Fast Point-Based KD-Tree Construction Method for Hybrid High Frequency Method in Electromagnetic Scattering

Owing to its advantage in fast calculation, ray-tracing technique has been widely applied in solving electromagnetic scattering of electrically large target. In order to save computational time in ray tracing, KD-tree structure is introduced to reduce the number of ray-scene intersection tests. Nevertheless, KD-tree construction usually becomes the most time-consuming step in the implementation of ray tracing. In this paper, a point-based KD-tree construction method (PKCM) is proposed to accelerate the construction of KD-tree. The basic idea is to substitute point numbers for facet numbers to accelerate the process of probing optimal splitting plane with surface area heuristic. Owing to this replacement, the searching area of PKCM is dramatically decreased compared with that of KD-tree structure with facets, thus giving rise to significant saving in computational time but without degrading performance. Simulations of the scattering of electrically large complex objects demonstrate the effectiveness of the proposed PKCM.