The invention provides a method for calculating spectral
emissivity and true temperature. A multi-spectral thermodetector is adopted for measuring the spectral
emissivity and the true temperature of a luminous body to be measured. The method comprises the steps that 1, an optical splitter is adopted for dividing light emitted by the luminous body to be measured into multiple ways of light with different wavelengths; 2, multiple channels of the multi-spectral thermodetector receive the light of the corresponding ways, so that the
brightness temperature of the light of each way is obtained; 3, the relation expression between the
brightness temperature measured by each channel and the true temperature is obtained on the basis of the preset rule, please see the relation expression in the description, Ti represents the
brightness temperature of the i channel, T represents the true temperature, Lambada i represents the wavelengths of split beams received by the i channel, C2 represents a second
radiation constant, and Epsilon(Lambada i, T) represents the spectral
emissivity of the i channel; 4, the iteration
cut-off condition is obtained on the basis of the temperature relation expression and the preset conversion rule, and please see the iteration
cut-off condition in the description; 5, based on a
gradient projection method and the spectral emissivity value
ranging from 0 to 1, the spectral emissivity and the true temperature are calculated.