Virtual anthropology (VA): methodological aspects of linear and volume measurements--first results

Virtual Anthropology (VA) is the three-dimensional analysis of anthropological objects within a computer environment. For the investigation of fossil hominid material the VA approach is a very powerful and essential technique to obtain quantitative and qualitative data. The permanent accessibility of the virtual objects and the possibility to study inner structures are striking advantages. The present study is an attempt to evaluate the usefulness and problems of VA and to provide data on accuracy and reproducibility. 10 Homo sapiens skulls were CT-scanned and were measured on the computer and with established methods (calipers and mustard seeds/water displacement). Different co-variables like sex, age, observer, and class and dimension of measurement were included. The results are very promising: The mean of absolute difference for linear measurements is 0.71 mm +/- 0.55 (0.58% +/- 0.49), and 31.59 ccm +/- 13.37 (2.26% +/- 0.86) for volume measurements. Reproducibility is 0.11 mm +/- 0.15 for located landmarks and 0.37 mm +/- 0.41 for relocating landmarks. Age and class of measurement are significant factors.