Close range 3D thermography: real-time reconstruction of high fidelity 3D thermograms

Book excerpt: Infrared thermography enables the non-contact measurement of an object’s surface temperature and presents the results in form of thermal images. The analysis of these images provides valuable information about an object’s thermal state. However, the fidelity of the thermal images strongly depends on the pose of the thermographic camera with respect to the surface. 3D thermography offers the possibility to overcome this and other limitations that affect conventional 2D thermography but most 3D thermographic systems developed so far generate 3D thermograms from a single perspective or from few noncontiguous points of view and do not operate in real time. As a result, the 3D thermograms they generate do not offer much advantage over conventional thermal images. However, recent technological advances have unlocked the possibility of implementing affordable handheld 3D thermal imaging systems that can be easily maneuvered around an object and that can generate high-fidelity 3D thermograms in real time. This thesis explores various aspects involved in the real-time generation of high-fidelity 3D thermograms at close range using a handheld 3D thermal imaging system, presents the results of scanning an operating industrial furnace and discusses the problems associated with the generation of 3D thermograms of large objects with complex geometries.