Mapping underwater ship hulls using a model-assisted bundle adjustment framework

In addition, the precision of our bundle adjustment framework allows the identification of structural deviations between 3D structure inferred from bundle-adjusted camera imagery and the prior model. These structural deviations are clustered into shapes, which allow us to fuse camera-derived structure back into the 3D mesh. This augmented model can be used within a 3D photomosaicing pipeline, providing a visually intuitive 3D reconstruction of the ship hull. We evaluate our pipeline using the Bluefin Robotics hovering autonomous underwater vehicle (HAUV) surveying the SS Curtiss, where a 3D mesh derived from computer aided design (CAD) drawings serves as the prior model. In addition to more consistent visual reconstructions, we can update the prior mesh with 3D information corresponding to underwater structure, such as biofouling or manually-placed cylindrical shapes with known dimensions.