Ridgely, R. and Witmer, L.: NEW APPLICATIONS OF CT SCANNING AND 3D MODELING FOR DINOSAUR VISUALIZATION

RIDGELY, Ryan, Ohio Univ., Athens, OH; WITMER, Lawrence, Ohio Univ., Athens, OH

The benefits of x-ray CT for revealing internal anatomical features is now well known, as is the ability to reconstruct slices into 3D volumes and surfaces. Both of these will remain indispensable, but a burgeoning new area involves using the resulting 3D digital datasets in novel ways. CT scanning technology and 3D visualization software have developed to the extent that fossils can be “virtually” prepared, restored, manipulated, and interpreted with increasingly high fidelity. New tools allow regions of interest to be digitally extracted (i.e., segmented) based on morphological criteria. For example, matrix-filled spaces within skull bones (e.g., osseous labyrinth; pneumatic, endocranial, and nasal cavities) can be segmented, yielding 3D objects that can be manipulated, measured, and combined. Such segmentation simultaneously results in digital removal of matrix (virtual preparation). CT scanning of isolated elements of a disarticulated Majungatholus skull presented the opportunity to explore methods of reassembly. The separate datasets were loaded into the same 3D environment and then manipulated into articulation. Another method was to scan a previously articulated cast of the whole skull, and then use landmarks to align each element. In this way, anatomical structures segmented in isolated elements (e.g., sinuses, brain cavity) can be visualized together in the complete skull. Excellent scan data were obtained using a conventional medical scanner, but the ear region of the braincase required the increased resolution of microCT. The two datasets were combined and registered using landmarks common to both datasets. Thus, inexpensive medical CT datasets can be integrated with more costly, but anatomically targeted, microCT datasets. Digital methods for the amelioration of the effects of taphonomic distortion (e.g., crushing, plastic deformation) are being explored in a CT dataset of the skull of the giant Paleogene bird Diatryma. The possibility of the full restoration of anatomical relationships remains on the horizon, but landmark-based techniques as well as 3D-warping methods can improve symmetry and approximate the original conformation.