Graphical refinement of a seafloor photomosaic generated from an AUV navigation model

A set of Matlab tools were developed to create seafloor mosaics from AUV photosurveys. The resulting mosaic products are used to guide instrument placement, ground-truth acoustic backscatter targets, and inspect sensor packages or other targets. Because of the positional sensitivity of these tasks, effort has been made to preserve the geographic distribution of the image content. After initial image preprocessing, the images are combined with vehicle navigation. Sensor offsets can be assessed graphically and corrected as necessary. Control points observed between images are used to compute an updated navigation model, and the resulting corrected navigation can be used for multibeam processing and further mosaic processing. An additional utility was developed to use the corrected navigation as a starting point for a graphical refinement of the mosaic data. Automatic feature matching is applied to find additional connections between neighboring images, and the resulting ties are used to adjust image placement. Limits are imposed to prevent false matches from shifting images from their geographic references. At any step of the process, a mosaic can be exported in GeoTIFF format for input into GIS software.