title: [Multi-spectral thermometry based on radiation measurement within a finite solid-angle].
abstract: 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. So the restrictions in radiation measurement can be got rid of, but spectral emissivity may not be solved simultaneously. Multi-solution problem was preliminarily investigated, and so a solution was put forward that the channel number should be more than the number of the variables to be solved and the nonlinear least squares method should be used.
authors.affiliation: Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei 230027, China. xchyun@mail.ustc.edu.cn
authors.forename: Cheng-Yun
authors.initials: CY
authors.lastname: Xin
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Cheng
authors.forename: Zhong-Zheng
authors.initials: ZZ
authors.lastname: Zhang