How do I access detections assigned to a track by TrackerGNN?

I am using "trackerGNN" from the Sensor Fusion and Tracking Toolbox as follows:

 

[confirmedTracks, tentativeTracks, allTracks, analysisInformation] = tracker(detections, T);

I would like to access measurements/detections that have already been assigned to tracks so that I can double check the algorithm's assignments, plot the measurements by track, et cetera. How can I do this?

Answer 1

[MathWorks Support Team]

You can obtain this information by using the output "analysisInformation", which has a property called "Assignments". Hence, "analysisInformation.Assignments" contains the measurements/detections assigned to a track. The format of that field is:

[TrackID DetectionIndex]

The first column is a list of track IDs at the beginning of the step. The second column is the index of the detection that was assigned to this track. For instance, consider the following matrix:

[4 1; 5 3]

This would mean that track 4 was assigned "detections(1)", and track 5 is assigned "detections(3)". Note that the function you are using -- "trackerGNN" -- assigns, at most, a single detection to any track. This is a hard assignment pattern. Other trackers behave differently, so their "analysisInformation" struct will have a slightly different format.