Track IDs that swap when objects cross
The problem
In crowded video, two pedestrians walk past each other or a car disappears behind a bus. When they reappear, the old ID ends up on the wrong object, or a fresh ID is started. Every frame still “looks” labelled, but the model is now learning broken identities.
Identity switches are a core error type in the standard tracking metrics (CLEAR MOT, IDF1, HOTA). One swap mid-sequence damages every frame after it, not just one frame.
Why it happens
- Linear interpolation between keyframes cannot follow two objects that cross paths.
- Annotators work frame by frame and rarely re-check identity after an occlusion.
- QA that samples random frames almost never lands on the few frames where the swap happens.
How Lakspire handles it
Occlusion-aware guideline
IDs persist through occlusion for up to 60 frames. Re-identification uses both appearance and trajectory, and that rule is written down.
Denser keyframes where it is crowded
Segments with many overlapping boxes switch from 10-frame to 2-frame keyframing, so interpolation is never trusted across a crossing.
Crossing-event review queue
A script flags every frame where two tracks overlap (IoU > 0.3). A senior reviewer confirms identities before and after each event.
Trajectory continuity check
Sudden jumps in velocity or box size are flagged automatically. That is the usual sign of an ID landing on the wrong object.
Score before delivery
A gold sequence is scored with TrackEval (IDF1, HOTA, ID switches). The batch ships only if it meets the agreed threshold.
≤ 2
ID switches / 1k track-frames
≥ 0.95
IDF1 on gold sequence
100%
Crossing events reviewed
What you receive
MOTChallenge-format tracks, a crossing-event log, and a TrackEval score sheet per batch.
