Complex Ray Interpretation of Reflection from Concave-Convex Surfaces

摘要

Reflection from a smooth target with inflection points, when investigated by the physical optics method, reveals far-zone contributions arising from real and complex stationary points. The former represent conventional specularly reflected real ray fields whereas the latter, which are nonspecular in real space, can be interpreted as complex ray fields reflected specularly from the complex extension of the scatter surface. The complex reflection points lie near real concave-to-convex transitions. These assertions are justified by physical optics and complex ray asymptotics and are confirmed by numerical comparisons. It is concluded, therefore, that a complete ray theory of reflection from the illuminated portion of a smooth object with inflection points must include specularly reflected real as well as complex rays, with the latter originating from the complex extension of the surface contour. Keywords: Transfer functions; Caustics; Reprints. (JHD)