Influence of the Object's Emissivity on the Accuracy of Infrared Temperature Measurement

Abstract

This paper aims to explain importance of emissivity in non-contact measurement. The significance and methods of contactless temperature measurement, as well as the physics of non-contact measurement, are presented. Non-contact temperature measurement method is based on the laws of radiation. The temperature value that will be measured by this method depends on the temperature and the emissivity of the object. To understand the importance of emissivity for accurate temperature measurement, first of all the term of emissivity is explained more closely. Furthermore, the parts of the laboratory equipment, which was used to experimentally determine the influence of the object’s emissivity on the accuracy of temperature measurement, are explained. The body with known emissivity was heated and its temperature was measured using an infrared sensor. In order to predict impact of emissivity of body on accuracy of temperature measurement emissivity was varied from 0.7 to 1.0 by the software. Six body’s temperature points were used for analysis. The measured temperature values are shown, as well as the deviations of the measured temperature from the actual body temperature. The graphical representation is given for a better understanding of the measurement error caused by used wrong value of body emissivity.