Use of Virtual Surfaces for Prediction of Real Rough Soil Surfaces Brightness in Any Illumination and Viewing Conditions

Virtual surfaces discussed in the paper are sets of input data of the geometrical model of soil bidirectional reflectance in the optical domain which predict the reflectance behaviour of rough soil surfaces in any illumination and viewing conditions. Equal-sized opaque spheroids lying on a freely sloping plane, describe the soil surface. They are absorbed into the ground of the slope plane having their tops at a given height above the ground. The spheroids are dispersed in a net of squares of given sides. The geometrical structure is illuminated by the direct solar beams and diffuse light. The virtual surfaces are discussed on the background of their real equivalents, soil surfaces developed from dune sand and sandy loam.