A Comparison of Close-Range Photogrammetry to Terrestrial Laser Scanning for Heritage Documentation
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2013
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South African Journal of Geomatics
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University of Cape Town
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Abstract
This paper describes the photogrammetric and laser scan survey of an excavated section of the Laetoli hominid track-way in Tanzania. The survey was designed to allow for comparison to a prior detailed survey of the track-way carried out in 1995, and serves as a means to compare terrestrial laser scanning with close-range photogrammetry as survey methods for heritage documentation. Each hominid footprint in the track-way was photogrammetrically recorded using a rigorous multi-image controlled configuration. In a separate process a laser scanner was used to scan the entire track-way as well as the individual footprints. The data for the comparison and track-way / footprint shape assessment were a photogrammetrically generated point cloud and a 3D model (established in 1995 and 2011), as well as a laser scan point cloud acquired in the 2011 survey. The results showed a high agreement between the laser scan and the photogrammetric data captured in 2011. These two survey processes are entirely independent of each other, the results can be accepted as entirely objective and the excellent agreement between the data can serve as quality control, confirming that the footprint point clouds were captured with an external accuracy of approximately 0.3 to 0.4mm. Standard deviations which are internal precision measures, and typically optimistic, show an individual point accuracy of 0.1 to 0.2 mm. The accuracy for the full laser scan track-way survey was in the order of 1mm.
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Rüther, H., Smit, J., & Kamamba, D. (2012). A comparison of close-range photogrammetry to terrestrial laser scanning for heritage documentation. South African Journal of Geomatics, 1(2), 149-162.