New Technique for Emissivity Free Temperature Measurement Applying Multivariate Analysis to Spectral Radiation

Abstract

Steel making plants have a variety of heating processes. Emissivity compensation is still one of the most difficult problems when radiation thermometers are applied to heated sheet in steel making processes. In previous reports 1), 2) , the authors proposed a new technique using spectral information of radiation from targets and multivariate analysis, such as principal analysis (PCA) or partial least squares (PLS). This paper describes the basic concept of the technique and shows the effectiveness by simulations using calculated and measured reflectance data of various thickness films on steel sheet.

Emissivity-free radiation thermometry based on multivariate analysis of spectral radiance applied to steel-making process

“…The basic concept has been presented in previous articles [13,14]. Considering the convenience of the readers, all the contents necessary for understanding this paper are reproduced here with added accuracy and detail.…”

“…Figure 1. Schematic of concept of thermometry technique using principal components [14]. Reproduced with permission from [14] ©The Society of Instrument and Control Engineers (2016).…”

“…In order to overcome the basic problem of unknown emissivity, the authors proposed a new technique [13,14] for emissivity-free temperature measurement that does not belong to any of the five types described above. In the proposed technique, spectral radiation from the object to be measured is detected, and temperature-dependent spectral radiance is distinguished from emissivity-dependent spectral radiance by the difference of their spectral characteristics.…”

“…Figure 12.Calibration function[14]. Reproduced with permission from[14] ©The Society of Instrument and Control Engineers (2016).…”

“…Figure 15.Comparison of simulated measurement errors induced by emissivity deviation between conventional single-wavelength and proposed thermometer[14]. Reproduced with permission from[14] ©The Society of Instrument and Control Engineers (2016).…”