Twin System applications

Twin systems with separate adjacent volumes

Twin systems can be used to combine separate adjacent volumes, for example above and under water, respectively. The Twin System calibration can be used to align the volumes.

Twin systems with separate volumes

Twin systems can be used to combining systems in two rooms, for example for measuring remote coordination tasks. In this case, you can use a manual Twin System calibration to create an arbitrary separation between the volumes, making sure they do not overlap.

Twin systems with a shared volume

Twin systems can be used for two systems with a shared volume. Two examples are:

• Tracking movements at a higher spatial resolution in a sub-volume within a larger volume, for example finger movements of a pianist.

• Capturing fast movements at a higher capture frequency in a sub-volume within a larger volume, for example the head of a golf club during impacts.

For both examples, it is best to use the system covering the sub-volume as the main system as it is prioritized when merging the data.

For the calibration, it is best to place the L-frame in the shared volume so that you can easily merge the data of the two systems. You can then reset the calibration on the Twin System calibration dialog. There can still be a difference in the data of the two systems that is less than a mm. If you find a constant difference you can change the Twin calibration data manually to improve the match. It is not possible to use the automatic Twin calibration.

When merging the data in a shared volume case, it is often best to identify the data in both of the files before merging them in reprocessing, see chapter Processing Twin files. Then if you use the Merge trajectories option the Twin secondary data will be used automatically where the Twin main data is missing. Any labeled Twin secondary data that overlap some Twin main data will be deleted and if you want to use it you have to remove the Twin main data that is wrong and merge the files again.