TY - JOUR

T1 - Multi-wavelength pyrometry based on robust statistics and cross-validation of emissivity model

AU - Taunay, Pierre Yves C.R.

AU - Choueiri, Edgar Y.

N1 - Funding Information:
This work was supported by the Program in Plasma Science and Technology at Princeton University. The authors would like to thank Sebastián Rojas Mata and Christopher Wordingham for their constructive comments.
Publisher Copyright:
© 2020 Author(s).

PY - 2020/11/1

Y1 - 2020/11/1

N2 - A systematic and automated procedure to calculate the temperature of a surface with unknown emissivity from radiance measurements performed at a large number of wavelengths is presented, and statistical methods are applied to quantify its accuracy and precision. Unlike existing multi-wavelength pyrometric approaches, the proposed cross-validated procedure tests multiple emissivity candidates on multiple, randomly chosen subsets of the radiance measurements. The procedure uses solely an emissivity model to provide an accurate temperature value and retrieves the true emissivity from the ratio of the measured radiance to that of a blackbody calculated from the determined temperature. For a given emissivity model, the temperature is computed using the average of all possible combinations of two-wavelength ratios. The emissivity model that minimizes the coefficient of dispersion is selected. Accuracy and precision are quantified for the case of known emissivity. It is shown that, at least in the case where wavelengths are linearly distributed, the method is accurate, the precision increases with the total number of wavelengths, and it is maximized if the ratio of the minimum to maximum wavelength is equal to 2.46. The procedure is applied to both numerical and experimental data from the literature. Excellent agreement of the calculated temperature and emissivity is obtained for both datasets.

AB - A systematic and automated procedure to calculate the temperature of a surface with unknown emissivity from radiance measurements performed at a large number of wavelengths is presented, and statistical methods are applied to quantify its accuracy and precision. Unlike existing multi-wavelength pyrometric approaches, the proposed cross-validated procedure tests multiple emissivity candidates on multiple, randomly chosen subsets of the radiance measurements. The procedure uses solely an emissivity model to provide an accurate temperature value and retrieves the true emissivity from the ratio of the measured radiance to that of a blackbody calculated from the determined temperature. For a given emissivity model, the temperature is computed using the average of all possible combinations of two-wavelength ratios. The emissivity model that minimizes the coefficient of dispersion is selected. Accuracy and precision are quantified for the case of known emissivity. It is shown that, at least in the case where wavelengths are linearly distributed, the method is accurate, the precision increases with the total number of wavelengths, and it is maximized if the ratio of the minimum to maximum wavelength is equal to 2.46. The procedure is applied to both numerical and experimental data from the literature. Excellent agreement of the calculated temperature and emissivity is obtained for both datasets.

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U2 - 10.1063/5.0019847

DO - 10.1063/5.0019847

M3 - Article

C2 - 33261433

AN - SCOPUS:85095863997

SN - 0034-6748

VL - 91

JO - Review of Scientific Instruments

JF - Review of Scientific Instruments

IS - 11

M1 - 114902

ER -