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Tracking parameter values for a sparse 35-marker set
The following illustration shows a sparse marker set consisting of 35 facial markers.
The suggested tracking parameters for this marker set are given below, with the three suggested changes from the default settings highlighted in yellow:
|
Tracking parameter |
Value |
|
Patch Match Threshold |
0.8 |
|
Face Point Tracking Distance |
35 pixels |
|
Face Point Max Elastic Prediction Distance |
25 pixels |
|
Brim Point Tracking Distance |
15 pixels |
|
Patch Match Size |
15 pixels |
|
Remove Bad 2D Projections |
True |
|
Max Allowed 2D Projection Error |
5 pixels |
|
Remove Bad 3D Points |
True |
|
Max Allowed 3D Point Error |
10mm |
|
Allow Single Sensor Tracking |
False |
|
Single Sensor Tracking Threshold |
0.5mm |
|
Blob Size Difference Threshold |
0.75 |
For this more sparse facial marker set, it is advisable to relax a couple of tracking parameter values to reflect the fact that the facial markers are more widely spaced, and thus the tracking elastic prediction algorithm, which makes use of the relationships between neighboring marker points, will be less accurate. You should therefore relax both the Face Point Max Elastic Prediction Distance and Max Allowed 3D Point Error parameters, and also (probably) turn off Single Sensor Tracking, which also relies upon the accuracy of the elastic prediction algorithm.