A hybrid model based on the geometrical optics and physical optics (GO-PO) method and facet-based asymptotical model (FBAM) for the composite EM scattering from sea surface with ship has been previously developed. But, the GO-PO method faces a difficult problem that the lower efficiency in testing the visibility of patches to the incident and reflected waves. Hence, to improve the computation efficiency of the GO-PO method, a kd-tree accelerated hybrid model is presented in this paper. The kd-tree method firstly carries out the intersection test between the ray and the bounding box where the patch is located before the operation between the ray and the patch. If the distance parameters of the bounding box do not meet the requirement, the ray is not necessary to enter the bounding box, which can reduce the needless intersection tests. Numerical results show that the proposed kd-tree accelerated hybrid model could improve the efficiency about three times and could be applied to the study of composite EM scattering characteristics of electrically large sea surface with a ship target.

中文翻译：

---

基于Kd-Tree加速混合模型的舰船复合电磁散射研究

先前已经开发了基于几何光学和物理光学（GO-PO）方法以及基于面的渐近模型（FBAM）的混合模型，用于从船上从海面散射复合电磁。但是，GO-PO方法面临一个难题，即测试斑块对入射波和反射波的可见性的效率较低。因此，为提高GO-PO方法的计算效率，提出了一种kd树加速混合模型。kd-tree方法首先在射线与补片之间进行操作之前，进行射线与补片所在的边界框之间的相交测试。如果边界框的距离参数不符合要求，则不需要射线进入边界框，这样可以减少不必要的相交测试。