[Multi-spectral thermometry based on radiation measurement within a finite solid-angle].

Based on Planck's law, the surface temperature of an object can be determined by measurement of emitted radiation. The equation for monochromatic radiation thermometry within a finite solid-angle was deduced, and it was found that if the surface temperature and spectral emissivity can be solved at the same time, the specific radiation measurement conditions for multi-spectral thermometry should be generally met that the radiation measurement should be implemented within an infinitesimal solid-angle or within a finite solid-angle only for a perfect diffuser. When the directional spectral emissivity modeled by finite polynomial series is employed and proper mathematical transformation is used, a universal equation for monochromatic radiation thermometry is obtained.

[Radiation thermometry based on calibration of spectral responsivity].

Abstract True surface temperatures can be determined by measurements of radiation emitted by the object. The non-spectral parameter in the radiation measurement equation is the function of the relative position between the target and the lens, so calibration of space position is necessary for temperature measurement, when emissivity and temperature are measured simultaneously. In the present paper, the non-spectral parameter was included into the undetermined coefficients of emissivity modeled by finite series, which will not affect the solution of true surface temperature.