结合辐射传输定律,对计算机图形学中常用的光照模型进行了一系列改进,得到了简化的可用于场景仿真的红外成像计算模型.具体改进如下:1)增加了几何体表面的温度分布和材料参数;2)在模型中引入了自发辐射项和探测器特性参数.采用光线跟踪方法构建了以该模型为基础的红外场景成像模拟仿真系统,可生成任意观察视角的3D场景红外图像.对三个典型场景进行了红外成像计算,用中波红外探测器采集到的红外图像进行对比.主观比较可看出该计算模型生成的图像与实采图像在基本特征上是相似的,验证了该模型的有效性.定量比较也说明模拟图像与实际图像在主要特征上相符,但绝对亮度上存在较大差异,分析了原因,并提出了改进方向.
By using the radiance transfer law, the illumination model which was widely used in computer graphics was remodeled into a simplified thermal infrared imaging model. The improvement of the model are as follows : 1 ) adding the surface temperature distribution and the material parameters to the geometric model, 2) introducing the self emission and the detector property into the illumination model. Based on this model, the ray tracing method was used to construct an infrared imaging system which could get the synthetic infrared images of 3D scenes from any angle of view. The infrared images were calculated for three typical 3D scenes. The calculated results were compared with the real infrared images obtained by a middle infrared band imaging camera. It shows that the infrared images obtained by thermal infrared imaging model are similar to those received by thermal infrared camera. Quantitative analysis shows that there exists difference in absolute brightness, and the reasons are analyzed.