3D digitizing of large separate artifacts

The article investigates distinctive features of digital photogrammetry and 3D scanning technologies used to create 3D models of large separate artifacts. As an example, the author analyzes the 3D digitizing of a part of the sternpost from a koch, a Russian rowing/sailing boat of the 16th-17th centuries. This ship element was discovered in the hill fort of Mangazeya together with hundreds of other parts. Precise engineering drawings were unknown to Russian boat makers of the 17th century, while the few pictures of the koch and inconsistent written sources do not allow for an authentic reconstruction of all details and specific features of the vessel. The original boat parts discovered during the archaeological studies in Mangazeya, the first transpolar Russian town in Siberia, served the unique resource for the reconstruction. The Artifact Laboratory for Interdisciplinary Archaeological Research of Tomsk State University digitized the whole collection of excavated ship parts in 2014-2015 to preserve them for further investigations. The photogrammetry technology is characterized by low cost and quick data collection. However, the overall data processing may take several times longer than scanning alone. This technology depends heavily on human factors: the right choice of scene modes, photography/camera and software using skills. Besides, background and lighting might need additional processing. The 3D scanning technology is characterized by the high cost of equipment and a rather long process of data collection. Yet, the accuracy of measurements virtually does not depend on human factors; it is guaranteed by the manufacturer and confirmed by relevant certificates. In this case, the author used a GoScan 3D scanner produced by Creaform, a Canadian company. There is also an option of combining these two methods: geometry of the artifact surface is recorded with a 3D scanner, while textures are captured using the digital photo-grammetry technology. This helps achieve the highest possible quality of the model. The choice of a digitizing technology should first of all be determined by the goal researchers pursue. In the given situation, the author focused on the 3D scanning technology to preserve the geometry as much as possible, because the integrity of the wooden ship parts had been gradually damaged. It is also possible to use photogrammetry for maximum precision digitizing, provided that procedures are strictly followed and the right scene modes are selected.

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