3D Underground Mapping with a Mobile Robot and a GPR Antenna

Automatic subsurface mapping is essential in the construction services, as it is anticipated to become the main operational environment of the future robots to be realized in the respective domain. Towards this direction, the paper at hand, introduces for the first time herein, an integrated framework for subsurface mapping by exploiting a surface operating mobile robot with a Ground Penetrating Radar (GPR). The mobile robot tows the GPR antenna, which is mounted on a specifically designed trailer, and is utilized as the mean to cover the surface area, while at the same time the antenna scans the subsurface by emitting electromagnetic pulses. The gathered data are processed for the construction of a subsurface 3D map. Specifically, image processing techniques, that involve background segmentation, HOG [1] feature extraction, hypothesis verification and matching are applied on the 2D radargram (B-Scan) for the detection of the salient points that correspond to buried utilities. By employing the pulse propagation velocity into the subsurface and the soil utilities, the salient points are expressed in world coordinates and used for the composition of the 3D subsurface map. Our method has been evaluated on a real test site, accompanied by ground-truth annotation data of experts and revealed remarkable performance, exhibiting not only the feasibility of underground mapping but also the capacity to obtain exploitable results for underground robotic applications.