Statistical Comparison between Low-Cost Methods for 3D Characterization of Cut-Marks on Bones

In recent years, new techniques for the morphological study of cut marks have become essential for the interpretation of prehistoric butchering practices. Different criteria have been suggested for the description and classification of cut marks. The methods commonly used for the study of cut marks rely on high-cost microscopy techniques with low portability (i.e., inability to work in situ), such as the 3D digital microscope (3D DM) or laser scanning confocal microscopy (LSCM). Recently, new algorithmic developments in the field of computer vision and photogrammetry, have achieved very high precision and resolution, offering a portable and low-cost alternative to microscopic techniques. However, the photogrammetric techniques present some disadvantages, such as longer data collection and processing time, and the requirement of some photogrammetric expertise for the calibration of the cameras and the acquisition of precise image orientation. In this paper, we compare two low-cost techniques and their application to cut mark studies: the micro-photogrammetry (M-PG) technique presented, developed, and validated previously, and a methodology based on the use of a structured light scanner (SLS). A total of 47 experimental cut marks, produced using a stainless steel knife, were analyzed. The data registered through virtual reconstruction was analyzed by means of three-dimensional geometric morphometrics (GMM).