To use eye vector data, you will normally want to export both the eye vector data itself and the Head and Tracker data (the segment data) that relates the eye vector to its position within the global coordinate system. To export all the information relating to the eye vector, you must reconstruct and label the trial and kinematically fit the data before exporting it.
To export eye vector data and segment data:
- Load into Vicon Nexus the trial from which you want to export eye tracking data.
- On the System tab of the Resources pane, click the Dikablis Eye Tracker node to select it.
- To check that the eye vector data is included, open a Graph view pane and observe the eye vector x and y values.Tip
You can export the eye vector data at this point, but the exported file will not include the segment data, which is necessary to position the eye vector within the global coordinate system.
- Run Reconstruct and Label, either by clicking the Reconstruct and Label button on the Nexus toolbar or by running the Reconstruct and Label pipeline in the Pipeline Tools pane.
In the 3D Perspective view, as processing proceeds, you can see first the addition of the object markers and then the labeling.
- After labeling is complete, to see and use the eye vector, you need to kinematically fit the data. To do this, run Kinematic Fit, either by clicking the KinFit button on the Nexus toolbar or by running the Kinematic Fit pipeline in the Pipeline Tools pane, making any changes necessary in the Properties pane.Tip
To produce the required result, you may need to reduce the Prior Importance to zero.
- Run the Kinematic Fit operation.
The eye vector is displayed in the 3D Perspective view.
- In the Pipeline Tools pane, expand File Export, then double-click Export ASCII.
- In the Properties pane, in the Segments section, change the Global Angle setting to All.
- Run the Export ASCII pipeline operation.
To see the exported data, on the Data Management tab, with the relevant trial selected, click on the hyperlink at the bottom and double-click the relevant .csv file to open it.
The eye vector data is displayed as a unit vector in the columns headed RayX, RayY, and RayZ.
The units are between 1000 and -1000 mm. The eye vector data is local to the segment to which the eye tracker is connected (ie, the Head). Both the eye vector data and the Head and Tracker (and Wand) data are exported.
- To position the eye vector in global coordinate space, use the Head and Tracker data. To ensure accuracy, also apply the offset from the Head segment. To find the offset, in the System Resources pane, click the Dikablis Eye Tracker node and in the Properties pane, go to the Eye Offset coordinates.
- When you save, kinematic data is not saved, so to preserve kinematics, rerun Kinematic Fit.