Accuracy Investigations of Image-Matching Methods Using a Textured Dumbbell Artefact in Underwater Photogrammetry

Optical measurement systems are increasingly used for underwater measurement tasks. Whilst 3D object reconstruction based on image-matching methods is established in air and high-quality results can be obtained, accuracy investigations for industrial applications underwater are yet to be carried out. This is because no sufficient reference objects are available. In this master thesis, a new type of textured dumbbell artefact was used as a reference object for the first time to carry out a high-precision verification of an optical measurement system in accordance with VDI Guideline 2634 Part 3 above and underwater. A comparison of the results above and underwater is thus possible, whereby no significant differences in accuracy were found. The distance between measured and calibrated sphere spacing is less than 30 µm in both cases.