Physically-based thermal simulation of large scenes for infrared imaging

Rendering large scenes in the thermal infrared spectrum requires the knowledge of the surface temperature distribution. We developed a workflow starting from raw airborne sensor data yielding to a physically-based thermal simulation, which can be used for rendering in the infrared spectrum. The workflow consists of four steps: material classification, mesh generation, material parameter assignment, and thermal simulation. This paper concerns the heat transfer simulation of large scenes. Our thermal model includes the heat transfer types radiation, convection, and conduction in three dimensions within the object and with its environment, i.e. sun and sky in particular. We show that our model can be solved by finite volume method and it shows good agreement with experimental data of the CUBI object. We demonstrate our workflow for sensor data from the City of Melville and produce reasonable results compared to infrared sensor data. For the large scene, the temperature simulation finished in appropriate time of 252 sec. for five day-night cycles.