Adaptive supersampling in shooting and bouncing ray method for efficient and accurate scattering prediction of electrically large objects

This paper present a new technique for determination of illuminated region in the shooting and bouncing ray (SBR) method. The ray tracing part of SBR method consumes the most of computational resources if multiple reflection effects are considered. In order to reduce the computational burden, a combination of backward ray tracing and forward ray tracing method is used for tracking the incident and reflected rays, respectively. The basic idea is to use an adaptive super-sampling technique in forward tracing process. In this technique, extra reflected rays are traced forwards through each illuminated patch to precisely determine the illuminated area by reflected rays. The number of these extra rays are adaptively obtained according to the incident angle and the geometrical properties of reflected ray, which results in significant reduction of ray intersection tests. The simulation results confirm the proper accuracy and efficiency of the presented method.