Factors Affecting the Performance of 3D Thermal Mapping for Energy Audits in a District by Using Infrared Thermography (IRT) Mounted on Unmanned Aircraft Systems (UAS)

Infrared Thermography (IRT) is a widely used non-destructive method for energy audits. However, plenty of research indicates that the performance of passive thermography is influenced by the method of data collection. Unmanned Aircraft Systems (UAS) has been successfully employed for conducting RGB photogrammetry, but the data collected from an infrared thermal camera and an optical camera differ from one another. The infrared Thermal camera usually has a lower display resolution, is more likely influenced by ambient condition, and is limited to the distance between camera and objects. UAS is being utilized for reducing the time and complexity of data collection and for capturing detailed thermal images on large areas like university campuses or entire city districts. Meanwhile, it is important to investigate the impacts of factors such as camera angle, flight patterns, and overlap of pictures when auditing energy of a group of buildings within a district. This paper introduces the preliminary results of a study that tested factors that affect 3D thermal mapping by using a UAS. To measure the performance of mapping, this research compared the quality of rendered images generated from a mapping model constructed by drone acquired data with images acquired directly from a thermal camera. The efficiency of different UAS flying configurations were investigated. The investigation showed that the adjustment of flying configurations can improve the quality of rendered images for energy audits, even though rendered images were not as high-quality as images captured directly from a thermal camera.