A PHOTOMETRIC FUNCTION FOR DIFFUSE REFLECTION BY PARTICULATE MATERIALS

摘要

A photometric function is proposed to describe the diffuse reflection of radiation by particulate materials. Both multiple scattering and the dominant effects of particle shadowing are included and the function is verified by comparisons with the photometries of laboratory surfaces. The function is a major improvement over the frequently used, strictly empirical, and much simpler Minnaert function in that brightness measurements of planetary and other diffusely scattering surfaces can be used to calculate the brightness for geometries other than those used in the measurements and for which the Minnaert function does not apply;the measurements also can be directly related to such surface characteristics as particle size, single-particle albedo, and compactness.