Integrated processing of photogrammetric and laser scanning data for frescoes restoration

The integration of photogrammetry and Terrestrial Laser Scanner (TLS) techniques is often desirable for Cultural Heritage digitization, especially when high metric and radiometric accuracy is required, as for the documentation and restoration of frescoed spaces. Despite the many technological and methodological advances in both techniques, their full integration is still not straightforward. The paper investigates a methodology where TLS and photogrammetric data are processed together through an image matching process between RGB panoramas acquired by the scanner’s integrated camera and frame imagery acquired through photographic equipment. The co-registration is performed without any Ground Control Point (GCP) but using the automatically extracted tie points and the known Exterior Orientation parameters of the panoramas (gathered from TLS data original registration) to set the ground reference. The procedure allowed for effective integrated processing with the possibility of take benefit from TLS and photogrammetry pros and demonstrated to be reliable even with low overlap between photogrammetric images.