Abstract for presentation at Spatial Sciences Institute International Biennial Conference

Cultural heritage features have historically been documented in 2D by painting, photography, lithography etc, and more recently in 3D by photogrammetry and laser scanning. The latter has become very popular for large- and small scale- cultural heritage documentation for the purposes of digital preservation, deformation studies, and modelling for replication. The emerging recording methodology by 3D laser scanning uses multiple instruments to capture details at multiple scales. However, sound procedures for integrating the data from the different data sources and quality assessment of the resulting product do not exist. Even in the academic domain the current procedures are ad hoc and several papers document the failed methodologies used on cultural heritage projects.
The objective of this research project has been to develop the sound framework for such recording schemes for large-scale cultural heritage projects. The presented case study is the Ross Bridge recording project in Tasmania. Spanning the Macquarie River, this sandstone bridge is one of the premier heritage sites in Australia thanks to 186 intricate icons carved by convicts that decorate its arches. These are weathering rapidly and, without conservation, could be lost within 25 years.
This paper will first present an overview of the multi-resolution data collection for the Ross Bridge project, with particular emphasis on the data capture methodologies and technologies used: the Leica HDS2500 and the Vivid 910 scanners. One of the reasons for the aforementioned failed projects was the lack of complete understanding of the error budgets of the scanners used. Therefore, the pertinent outcomes of full error and resolution analyses are described. Finally, results from registration of the multi-resolution dataset ICP registration are presented, which will highlight the achievable outcomes and limitations of such a recording scheme.