Sea Technology

SEP 2017

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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www.sea-technology.com September 2017 / st 31 the relative positions of flanges that could be separated by a certain distance and have relative orientation angles. A photogrammetry survey simply requires flying from one flange to the other in a back-and-forth motion to mini- mize errors, then recording the corresponding HD video file. Images are extracted from the video for 3D process- ing, and the output is a 3D as-built CAD model that can be used for the design of the new spool, with the guarantee that it will fit perfectly. It is also possible for quality-check purposes to superimpose the CAD model on any picture of the same area previously corrected of all optical distortions. Manifold. Like spool metrol- ogy, flying around a manifold with an HD camera allows the creation of a very accurate 3D as-built CAD model of the entire manifold. The standard achievable accuracy is 1/2,000 (i.e., 1-mm on 2-m dimensions), and this can be made even higher to fit the client's needs. Flex Joint. Since the surface of a flex joint consists of black rub- ber, it is only possible to measure a few points by photogrammetry, which are not enough to create an accurate and dense mesh. DimEye's VLS technology was initially developed for flex joint 3D modeling. The VLS includes an HD camera and a laser plane pro- jector. Three-hundred-and-sixty images (one every degree) are extracted for the 3D model, and in case of anomalies, additional images (and, therefore, laser lines) can be extract- ed, which will locally generate an even more dense point cloud. Pipe Dent. Pipe Dent 3D measurement is the most straightforward application of the VLS technology: Scanning the dent through a single run generates a very accurate point cloud that can later be used for analyzing the dent's dimen- Sample VLS survey and 3D analysis of subsea piles.

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