| 3D THERMAL MAPPING OF BUILDING ROOFS BASED ON FUSION OF THERMAL AND VISIBLE POINT CLOUDS IN UAV IMAGERY |
| Paper ID : 1227-SMPR |
| Authors: |
|
Mitra Dahaghin *, Farhad Samadzadegan, Farzaneh Dadras Javan Department of Surveying and Geomatics Engineering, University College of Engineering, University of Tehran, Tehran, Iran |
| Abstract: |
| Thermography is a robust method for detecting thermal irregularities on the roof of the buildings as one of the main energy dissipation parts. Recently, UAVs are presented to be useful in gathering 3D thermal data of the building roofs. In this topic, the low spatial resolution of thermal imagery is a challenge which leads to a sparse resolution in point clouds. This paper suggests the fusion of visible and thermal point clouds to generate a high-resolution thermal point cloud of the building roofs. For the purpose, the camera calibration is performed with a mean re-projection error of 0.31 pixels to obtain internal orientation parameters, and then thermal point clouds and visible point clouds are generated. In the next step, both two point clouds are geo-referenced by control points and, they are registered with a mean absolute distance of 0.2 m. To extract building roofs from the visible point cloud, CSF ground filtering is applied and the vegetation layer is removed by RGBVI index. Afterwards, a predefined threshold is applied to the normal vectors in the z-direction in order to separate facets of roofs from the walls. Finally, the visible point cloud of the building roofs and registered thermal point cloud are combined and generate a fused dense point cloud. Results show that the fused point cloud has the spatial accuracy and high density of visible point cloud along with thermal information of the building roofs. |
| Keywords: |
| Thermal Infrared Imaging, Unmanned Aerial Vehicles, Building Roof, Point Cloud Generation, Fusion |
| Status : Conditional Accept (Poster) |
