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Statistical comparison of three different measurement technologies
Published in Stein Haugen, Anne Barros, Coen van Gulijk, Trond Kongsvik, Jan Erik Vinnem, Safety and Reliability – Safe Societies in a Changing World, 2018
M. Hinz, A. Luecker, B. Bracke, C. Klostermann
Every measurement technology is basically suitable for the measurement of the product geometry but has also various advantages and disadvantages. Structured-light 3D scanner is well qualified for quick measurement of entire geometry but is sensitive for the creation of shades as well as product undercuts. An advantage of coordinate measuring technology is the high measuring accuracy of touched measure points which can be used for calculation and reconstruction of the actual product shape. In contrast, the measuring effort of explicit free-form surfaces is very high, which is a grate disadvantage of this method. Product cavities are measurable only after saw opening of a product in case of both, structured-light 3D scanner and coordinate measuring technology. A CT scan makes use of computer-processed combinations of many X-ray images taken from different angles and allows a survey of undercuts and cavities but cannot be used for all component materials (e.g. lead).
Exploring the capabilities of portable device photogrammetry for 3D surface roughness evaluation
Published in International Journal of Mining, Reclamation and Environment, 2023
Kunze Li, Hamed Lamei Ramandi, Chengguo Zhang, Sarp Saydam, Joung Oh, Serkan Saydam
Scanning dark (black) objects is challenging for the structured light 3D scanner because the black colour does not reflect light to the sensors. In this study, the grey colour of the specimens and constant indoor light sources highly assisted in scanning the surface. Fixing the scanner avoided errors caused by vibration when operated by hand. These measures ensure accuracy but limit their potential for field-scale applications. Rocks are heterogeneous with different colours and maintaining light constantly in practice is not readily achievable, especially in underground excavation engineering. Data transfer and supplying power are other challenges associated with structured light 3D scanners. As shown in Figure 6 and Table 2, portable photogrammetric devices, such as smartphones used in this study, can capture roughness details of lab-scale specimens with relatively comparable accuracy to structured scanners by obtaining images at close distances. The light source requirements of such portable photogrammetric devices are not as limiting as optical scanners. Although no attempts have been made to scan and analyse large-scale rock surfaces with portable photogrammetric devices here, their portability, affordability, and demonstrated accuracy at the lab scale show their potential for industrial applications.
An integrated manifold learning approach for high-dimensional data feature extractions and its applications to online process monitoring of additive manufacturing
Published in IISE Transactions, 2021
Chenang Liu, Zhenyu (James) Kong, Suresh Babu, Chase Joslin, James Ferguson
The aim of this study is to estimate a widely applied surface morphology feature, namely, the surface roughness measurement Sa, by using image patterns. To collect the images and the corresponding surface morphology data (can be quantified using 3D point cloud), a customized structured light 3D scanner, as demonstrated in Figure 14, is utilized (Liu, Law, et al.,2019).