On the temperature assignment problem and the use of confidence textures in the creation of 3D thermograms

Abstract

In infrared thermography, the temperature measured by a thermal imaging device varies with the position and orientation of the camera with respect to an object's surface. 3D thermography has hence the potential to depict the surface temperature of objects with higher fidelity than conventional 2D thermography. So far the problem of assigning temperature values that correspond to the same surface but were obtained from different perspectives has been addressed by simply overwriting previous values with new values or by averaging the measured values according to a weighted averaging scheme. A new approach to map temperature values onto a 3D model is proposed that results in a more faithful representation of an object's real surface temperature in form of a 3D thermogram. Temperature values are assigned in real time to the 3D model taking into consideration the observation conditions under which they were measured. These conditions are also made available to the user in form of textured 3D models, where the texture color depicts the level of confidence associated to the thermal measurements. These textures provide useful additional information about the 3D thermogram. The new approach is especially helpful in the real-time generation of 3D thermograms as the user gets live feedback on the quality of the thermal model being generated.