Photogrammetry is the art and science of extracting 3D information from photographs. The process involves taking overlapping photographs of an object, structure, or space, and converting them into 2D or 3D digital models. Using photogrammetry under water is still in an exploratory phase, but the need for accurate, up to date underwater maps and models already exists in certain industries, such as environmental monitoring, archaeology, forensics, and infrastructure inspection. With a measurable 3D model or 2D map of a large area, channels or chambers can be documented for scene reconstruction, habitat protection ; ancient cultural artifacts can be mapped and archived for further research; regions can be repetitively monitored for detecting environmental change and more.
Resolution of the surveying is depending the quality and number of the photos. Moderate object, approx 2 m2, can be made of the highest resolution with 1000+ photos. But processors which are capable of working on this sole task need to be powerful. Our best computer worked for more than 18 hours for only a few meters of channel.
We are preparing to make first full surveying of the longest underwater channel and deepest passed sump in Serbia. This cave is with a long, narrow squeeze which is barely wide for diver to pass, usually with one or both tanks in front. This task will be demanding and will push our limits to the end.