Infrared Uncertainty Budget Determination in an Industrial Application

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Infrared Uncertainty Budget Determination in an Industrial Application (146.56 KB)

In infrared (IR) temperature measurement there is quite a bit of concern about how uncertainties affect the accuracy of temperature measurements. This is especially the case when nonblackbodies are being measured. Among the larger uncertainties that can effect an infrared temperature measurement are emissivity, spectral response, blackbody or gray body temperature uncertainty, optical scatter, size of source effect, and transfer standard uncertainty. Emissivity coupled with spectral response when measuring a non-blackbody can be especially troublesome since emissivity can vary with wavelength. Other factors that are minor contributors to uncertainty are alignment, calibration geometry, atmospheric losses and background temperature. Even though these factors are generally not as large, they should be considered as well. For an adequate radiometric uncertainty budget, all of these uncertainties must be evaluated.

This paper discussions the calculation of uncertainty budgets for infrared thermometry in an industrial application. It discusses the measurement equation used for uncertainty budget calculation and covers the merits of using this equation as opposed to other equations. It goes into the major uncertainties in these infrared uncertainty budgets and speaks to how they are applied to the measurement equation.