Presenter: Rachel Glenzer
Mentors: Stephen Frost and Frances White, Anthropology
Poster: 23
Major: Biological Anthropology
We compared the precision of a relatively new method for collecting three-dimensional landmarks, 3D photogrammetry with Agisoft Photoscan, to that of two other well-known methods: Microscribe 3DX and Nextengine Laser Scanner. Landmark editor was used to place landmarks on laser and photoscans. Two crania (one male, one female) of Macaca mulatta from the University of Oregon Comparative Primate Collection were digitized by two users, (RG) and (KC), who each collected 10 replications with all three methods using a well-established 45 landmark protocol. The 120 replications were then analyzed with generalized Procrustes analysis (GPA) in Morpheus with scale restored. An external scale factor was applied to the photoscans to make them consistent. To assess the overall magnitude and patterning of the three different methods, the Principle Component Analysis (PCA) and scores were compared. PC 1 (46 % variance) separated the two specimens. PC 2 (16 % variance) separated the two specimens by user. PC 3 (6 % variance) sorted the Microscribe from the other methods. There is some significant separation within user based on method (P < .0001), but this was much smaller in magnitude than the other factors. Among the three methods, the laser scans had the best precision (0.42 mm), followed by photoscans (0.67 mm), and least precise was microscribe (0.62 mm). Our results indicate that photoscan is as precise as well-known methods.