Photogrammetry in general is a surveying technique that can be applied as a close-range or as a remote sensing technology. Images of the object of interest are taken from different origins, including so called “identical points”. The reappearance of these identical points in various photographs enables the surveyor to position the photographs in geometrical relation to one another. As when constructing a three-dimensional puzzle, the identical points serve as connection points from one photograph to the next – until the objects is assembled from all perspectives. The result is a 3D-model. The depth (the missing 3rd dimension of a photograph) can be calculated for any pixel in any photograph.
Subsea photogrammetry can only be used as a close range survey, as the visibility doesn’t allow for great distances. However, it is todays most accurate subsea metrology method, when applied for object sizes of more than several meters and up to 150m, like Spool metrologies.
SubseaScanning AS offers consulting services and executes subsea surveys and subsea metrologies using ROVs and divers. Please contact us for more information.