SAL settings

In QTM, you can adjust the distances between a trajectory and a skeleton marker for them to be correlated.

1. Open Project Options by clicking the gear icon in the top toolbar or by typing the keyboard shortcut Ctrl+W.

   

2. Navigate to “Processing” à “SAL.”

   

3. Below “Marker to segment marker distance criteria,” two parameters can be customized.

   

4. “Claim threshold” specifies how close a trajectory or trajectory part must get to a segment marker in order for them to be linked. If any frame of a trajectory gets within this range of a segment marker, it will be identified as that marker, unless disqualified.

   

5. “Disqualification threshold” is the maximum distance that any point of a trajectory can get from a segment marker before that trajectory is ruled out as a solution. If any frame of a trajectory is farther from a marker than this value, the trajectory will not be identified with that marker, even if other frames are within the claim threshold. This helps avoid trajectories being mistakenly identified with a segment marker if they get close to one another.

For instance, if an actor puts their hands on their head, the hand trajectories might be within the claim threshold for a head marker, but because the hands also end up farther from the head than the disqualification threshold, they will not be linked.

6. You can change the thresholds depending on your application. For example, shorter distances would be better when tracking fingers.

   

7. Click “OK” to save your settings.

   

Note that to use updated thresholds in a previously recorded file, you will need to reprocess the file, applying the new SAL settings:

1. Click the Reprocessing icon in the top toolbar or type keyboard shortcut Ctrl+Shift+R.

   

2. Make sure that only “Apply SAL” is enabled and that it is using the SAL settings from your project.

   

3. Click “OK” to reprocess the file with the new settings.