IN-SITU MEASUREMENT OF DIMENSIONS AND SURFACE PROFILE OF AXISYMMETRIC OBJECTS USING FRINGE PROJECTION TECHNIQUE
1 online resource (80 pages) : PDF
University of North Carolina at Charlotte
Fringe projection technique has been a powerful tool for 3D metrology and surface profilometry with high repeatability. However, for in-situ measurement of objects with highly specular surfaces, large dimensions, and large varying slopes, acquiring high precision measurements is a challenge. We developed an inverse projected-fringe technique for in-situ measurement of form and surface profile of axisymmetric parts having those characteristics. A computer simulation-based method, the CAD model and a master-part were used to produce the inverse fringes as well as to find the best measurement trace passing through the symmetrical axis of the part that offers the best signal to noise ratio. This technique measures the deviation from a CAD model or a master-part and provides an accuracy of better than 10 microns for the part with a radial dimension of about 10 cm. It is shown that the proposed technique improves the signal to noise ratio and the repeatability of the system compared to the standard fringe projection technique, in particular for those areas with steep slopes. An in-situ system has been developed for on-machine repeatability and reproducibility tests. The tests showed that the repeatability and reproducibility of the system are still better than 10 microns. Finally, a hybrid method has been used to produce the inverse projected-fringe patterns for the inspection of axisymmetric parts having complex surface structures in addition to large dimensions and large varying slopes.
Fringe ProjectionInverse FringeInverse Projected-FringeOptical MetrologyQuality ControlStructured Light
Optical Science & Engineering
Davies Allen, AngelaPorras-Aguilar, RosarioKazemi, Mohammad
Thesis (Ph.D.)--University of North Carolina at Charlotte, 2018.
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