Semester of Graduation

Spring 2020

Degree

Master of Arts (MA)

Department

Geography & Anthropology

Document Type

Thesis

Abstract

The purpose of this study is to assess whether close-range photogrammetry is a viable alternative to microCT scanning for the construction of 3D models of isolated teeth. Photogrammetric scanning is more cost-effective and less time-consuming than CT scanning, and in paleoanthropological contexts eliminates the possibility of exposing fossils to doses of radiation that affect ESR dating. Samples of fossil (Homo naledi), archaeological, and contemporary human molars were scanned via microCT scanning and close-range photogrammetric scanning. The photogrammetric scans included 96 digital images per tooth which were used to construct a 3D triangular mesh. The resulting models of the tooth crowns were compared to their corresponding CT models using point-to-point surface deviation analysis, which measures the distance between analogous points on each mesh. Surface deviation analysis was also conducted in order to compare the surface difference between the CT meshes before and after processing functions such as smoothing and retriangulation. Paired t-tests comparing the surface difference between processed CT and photogrammetric meshes and the surface difference between processed and unprocessed CT meshes show no significant difference in the level of deviation within the archaeological and contemporary molar samples. A threshold range of acceptable surface difference was devised and applied to the H. naledi sample. A total of 73% of the H. naledi teeth and 70% of all three samples provided photogrammetric meshes that fell into this range of acceptable difference. The majority of molars that fell outside the established range had crown surfaces that were unstained and reflective. The results of this study therefore indicate that close range-photogrammetry provides an accessible alternative to microCT scanning for generating 3D surface models of isolated teeth when sufficient texture and color contrast data is present to aid in photogrammetric scanning accuracy.

Committee Chair

Brophy, Juliet

Available for download on Wednesday, March 15, 2023

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