随机粗糙面散射中遮蔽效应算法的改进

Improvement of shadowing effect algorithm in random rough surface scattering

运用线性滤波法生成了高斯型二维随机粗糙面,采用基尔霍夫近似法分析了随机粗糙面的散射,针对传统几何遮蔽方法研究散射中遮蔽效应计算量大的问题,对几何遮蔽算法进行了改进,提出利用粗糙面与通过临界面元的入射光线位置关系来计算入射遮蔽,借助散射光、粗糙面在xoy面投影是否有交点来计算散射遮蔽,计算效率得到显著提高.数值计算了S波和P波入射到铁表面时入射面内散射光强的分布,结果与文献成果符合较好,证明了改进算法的有效性.进一步模拟了半球空间的散射光强分布,结果表明散射光强主要集中在与入射光镜像方向附近,散射角方向半宽度约40°,散射方位角方向半宽度约60°,P波入射时的散射光强小于S波入射时的散射光强,能够为目标探测提供理论参考.

Gauss random rough surface is generated by linear filtering method,and Kirchhoff approximation is used to analyze the scattering of random rough surface.An improved geometric shadowing algorithm is proposed to large amount of calculation for traditional ray-tracing method.The calculation efficiency is significantly improved by using the position relation between rough surface and the incident light passing through the critical micro-facet to calculate incident shadowing,and whether the intersection point of scattered light projection and rough surface projection on the xoy plane to calculate scattering shadowing.The scattered light intensity distribution in the incident plane when S-polarization and P-polarization light incident on the iron surface is numerically calculated,which agrees well with the literature results and proves the effectiveness of the improved algorithm.The scattered light intensity distribution in hemispherical space is simulated.The results show that the scattered light intensity is mainly concentrated near the mirror direction with the incident light,the half-width in the scattering angle direction is about 40°,and in the scattering azimuth direction is about 60°,the scattered light intensity of P-polarization wave is less than the scattered light intensity of S-polarization wave.These results can provide theoretical reference for target detection.