XR-RF Imaging Enabled by Software-Defined Metasurfaces and Machine Learning: Foundational Vision, Technologies and Challenges - Liaskos, Christos; Tsioliaridou, Ageliki; Georgopoulos, Konstantinos; Morianos, Ioannis; Ioannidis, Sotiris; Salem, Iosif; Manessis, Dionyssios; Schmid, Stefan; Tyrovolas, Dimitrios; Tegos, Sotiris A.; Mekikis, Prodromos-Vasileios; Panagiotis D. Diamantoulakis; et al. (IEEE Access, 2022)