There are a few ways to make your auto-labelling more reliable in Vicon Nexus 2. We will outline a few ways to perfect your process for auto-labelling.
Do your subject calibration
Our main piece of advice if you are struggling with the auto-labelling functions of Nexus is to ensure you have your subject fully calibrated. This can by done by running the “Auto initialize labeling” pipeline to scale and calibrate the marker layout for the specific subject for more robust labelling.
Alternatively ensure you run the following two operations as part of your subject calibration steps:
- Scale Subject
- Marker-only subject calibration
Offsetting your left and right markers
If you are still having issues with auto-labelling for plug-in-gait, particularly with Nexus discerning the left and right sides of the subject, make sure you have a height offsets/asymmetry between your mid segment markers. This asymmetry helps Nexus discern between the left and right segments when labelling.
The Vicon Nexus Documentation provided by Vicon provides the following locations for the mid segment arm and leg markers:
| Marker label | Definition | Position on patient |
|---|---|---|
| Left lower limb markers | ||
| LTHI | Left thigh | Over the lower lateral 1/3 surface of the left thigh |
| LTIB | Left tibia | Over the lower 1/3 surface of the left shank |
| Right lower limb markers | ||
| RTHI | Right thigh | Over the upper lateral 1/3 surface of the right thigh |
| RTIB | Right tibia | Over the upper 1/3 surface of the right shank |
| Left upper limb markers | ||
| LUPA | Left upper arm | On the upper lateral 1/3 surface of the left arm (Place asymmetrically with RUPA) |
| LFRM | Left forearm | On the upper lateral 1/3 surface of the left forearm (Place asymmetrically with RFRM) |
| Right upper limb markers | ||
| RUPA | Right upper arm | On the lower lateral 1/3 surface of the right arm (Place asymmetrically with LUPA) |
| RFRM | Right forearm | On the lower lateral 1/3 surface of the right forearm (Place asymmetrically with LFRM) |
Remember your Right Back marker
If you are using the Plug-In-Gait full body marker set ensure you remember your right back marker! This marker’s job is to help Nexus discern the left and right side of your subject.
