The infrared imaging equipment is widely used because it can acquire more thermal and material information from
infrared band than from visible band. Based on the lighting model which is widely used in computer graphics and the
radiation transfer law, a simplified thermal infrared imaging computation model is derived. The following works have
been done to derive the model: 1) Adding the surface temperature distribution of the 3D model; 2) Specifying the
physical material of the 3D geometry model; 3) Merging the self emitting and the detector response into the imaging
model as one term. The ray tracing method is applied to construct an infrared imaging simulation system which can
generate the synthetic infrared images of a 3D scene from any angle of view.
To validate the infrared imaging computation model, several typical 3D scenes are made, and their infrared images are
calculated to compare and contrast with the measured infrared images obtained by a middle infrared band imaging
camera. The result shows that: 1) The infrared imaging computation model is capable of producing infrared images
which is very similar to those received by thermal infrared camera; 2) The infrared imaging computation model can well
simulate the relative brightness contrast in the infrared images, it also can reflect most of the basic infrared imaging
characteristics; 3) Some geometry, thermal and material information also can be retrieved from the synthetic infrared
images. Quantitative analysis shows that the absolute brightness does not match well, and the reasons are analyzed. By
the synthetic infrared images, it also illustrates the difficulty and complexity in infrared image analysis and simulation.