Non-Contact Method of Measuring Surface Temperature

Abstract

A non-contact method is proposed for measuring the surface temperature of an object using a standard radiator and standard object having optico-physical properties identical to those of the monitored object. Placed co-planarly with the monitored object in the field of view of an optoelectronic system (OES) is a standard object, the temperature of which is regulated and measured, and a standard radiator, whose normal spectral emissivity and temperature are known. In addition, the OES has its three fixed points, at which it registers the normal emissivity of the standard object, monitored object, and standard radiator (SR). The main distinction of the proposed method from the known ones is that the limits or tolerances for the nature of reflection and the quantitative parameters of reflection of the monitored object make no difference. The obtained analytical expression is an equation of the non-contact method of measuring the surface temperature of the monitored object, which can be applied for any spectral range of operation of the OES. A metrological analysis of the proposed method is made using a monochromatic optoelectronic system working at wavelengths of 0.65, 2.0, 5.0, 14.0, and 50.0 μm for the temperature of the monitored object, T, equals to 400, 700, and 1000 K. Based on the analysis of the results the requirement for the implementation of the proposed method of measuring the surface temperature has been formulated, which says that the choice of an optoelectronic system for measuring the surface temperature of objects should be preceded by a methodological and metrological analysis of the optico-physical properties of the monitored object, the surrounding background, and the OES itself.