ON ACCURACY OF CONTACTLESS TEMPERATURE MEASUREMENT LIMITED BY UNKNOWN EMISSIVITY FACTOR

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.