Applying 3d and photogrammetric scanning systems to the case of cultural heritage

In the context of the preservation of cultural heritage, the new technologies available to operators in the sector, allow the use of increasingly efficient non-invasive diagnostic techniques, aimed mainly to identify the processes of degradation, to be understood as loss of performance or initial properties produced over the years, due to natural or artificial causes. Today, the available techniques allow the generation of 3D models from images made with common digital cameras that, through the use of dedicated software, based on “Structure from Motion” (SfM) algorithms and DEM (Digital Elevation models Model) of high quality, allow the high-resolution reconstruction of the object in order to acquire elements useful to the interpretation of the deterioration in progress, without damaging the state of the work investigated. The above techniques can be used to determine external morphology, to search for defects of homogeneity and to survey lesions. There is no doubt that careful visual analysis is the basis for a proper assessment of the condition of the work under investigation. However, only the visual examination is not sufficient to provide the information necessary to make a correct diagnosis, therefore, the application of the above techniques, allows to thoroughly investigate the phenomena of failure, also going back to their causes. In this work, SfMs and DEMs are applied in the field of cultural heritage and the results are compared with those obtained from laser scanning acquisitions in order to acquire all the necessary information for subsequent evaluations and comparisons.