Estimating index of refraction, surface temperature, and downwelling radiance using polarimetric-hyperspectral imagery (P-HSI)

A method for retrieving index of refraction from polarimetric hyperspectral imagery (P-HSI) has been developed using a model to describe the spectral variation of the index. Index of refraction is modeled in one of two ways to reduce the number of parameters in the problem. Additionally, MODTRAN is used to model the atmosphere, further reducing the number of variables and enabling an overdetermined solution to be found. Results from simulated data of a SiC target at 25°C, with realistic noise levels, show index is retrieved to within 0.0116 for the real component and 0.034 for the imaginary component. This also shows that the atmospheric downwelling can be accurately retrieved even without a priori knowledge.