Use of the “grey body emissivity” algorithm for processing hyperspectral remotely sensed data

Multispectral imaging systems operating in the thermal infrared spectral range (TIR) provide a measurement set of spectrally integrated radiance in various finite-bandwidth spectral channels. The observed spectral radiance is related to the temperature of the target and to its spectral emissivity by an integral equation that is presented in this article. All the atmospheric effects are disregarded. This equation involves channel sensitivity, bandwidth and radiation constants. Direct retrieval of temperature and emissivity does not imply just one solution, having the system N equations and N+1 unknowns. The system uncertainty may be removed only by applying a certain a priori assumption, which defines a model for temperature and emissivity retrieval. The model assumption may not always be verified and should be considered an approximation. Up to now, several of these models have been developed. The authors discuss the mathematical structure of their model called “grey body emissivity”