10 December 1997 Scale artifact length dependence of videogrammetry system uncertainty
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Proceedings Volume 3204, Three-Dimensional Imaging and Laser-based Systems for Metrology and Inspection III; (1997) https://doi.org/10.1117/12.294464
Event: Intelligent Systems and Advanced Manufacturing, 1997, Pittsburgh, PA, United States
Abstract
Testing has shown significant dependence between the length of the scale artifact and the achievable system uncertainty for high accuracy industrial videogrammetry on high aspect ratio objects. Shop practice traditionally allows scale artifacts under 1/5 the object length. This practice can lead to higher than expected uncertainties because the uncertainty of the metric defining the physical scale must be multiplied by the ratio of object length to scale artifact length. This relationship is incorporated into the U95 uncertainty relationship. Test cases validating the uncertainty model are also presented. A network of scale reference points can also be integrated on an object using a laser tracking interferometer. Testing results show a significant reduction in total uncertainties when using this network to define the scale for videogrammetry applications. Measuring a 500-inch (12.7 meters) object and scaling the survey with a 130-inch (3.3 meters), scale bar produced an uncertainty of 22-ppm. When the 500-inch object survey was scaled with laser tracker data, the system yielded an uncertainty of 9-ppm.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Scott C. Sandwith, Scott C. Sandwith, } "Scale artifact length dependence of videogrammetry system uncertainty", Proc. SPIE 3204, Three-Dimensional Imaging and Laser-based Systems for Metrology and Inspection III, (10 December 1997); doi: 10.1117/12.294464; https://doi.org/10.1117/12.294464
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