Create 3D Models of Your Underwater Assets

Friday, February 5, 2021 / The Blueye Office

3D photogrammetry is a great way to get more value out of your drone and allows you to document underwater structures in greater detail. Conducting underwater triangulation is usually more complicated than aerial triangulation, as it is less detailed. However, with a good tool at hand, you can utilize the full potential of your footage. This might sound advanced or somewhat difficult, but with our video tutorial and article, anyone can be guided through the process and become a pro.Combining drone inspections and 3D mapping can provide valuable and more accurate information about your assets' condition. Whether it’s a hull, pipe, marine life, fouling, or damage inspection, 3D modeling can benefit many industries.

Discovering the possibilities

The Blueye team is always exploring new technology and offering our clients the very best service. Throughout the development of our products, we have done extensive ocean testing. Hundreds, if not thousands of hours, have been spent testing, exploring, and documenting different WW2 ship and plane wrecks that lay on the seabed in the Trondheim-region. Inspired by the discovery, our engineers saw the possibility of creating 3D models of underwater structures using photogrammetry. We started testing by capturing detailed footage with the Blueye drone, which was then used to create 3D models of wrecks, geological structures, and marine ecosystems.

For a closer look at the wreck of Short Sunderland and the 3D model our team created, scroll down to the end of the article.

Creating a 3D model using drones

Compiling a 3D model makes it possible to obtain a comprehensive survey of all visible parts of a site and gives a much better overview than the video alone. The detailed information you may otherwise have been oblivious to can be essential in working proactively and taking the right actions at the right time.

Shipping has a great potential for applying this technology.
- Michael Stein, Stein Maritime Consulting.

When capturing images for photogrammetry, you need to see the whole object at once and then move around it to capture it from all angles. The different axis can be defined by maneuvering up and down and then side-to-side of an object at a slow speed. Knowing the depth rate will help in defining the z-axis and contribute to achieving the best result. Such a task can be accomplished in a relatively short period of time and with a high degree of precision. This approach offers specialists and daily users a complete view that can be difficult to capture in 2D due to the underwater environments' murkiness and lack of light. The Blueye drones' ability to get significantly closer to the object than larger equipment, is also perfect for capturing high-quality footage with even lighting and low backscatter.

Micro-ROV systems are very valuable for 3D inspections. [...] The Blueye Pro is the best available product. - Michael Stein, Stein Maritime Consulting

The principle of underwater photogrammetry is the same as that of terrestrial or aerial photogrammetry. But, you have lower clarity and fewer key features under the water, the lighting is changing more, and you typically have some moving particles in the water. All these factors make it more challenging for the software to align the images. In the air, we also have accurate position data from a GPS that helps the software place each image onto the model. Below the surface, this requires costly extra equipment such as a USBL or an LBL system along with a DVL for velocity data, simply because GPS does not work underwater. However, it is fully possible to create smaller models without position data. By utilizing the imu and depth data available from the blueye drone, we greatly help the software sort the images and reduce the computation time.

What makes Blueye more userfriendly in this process, is the ability to export log data, which is time sycronized with any video file. That means you get precoius data such as IMU (roll, pitch, yaw) and depth measurements synced to each video frame automatically. After aligning and collecting the photos, one can easily create a 3D model by running it through specialized software.

Value of using Blueye drones for 3D mapping:

  • Accessibility: Anyone can pilot the Blueye drone with minimal training and collect the necessary footage to create a model.
  • Reach: With a 1000 ft. depth rating, the Blueye Pro drone allows you to explore objects and areas that humans can’t physically reach due to the enormous pressure.
  • Stability: Because of its shape, the drone is highly stable, which provides a steady and smooth motion in the video feed.
  • Mobility: The ability to easily maneuver sideways is crucial when collecting the footage for 3D photogrammetry. The 4 powerful thrusters, as well as the automatic depth and heading controls, let you do this with ease.
  • Camera quality: The success of your 3D mapping is highly dependent on the quality of the pictures. With the full HD tilt camera on the Blueye drone, combined with the excellent light sensitivity, dynamic range, and image stabilization, you can capture high-definition images.
  • Information: The value of information about underwater assets are immense. A three-dimensional model can portray the conditions with higher accuracy than the regular video. With less or poor information, you are at best able to work preventatively. With more information, you can work proactive, giving you a competitive advantage to take corrective action in time.
  • Cost-saving: Instead of spending your budget on hiring divers or ROV pilots, you can use your own drone to conduct the survey and make a stunning 3D model yourself.

Predict break-downs and save money.
- Michael Stein, Stein Maritime Consulting

Greater reward

We are still learning a lot about this fairly unexplored topic of underwater photogrammetry using underwater drones. Things aren’t as straightforward as in the air, but the reward is sometimes much more significant as we can visualize objects from depths that humans can’t physically reach due to the enormous pressure. Therefore, we are excited to help people by offering an easy-to-use tool that can be deployed quickly from a dockside or small boat.

Check out our Sketchfab profile to see all our models.

Looking for more 3D photogrammetry content?

Free Webinar: 3D Photogrammetry Video Tutorial: How to Create a 3D Model Article: How We Capture Footage for 3D Models

Explore further: All you need to know!

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