Research compendium for 'Practical and technical aspects for the 3D scanning of lithic artefacts using micro-computed tomography techniques and laser light scanners for subsequent geometric morphometric analysis. Introducing the StyroStone protocol'
2022-03-18

&lt;p&gt;&lt;strong&gt;Abstract:&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;Here, we present a new method to scan a large number of lithic artefacts using three-dimensional (3D) scanning technology. Despite the rising use of high-resolution 3D surface scanners in archaeological sciences, no virtual studies have focused on the 3D digitization and analysis of small lithic implements such as bladelets, microblades, and microflakes. This is mostly due to difficulties in creating reliable 3D meshes of these artefacts resulting from several inherent features (i.e., size, translucency, and acute edge angles), which compromise the efficiency of structured light or laser scanners and photogrammetry. Our new protocol &lt;em&gt;StyroStone&lt;/em&gt; addresses this problem by proposing a step-by-step procedure relying on the use of micro-computed tomographic technology, which is able to capture the 3D shape of small lithic implements in high detail. We tested a system that enables us to scan hundreds of artefacts together at once within a single scanning session lasting a few hours. As also bigger lithic artefacts (i.e., blades) are present in our sample, this protocol is complemented by a short guide on how to effectively scan such artefacts using a structured light scanner (Artec Space Spider). Furthermore, we estimate the accuracy of our scanning protocol using principal component analysis of 3D Procrustes shape coordinates on a sample of meshes of bladelets obtained with both micro-computed tomography and another scanning device (i.e., Artec Micro). A comprehensive review on the use of 3D geometric morphometrics in lithic analysis and other computer-based approaches is provided in the introductory chapter to show the advantages of improving 3D scanning protocols and increasing the digitization of our prehistoric human heritage.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;Content List:&lt;/strong&gt;&lt;/p&gt; &lt;ul&gt; &lt;li&gt;&lt;strong&gt;S1. &lt;/strong&gt;Step-by-step protocol entitled &lsquo;StyroStone: A protocol for scanning and extracting three-dimensional meshes of stone artefacts using Micro-CT scanners&rsquo;. Also available on protocols.io (dx.doi.org/10.17504/protocols.io.bzbfp2jn);&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S2. &lt;/strong&gt;Dataset with all raw semilandmark coordinate data (in .xlsx format) used in the validation study;&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S3. &lt;/strong&gt;AGMT3D project. The file &ldquo;Validation Protocol-MorphoProject.mat&rdquo; can be used to open the project in the software AGMT3D;&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S4. &lt;/strong&gt;Dataset in .csv format of the principal component score data of the validation study;&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S5.&lt;/strong&gt; R script used to create Figure 2 using the R package ggplot2;&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S6. &lt;/strong&gt;3D models of the experimental bladelets obtained with the Micro-CT scanner used in the validation study. Both .ply and .wrl formats are provided;&lt;/li&gt; &lt;li&gt;&lt;strong&gt;S7. &lt;/strong&gt;3D models of the experimental bladelets obtained with the Artec Micro&nbsp;scanner used in the validation study. Both .ply and .wrl formats are provided.&lt;/li&gt; &lt;/ul&gt;