Based the fringe projection profilometry, a compact and flexible positionable measuring head can be combined with optical fiber bundles to perform in-situ inspection tasks in industrial applications. Surfaces of complex geometries can be reconstructed and quantified in metric coordinates by means of a fast, non-contact and high-resolution measurement. Defect segmentation, on the other hand, is rather complex with three-dimensional point clouds, since reference data is required or a deviation determination is ambiguous and susceptible to errors. Due to each reconstructed object point corresponding to a camera pixel, it is possible to apply image processing algorithms or neural networks for defect segmentation. Since image based segmentation is more susceptible to poor illumination and deviating surface curvature or texture, a circular array of miniature LEDs has been coaxially arranged around the imaging optics of the camera’s fiber to provide different illumination directions. By utilizing a directional variable illumination sequence, the advantages of image-based segmentation can be combined with the unambiguousness and metric quantifiability of point cloud data.
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