  We present a semi-analytical model to simulate bidirectional reflectance
distribution function (BRDF) spectra of a rough slab layer containing
impurities. This model has been optimized for fast computation in order to
analyze hyperspectral data. We designed it for planetary surfaces ices studies
but it could be used for other purposes. It estimates the bidirectional
reflectance of a rough slab of material containing inclusions, overlaying an
optically thick media (semi-infinite media or stratified media, for instance
granular material). The inclusions are supposed to be close to spherical, and
of any type of other material than the ice matrix. It can be any type of other
ice, mineral or even bubbles, defined by their optical constants. We suppose a
low roughness and we consider the geometrical optics conditions. This model is
thus applicable for inclusions larger than the considered wavelength. The
scattering on the inclusions is assumed to be isotropic. This model has a fast
computation implementation and thus is suitable for high resolution
hyperspectral data analysis.
