Characterization of Underground Rock Masses Employing Structure from Motion: Application to a Real Case - García Luna, Ramiro; Senent Domínguez, Salvador; Jurado Piña, Rafael y Jiménez Rodríguez, Rafael (Tunnels And Underground Cities: Engineering And Innovation Meet Archaeology, Architecture And Art- Proceedings Of The Wtc 2019 Ita-Aites World Tunnel Congress, 2019)