Reduction of the impact of emissivity on high temperature measurements in non-contact thermometric devices

Non-contact measurements of high temperature, accomplished with the use of infrared cameras and pyrometers, are utilized in many fields of science and industry. However, in order to obtain reliable measurement results from aforementioned devices, one should take account of the emissivity value of a thermal source the temperature of which is being measured. This is due to the necessity of calibration of non-contact thermometric devices in relation to emission characteristics of a blackbody, which is an ideal source with the maximum emissivity value. In order a non-contact temperature measurement was made possible without the necessity of taking into account the emissivity value, an original concept of the measurement method was developed, taking the advantage of thermal radiation laws – Planck’s law and Wien displacement law. The basic idea of the accepted method is the departure from amplitude recording (as in “conventional” pyrometry and thermovision) for linking of temperature recording with a maximum position in Planck’s curve. This article presents a novel approach that was used in the development of an original algorithm of temperature determination for performance of non-contact measurements of high temperature. The algorithm will enable to perform measurements without the necessity of introducing the emissivity value of a radiation source into a measurement instrument and will limit the impact of radiation absorption via the medium in which a measurement is being performed on the results of measurements. The applied methodology will allow conducting non-contact temperature measurements at a distance without the necessity of calibration the measuring device with regard to a blackbody