Emissivity measurement and temperature correction accuracy considerations

Authors: Madding, Robert P.
Affiliation: AA(Inframetrics, Inc.)
Publication:
Proc. SPIE Vol. 3700, p. 393-401, Thermosense XXI, Dennis H. LeMieux; John R. Snell; Eds. (SPIE Homepage)
Publication Date:03/1999
Origin:SPIEAbstract Copyright:
(c) 1999 SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Bibliographic Code: 1999SPIE.3700..393M
Abstract: Extraction of temperatures or temperature differences with thermography is not possible without knowledge of the target emissivity...

Emissivity Adaptation

A project under the Tufts University Research for Undergraduates 2000 Program described both theory and experiments related to welding of metals. Its report is online (CLICK HERE FOR FULL REPORT) and the Abstract is below.

Abstract

"The basic assumption behind the operating principle of modern thermal imaging thermometers is a “graybody approximation”. For a graybody, the emittance, reflectance and transmittance are constant for all wavelengths within the wavelengths within the waveband over which the instrument measures.

"In reality however, these factors change, and for applications that take place over a wide temperature range, the emissivity variation needs to be taken into account. This work suggests a method for an in-process emissivity identification and adaptation in order to dynamically calibrate infrared temperature measurement systems for applications like heat treatment, welding, cutting etc. A series of experiments has proven that once the spatial and temporal components of emissivity are decoupled, a model can be developed, which in conjunction with direct IR radiosity monitoring can provide information about the required emissivity compensation."

Polarized spectral emittance from periodic micromachined surfaces. II. Doped silicon: Angular variation

PJ Hesketh, JN Zemel, B Gebhart - Physical Review B, 1988 - APS Polarized spectral emittance from periodic micromachined surfaces. II. VOLUME 37, NUMBER 18

From the Abstract:The polarized directional spectral (3 um <=lambda =>14um) emittances (PDSE’s) of highly doped, micromachined, periodic structures on silicon were measured...

Polarized spectral emittance from periodic micromachined surfaces. I. Doped silicon: The normal direction

Peter J. Hesketh, Jay N. Zemel & Benjamin Gebhart ; Physical Review B.37.10795
VOLUME 37, NUMBER 18 1988

From the Abstract: The normal, polarized spectral (3 um <=lambda =>14um) emittances of highly doped, micromachined, periodic structures on heavily phosphorus-doped (110) silicon ([P]?5×10¹⁹cm^-3) were measured for .....

High-Temperature Spectral Emittance of Oxides of Erbium, Samarium, Neodymium and Ytterbium

Author: Guazzoni, Guido E.¹

Source: Applied Spectroscopy, Volume 26, Issue 1, Pages 1-113 (January/February 1972) , pp. 60-65(6)

Publisher: Society for Applied Spectroscopy

Abstract: Normal spectral emittance data are reported for solid specimens of the oxides of erbium, samarium, neodymium, and ytterbium... over the spectral range ..0.5-5.0 um and at sample temperatures from 1540 up to 1870 K.

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