The major error of temperature measurements of different objects is due to uncertainty of their emissivity factor value. And vice versa, for correct determination of a true temperature, using conventional temperature means (pyrometers, thermal image cameras), one has to know in advance the emissivity factor of the studied object’s surface or better to set its value in place immediately before a measurement. The latter is proposed by authors to significantly increase the accuracy of temperature measurement. Namely, it needs to change previously the temperature of the sensitive element of a measuring mean and carry out measurements. The similar procedure is performed under the unchanged temperature condition. The difference between temperature readings of the same point of the studied surface gives the possibility to compute an emissivity factor. It improves the measurement accuracy. Derived equations allow fulfilling the specified operation at different temperature differences of the sensitive element.
 S. Yatsyshyn, B. Stadnyk, Ya. Lutsyk, L. Bunyak, Handbook of Thermometry and Nanothermometry, IFSA Publishing, Barcelona, Spane, 2015.
 B. Stadnyk, P. Skoropad, Features of determining the factor of radiation ability of materials at low temperatures. Measuring Equipment and Metrology, no. 68, p. 165–168, 2008.
 Mikron Instrument Company, Inc., Table of Emissivity of Various Surfaces for Infrared Thermometry, 10 p. http://www-eng.lbl.gov/~dw/projects/DW4229_ LHC_detector_analysis/ calculations/emissivity2.pdf
 S. Yatsyshyn et al. Method for determining the emissivity factor of materials. Pat.116684 UA, 25.04.2018, bul.8, 2018 (in Ukrainian).