基于自适应射线管分裂的多次反射计算方法

传统弹跳射线（shooting and bouncing rays, SBR）方法采取按均匀射线管的方式进行射线追踪，因此，在计算电大尺寸复杂目标多次反射时，需要处理海量射线，计算效率极低，应用上受到很大限制。提出了一种基于复杂目标不规则三角网（triangle irregular network, TIN）模型的自适应射线管分裂算法（adaptive ray tube splitting algorithm, ARTSA），利用TIN模型信息动态生成非均匀初始射线管，经过与模型三角面元的求交、多边形裁剪和三角化处理，将初始射线管自适应分裂成多个子射线管，利用口面积分（aperture integral, AI）法计算各子射线管的多次反射场，通过相干叠加获得目标多次反射贡献。与传统SBR方法相比，在相同计算精度下，所提算法能极大地减少射线追踪数量，显著提高计算电大尺寸复杂目标多次反射的效率。

Efficient multi-reflection computational method based on adaptive ray tube splitting

The traditional shooting and bouncing rays (SBR) technique usually utilizes the small uniform ray tube for ray tracing, where a great number of rays need to be dealt with while calculating the multiple reflections for electrically large complex targets, therefore, the calculation efficiency is greatly reduced to restrict the applications. A novel adaptive ray tube splitting algorithm (ARTSA) based on the complex target’s triangle irregular network (TIN) model is presented. Firstly, the information of TIN model is used to generate non-uniform optimized initial ray tubes dynamically. After making the ray tube intersection, polygon clipping and triangularization operation, each initial ray tube is split to a certain number of sub ray tubes. Eventually, the multi-reflection contributions of complex objects are gained via the coherent superposition of all sub-ray-tube contributions calculated by aperture integral (AI). Compared with the traditional SBR technique, the proposed algorithm could reduce the number of rays greatly and enhance the efficiency of multi-reflection calculation observably with the same calculation precision.