Approach on directional thermal emission modeling for 3-D structural pixel and the model validation

For a remote sensing pixel with 3D surface, the directionality of thermal emission depends on the component parameters of the pixel, such as component temperatures, component emissivities and structural parameters of the pixel. The contribution of the multiple scattering between components to the directional thermal emission is mainly effected by the pixel 3D structure. We present a model to describe the multiple scattering between components and its contribution to the pixel's emission quantitatively, based on the geometric-optical thermal emission model (Li et al. 1999) and the principle of multiple bouncing (Su et al. 2000). For the non-isothermal pixel with random distributed components, the directional thermal emission model is developed. A set of measurement data including directional thermal emission and component parameters are used in the model validation. The result demonstrates that in pixel scale the analytical model prediction fits the measurement well.