#8 Introduction to underwater photogrammetry: methods, challenges and applications
Water covers two-thirds of the earth’s surface with an average depth of more than 3500 m and a maximum depth of almost 11000 m (the Mariana Trench), far greater than the highest peak of the world (the mount Everest with nearly 9000 m). With its intrinsic characteristics, water is a naturally unsuitable environment for men, but still, all over the world, an uncountable number of human vestiges exist underwater. Not only archaeological sites, but shipwrecks, ancient and modern, commercial and military, submarines and aircraft. Modern and functioning engineering constructions, such as oil platforms, undersea pipelines, floating wind turbine, etc. are also increasingly populating the ocean. Aquatic ecosystems play a fundamental role in the delicate balance of nature; unraveling their complex and fragile interactions is today more than ever of paramount importance. Consequently, underwater explorations, observations, inspections, and measurements have gained more and more importance and are becoming more common, also pushed by developments in technology, equipment and algorithms.
This tutorial aims at providing the audience with an introduction to the crucial aspects of underwater photogrammetry, as key technique for studying and understanding the underwater world in many application fields, such as exploration and mapping, industry, metrology, archeology, biology, etc.
Specifically, the following topics will be covered:
- Image formation underwater: optical considerations
- Photographic aspects: light absorption, scatter, depth dependent white balance and color correction
- Flat vs Dome ports (from optical to geometric influences in underwater photogrammetry)
- Camera calibration approaches
- Reference systems, accuracy assessment and method of controls (scale bars, underwater geodetic measurements, acoustic positioning systems, pressure sensors)
- Platforms for underwater photogrammetry, from surface vehicles to scuba divers to ROVs and AUVs
- Autonomous navigation and mapping
- Mono, stereo and multi camera systems, laser based optical scaling
- Two media bathymetric photogrammetry
- Overview of applications: needs and approaches in archeology, ecology, metrology and industry.
The attendees will ‘dive’ into the addressed topics and practice with provided datasets, off-the-shelf software applications and in-house developed algorithms. Participants are also encouraged to bring their own datasets, showcase their applications and discuss issues faced in their practices.
Resources that will be distributed: all the teaching material (i.e. the PowerPoint presentations, image datasets, python codes).
Target audience: PhD students, researchers and practitioners
Level: beginner to intermediate