Scanning the H.L. Hunley: Employing a structured-light scanning system in the archaeological documentation of a unique maritime artifact

Abstract

In 2008, the Warren Lasch Conservation Center acquired a Breuckmann OptoTOP-HE structured-light scanning system to begin the 3D documentation of the American Civil War submarine H.L. Hunley. The choice of this particular system was determined by the interests of the archaeological team and the particular research goals of the project. High resolution 3D surface topography and integrated photographic data were considered equally necessary, suggesting an optical-based scanning system. However, maritime artifacts, or artifacts from a marine environment, are necessarily stored in water or other aqueous solutions prior to completing the conservation process. Using structured-light technology on the H.L. Hunley submarine itself, as well as other artifacts kept in a wet condition, presented the team with some unique difficulties in terms of three-dimensional documentation.This paper will discuss the use of structured-light scanning on the H.L. Hunley, and highlight some of the specific problems and challenges encountered when employing this technology on maritime archaeological material. In particular, we would like to present a brief study of the effectiveness of optical scanning to record surface details, including issues of reflectivity, color, and surface darkness. Moreover, we intend to address the challenges of using the 3D data to reconstruct the submarine into an accurate, color 3D model. It is hoped that this study will both illustrate the problems associated with recording maritime artifacts and suggest further avenues for research and the development of strategies useful for better data collection.