Integrating Multiband Photogrammetry, Scanning, and GPR for Built Heritage Surveys: The Façades of Castello del Valentino

The conservation of built heritage is a complex process that necessitates co-operative efforts. Holistic, integrated documentation constitutes a crucial step towards conservation by contributing to diagnosis and by extension to the effective decision-making about the required preventive and restorative interventions. It involves the recording of interdisciplinary data to produce objective diagnostical conclusions concerning the state of preservation. Although the developments in close-range sensing techniques allow increasingly accurate and rich data recording for heritage building condition surveys, the problem of combining them (to allow integrated processing) often remains unsolved. This is particularly true when surveys include vastly heterogenous documentation data. This work aims to discuss methodologies and implications of such integrations through a monumental heritage survey case—the Castello del Valentino in Turin (Italy). Visible-spectrum and infrared imagery is combined with photogrammetric techniques, terrestrial LiDAR, and microwave measurements conducted on the historical façades’ surfaces, to examine the comprehensiveness of the data fusion results, as well as conclusions that can be drawn regarding previous interventions and the current condition of the monument.