4D Modelling in Cultural Heritage

This chapter describes the main research outcomes and achievements of 4D modelling in cultural heritage. 4D digital modelling implies the creation of precise time-varying 3D reconstructions of cultural heritage objects to capture temporal geometric variations/distortions, i.e., a spatio-temporal assessment. The key research challenge for 4D modelling, was the data collection over heterogeneous unstructured web resources. Such "in the wild" data include outliers and significant noise, since they have not been created for 3D modelling and reconstruction purposes. In addition, GPS and geo-information is limited or non-existent. However, such data allow for a massive reconstruction of the content even for monuments that have been destroyed due to natural phenomena or humans' interventions. The key outcomes include (i) a Twitter-based 3D modelling of CH objects so as to reconstruct CH monuments and sites from unstructured image content, (ii) the development of a search engine and a (iii) recommendation system for different CH actors (curators, conservators, researchers), (iv) 3D reconstruction of the historic city of Calw in Germany, (v) the creation of a 3D virtual environment in real-time and (vi) launch of a 4D viewer enabling the easy handling of the 3D geometry plus the time. The results show the main innovation of the proposed 4D dimension, i.e., the time in precise modelling of the rich geometric content of the monuments.