3D tools for building and infrastructures inspection from thermal UAS data: first steps

Thermal imaging has been widely used for the inspection of human-made and natural scenarios, from electrical installations and advanced machinery to buildings. Regarding buildings, it can be used to assess problems concerning heat, airflows, and water. Hence, thermography has been increasingly applied to the energy efficiency of new and old buildings. Some examples of applications are the detection of heating and cooling losses, moisture sources, missing insulation, floor heating failures, and the evaluation of building restorations. However, the main drawback of thermal imagery is its reduced resolution, e.g., 640 × 512, which is significantly lower than RGB imagery. In the case of buildings, cameras or thermal sensors mounted on UAS (Unmanned Aerial System) offer a wider range of possibilities by acquiring areas not accessible by other surveying methods. This paper presents a tool that allows building dense 3D thermal point clouds applied to conserving buildings and infrastructures inspection. Also, the aim of this work is to provide a visualization solution of the generated point clouds, thus allowing a human operator to analyze building defects. Accordingly, the rendering is improved by taking advantage of modern Graphical Processing Unit (GPU) capabilities, while also considering the occlusion for the accurate assignment of thermal information to the point cloud. Due to the high response time of the procedure, the complete pipeline is accelerated using GPU programming. Finally, our method is proven to generate point clouds with a higher number of points and density than notable commercial solutions, while also lowering the response time.