地表热辐射时序变化模拟是红外场景仿真的核心环节。利用地表热传导差分计算地表热辐射是物理上较严谨的模拟方法, 但受限于差分方程边界条件的不确定性, 在红外场景仿真中未得到广泛应用。提出一种基于光照、气温、湿度等环境参数的地表热辐射时序变化计算方法。重点根据地质热环境变化规律设计闭环迭代过程, 自动修正初始和下边界热辐射值, 解决了边界条件的不确定问题, 提高了地表热传导计算精度和算法适应性。野外实验结果表明: 该算法计算温度与实测温度绝对误差小于2 K, 等效黑体辐射度相对误差小于3%, 为准确模拟红外动态场景提供基础。此外, 利用该方法对山区地表的热辐射分布时序变化进行了模拟, 显示了其在红外场景仿真方面的初步应用效果。

Estimation of time series dynamic thermal radiation of terrain surface is the core section in IR scene simulation. Calculating land surface thermal radiance by heat-transfer Finite Difference Method(FDM) is a physically rigorous method. However, it is limited to the uncertainty of boundary conditions of the difference equation, therefore the method is not widely used in IR scene simulation. A simulation method of time series dynamic thermal radiation of terrain surface based on environmental parameters(illumination, temperature, humidity, etc) was proposed. In this method a closed-loop iterative process was designed according to the variable regulation of geological thermal environment. It could automatically correct the initial temperature profile and bottom boundary thermal radiance, which solved the problem of uncertainty of boundary conditions, and the algorithm accuracy and adaptability were promoted. The outfield experimental results indicate that the absolute error of temperature is less than 2 K, and the relative error of equivalent blackbody radiance is less than 3%. Compared with previous methods, the precision of this method has been improved obviously. The method provides the fundamental module for IR scene simulation. In addition, this method was used to simulate the temporal changes of the thermal radiation distribution on the surface in mountain area, showing its preliminary application effect in infrared scene simulation.