COMPARISON OF DIGITIZATION TECHNIQUES FOR ICHNOLOGICAL APPLICATIONS

Digitization of modern traces and trace fossils allows quantification of volume, surface area, and a number of metrics that can be used for analyses of ichnotaxonomy, substrate consistency, and bioturbation rates. Multiple digitization methods are available at varying resolutions and costs. The purpose of this project is to compare two digitization methods: Autodesk 123D Catch, a free, photogrammetry-based application, and the NextEngine laser scanner, a costlier, but higher resolution method. The goal of this work is to investigate which methods are most appropriate for particular uses, weighing cost, model properties, and time requirements. Trace fossils and plaster casts of modern traces were digitized with both 123D Catch and the laser scanner. The laser scanner offers a greater amount of versatility in capture settings, but I chose to use relatively low capture resolutions in the interest of reducing scan times. Even at these low resolutions, the laser scanner produced files with average model resolutions about seven times greater than those captured by 123D Catch. Sizes of laser scanner files, however, are typically an order of magnitude greater than 123D Catch files. Volumes and surface areas of traces captured by both methods are typically in very close agreement, with the largest models having the greatest amount of variation; this is likely because small variations in cropping and mesh-filling are magnified in larger models. Capture and processing times vary based on the complexity of the object being digitized. Ultimately, both methods have pros and cons. Both are reliable for capturing volumes and surface areas so 123D Catch may be appropriate when no higher-resolution applications are needed—because the software is free, this method is highly accessible to the geoscience community. Measurements that rely on high fidelity of surface textures are better suited for the laser scanner.