Studying ancient skeletal populations can present numerous challenges, particularly when bioarchaeologists work with material that is not kept in museums or well-maintained repositories. Preservation issues, access, long-term storage, and general data capture all contribute to the difficulty in studying ancient skeletal material in the field. While methods do exist for extending the use-life of ancient skeletal material beyond the organic lifespan of that material, methods for virtual data capture vary greatly in their ease of use and applicability. It is in the addressing of these issues that the foundation of my current project is situated.
One of the basic tenets of archaeology is preservation. As a destructive discipline, it is incumbent on the archaeologist to do everything within his or her ability to preserve as much of the context of a site as possible, be it through site preservation or materials preservation. We take photos, write copious notes, make maps, and generally document…document, document, document. While all of this documentation is extremely important, not all documentation is equal, nor preserves information in the same manner. In the case of skeletal documentation, we do take photos, and extensive notes on the condition of the material noting any pathological lesions, developmental abnormalities, modifications, evidence of disturbance and so on. A written description, however, only goes so far. Visual documentation is of paramount importance to the preservation of skeletal material and to the ability to continue study of that material after it is no longer available in physical form.
3D imaging provides a means of data capture that far exceeds written description and simple photography alone. As beneficial as having 3D models of skeletal material is, capturing skeletal elements in 3D in field situation presents a myriad of issues. Laser scanning, while generally lauded as the best method for the creation of 3D models due to very high density point cloud generation, is difficult to apply in field contexts, and to skeletal material particularly. Scanners are large, cumbersome and expensive both to procure and insure. In a controlled environment, laser scanning is an ideal method, but for most archaeologists, “ideal” is rarely ever attainable.
So, if laser scanning is taken off the table, what remains? Photogrammetry. Photogrammetry calculates measurements from photographs. Unlike a laser scanner which generates point clouds based on light reflection, photogrammetry relies on triangulation of points from overlapping images. The point clouds are generated to create a 3D model of an object, in this case skeletal material, from a series of high resolution images taken around the object. While some might consider photogrammetry less sophisticated than laser scanning, and in fact it is, in its own way, rather cumbersome (particularly with regard to storing large image files in large quantities), it is also a much more portable method of generating 3D models. The field equipment necessary undertake the creation of 3D models with photogrammetry can generally be found in most archaeologists’ tool kits: a camera. For simple model creation, even a good quality point-and-shoot or mobile phone camera can work.
This project, specifically, is going to utilize DSLR and very high resolution images to create models of skeletal material in order to generate a best-practices model for other bioarchaeologists to utilize in their own field work. The aim is to standardize a method which can be easily implemented in any archaeological setting to capture more data from skeletal material than simple description and basic photography alone can capture.
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