Numerical correction of infrared two-color thermometry

Being supposed that the target is greybody in the principle of two-color pyrometry, the color temperature is regarded as the true temperature. The main cause of the error is emissivity. In published literatures on emissivity ε, the wavelength λ was taken into account but the temperature T was neglected. The curve of ε(λ) against λ could be obtained in certain temperature. In this paper the emissivity is considered that it relates not only with wavelength but also with temperature, and the expression of ε(λ,T) can be gained. Therefore, a series of ε(λ) against λ curves under different temperature can be united into the form of ε(λ,T).