LTI-UAV3D: a solution of high quality and low cost for terrain 3D reconstruction using a μ-uav

This article describes a simple and quite affordable tool called LTIUAV3D, for terrain three-dimensional reconstruction, using a low-cost unmanned aerial vehicle (UAV) and a personal computer. The 3D model does not require GPS information, because it is built exclusively from monocular images obtained by the onboard camera. To solve the scale factor of the 3D model, an artificial marker is used as a reference, so the obtained height map is metrically precise and correct. An important characteristic of LTIUAV3D is that the 3D model is built in real time, as the UAV flies over the terrain, with incremental updates every second. For the height map obtained, the estimation errors are less than 4%, so the 3D model could be used for path planning and autonomous navigation of UAVs. Also, the LTIUAV3D tool can get a much more precise and detailed 3D model, in an offline process, with height estimation errors less than 1%. This tool makes available, to a large number of users both individuals and academics, a robust foundation for the development of new applications of UAVs.