Abstract
We propose a new method for radiation thermometry to determine the true temperature without a priori knowledge about the value of emissivity. This method uses a nonlinear emissivity modification attributed to the multiple-reflection induced by a half mirror put closely and parallel to the object in the optical path of radiation. Direct and indirect (through the half mirror) measurements of the radiation from the object give us the value of the true temperature and the emissivity of the object simultaneously. The validity of this method was confirmed empirically for various samples at the temperature from 300°C to 400°C. The samples had the emissivity from 0.1 to 0.9 and surfaces of different scattering properties. The estimation error was less than 10°C except for a sample with very low emissivity and highly scattering surface.
