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Using motion capture to track scale models

Qualisys provides solutions for measuring scale models of vessels that helps and aids vessel builders during their development cycle. Even today, builders of large marine vessels will not go directly from design/simulations to production of full scale ships in one step.

By testing a scale model of the vessel and how it behaves under various conditions such as different wave patterns and amplitudes, wind types and water current, information about how the real vessel will perform can be predicted.

A major benefit of using optical motion capture is that it does not require wiring to the vessel during the experiment. Accuracy down to 1mm on position and 0.1° on rotation can be achieved, depending on the capture volume.

Highlighted features

  • Wireless tracking for undisturbed model movement
  • Track several vessels simultaneously
  • Above water: Water resistant IP67 hardware 1
  • Underwater: IP68 housing pressure tested to 40m
  • Active and passive marker support
Marine & Underwater - feature photo

Above water

Water resistant industrial IP67 cameras and cabling means that your motion capture system can be permanently mounted around the tank or basin without the fear of a detrimental splash.

To enable coverage of large ocean basins while maintaining high accuracy, Qualisys has developed a special calibration procedure called fixed- camera calibration. Together with long range active markers, it is possible to track vessels over 100 meters away at frequencies up to 200 fps. The system is equally efficient for the smaller volumes in towing tanks, where the quick dynamic wand calibration is used.

Above water camera systems typically consist of IP67 protected 7+ cameras with optional synchronized and calibrated Miqus Video cameras.

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A Qualisys underwater camera system can be used to track free-running AUVs, underwater objects towed in a towing tank, mooring lines, fish net trawl doors, or oil pipeline motions, just to mention a few.

Large vs. small volumes

Large volume underwater systems are typically made up of 7+u cameras while smaller volumes can be covered with Miqus M3u or M5u cameras.

The 7+ Underwater camera is a robust, high resolution camera for long-range measurements while the Miqus Underwater is a smaller, more lightweight camera with a wide field-of-view, making it well suited for smaller basins and towing tanks in short to medium measurement distances. Synchronized and calibrated Miqus underwater video cameras can be added to both setups, or run as stand-alone reference video cameras to monitor your application

6DOF rigid bodies

Six degrees of freedom (6DOF) position and orientation of the vessel is measured by cameras tracking markers attached to the vessel. Rigid bodies can automatically be identified in real-time by our software.

Real-time SDK

Stream motion data over TCP/UDP to your external application. We have SDKs for C#, C++, Python and provide ready-to-use integrations with for example MATLAB and LabVIEW.

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Combining above and underwater

By combining Qualisys groundbreaking underwater cameras with an above water camera system in what is known as a ‘Twin System’ setup, above- and underwater motion can be merged together into a single capture.

Marine & Underwater - feature photo

Synchronized video

Adding synchronized and calibrated video cameras to both above water and underwater tracking systems is an efficient way to visualize vessel movement by overlaying 3D and 6DOF data onto the image. Alternatively, you may use the video as a standalone reference to monitor applications.