Towards the definition of best 3D practices in archaeology: Assessing 3D documentation techniques for intra-site data recording

Archaeology is becoming increasingly ‘digital’. In the last 10 years, the use of 3D technologies for the documentation of tangible cultural heritage has changed the way to approach archaeological intra-site survey. These technologies allow for the reproduction of 3D replicas of sites and monuments and have proven to be a powerful tool for the documentation and preservation of the archaeological record. However, the full integration of 3D technologies in archaeological field methods requires the definition of best documentation practices and methods of accurate assessment of the acquired data. In fact, although the use of 3D laser scanners, computer vision and photogrammetric methods is now well established, there are no convincing quantitative comparisons between laser scanning and image-based modelling techniques for the acquisition of archaeological stratigraphy in extreme environmental and lighting conditions. In this sense the 3D documentation of the archaeological site of Las Cuevas, Belize, represented an important opportunity to test and compare phase shift variation laser scanning and image-based modelling techniques in an environment characterized by very high humidity and variability in lighting. This study compared both the accuracy and density reliability of 3D models showing how the different 3D documentation techniques can be integrated for the recording of the excavation process. The research presented in this paper provides an accurate data assessment representing a concrete starting point for the definition of a sharable and overall methodology that will help to define best 3D practices for the documentation of archaeological sites.