of Tokyo, University of Tokyo, Tokyo, 113-0033 Japan
Rokugawa, S (email@example.com) , Faculty of Engineering,University of Tokyo, University of Tokyo, Tokyo, 113-0033 Japan Read More »
Emissivity makes a temperature difference for infrared thermometers.
In the YouTube video below, Frank Liebman, an engineer with Fluke Corporation’s Hart Scientific Division demonstrates the impact that surface emissivity has on temperature measurement and temperature calibration using a modified Fluke blackbody calibrator and Fluke Thermal Imager.
We were surprised to see that no one commented on this video, despite an ending that leaves one hanging, at least us, with the obvious question: How do you do a radiometric calibration of a surface of unknown emissivity using a Fluke Blackbody Calibrator?
Do you have any ideas?