Palaeolithic Archaeology and 3D Visualization Technology: Recent Developments. (News & Notes)
Riel-Salvatore, Julien, Bae, Myungsoo, McCartney, Peter, Razdan, Anshuman, Antiquity
This paper presents computer-aided lithic analysis conducted in the context of an interdisciplinary research framework combining computer science and archaeology--the Partnership for Research in Stereo Modeling (PRISM), at Arizona State University (
The artefacts used in this study are refitted Ahmarian cores collected at Wadi Hasa Locality 623X (Lindly et al. 2000) and curated at Arizona State University. Using previously refitted material allows us to know exactly which pieces refit to which, thereby giving us an external way of testing the results of the refitting software. As well, it provides an estimate of the time involved in doing the refit manually and, by extension, a baseline for how rapid the automatic program would have to be in order usefully to substitute manual efforts.
3D models of those artefacts were created by scanning each piece using a Cyberware M15 or M3030 Laser Digitizer (FIGURE 1). This generates a cloud of points, each of which is defined by x, y, z coordinates. The points are then topologically connected together through the process of triangulation, which results in a `mesh-frame' from which a smooth surface is extrapolated; this system of surface generation is common in computer imaging. The scanned lithics are then imported into Raindrop Geomagic 4.0 to remove noise and unwarranted scanning artefacts. The data are also reduced using polygon decimation to make the models wieldier to analyse.
[FIGURE 1 OMITTED]
Once adequately formatted, a model can be imported into analytical programs developed at the PRISM laboratory (FIGURE 2). The first, feature segmentation software, delineates regions by identifying high and low geometrical points on the model, given a user-specified sensitivity level which can be adjusted to obtain finer or coarser region definition.
[FIGURE 2 OMITTED]
The second program is Region Editor; it permits the merging and splitting of regions originally highlighted by the surface segmentation software to transform them into analytically meaningful surfaces (e.g., a flake's ventral surface). It also allows the user to save these new regions as analytical surfaces which can subsequently be used in the automated refitting process. On top of normal linear measurements (i. …