Monostatic Shadowing of Homogeneous Fractal Profiles. (Reannouncement with NewAvailability Information)

摘要

The effect of shadowing on the probability density of illuminated slopes isinvestigated for a class of homogeneous fractal profiles. Unlike smoother surfaces, the shadowing of slopes for a fractal surface will depend strongly on the horizontal scale over which slopes are determined. Under the approach taken, the analytic solution is difficult to solve, if not intractable. However, this approach gives rise to an approximate form to the solution that is dependent on a single parameter a. It is found that for a large range in surface morphology an alpha can always be found that yields a satisfactory fit to numerical solutions of the shadowing problem. An analytic form for alpha is proposed whose coefficients, dependent on morphological parameters and the grazing angle, are determined by an inversion of empirical fits to the numerical solution. This analytic form successfully predicts alpha to within 18% of its numerically determined value, which is likely accurate enough for most acoustic backscatter applications.