Assume objects with IDs 2 and 4 merge. The merged object will then in the next frame(s) have ID 2 and should keep it until it successfully splits up into 2 and 4 again. From my observations, this is not the case for all frames of the merger. To be more specific, the last frame before a merger splits up again is (in my data) always labeled with the next available label in label space.
In one case where 3 objects merged, it was even more confusing: Assume object 2 and 4 merge and the merger carries ID 2 for a couple of frames. It then merges with object 7 and the cluster of three object carries the next available label ID 25. It continues with this ID while object 2 leaves the cluster. Right before splitting up into objects 4 and 7 again, the ID changes to 26. If a merger of two carries the smaller label of the two merged objects, wouldn't it be useful if a merger of 3, 4, N, ... would also carry the label of the smallest of the N merged objects?
Assume objects with IDs 2 and 4 merge. The merged object will then in the next frame(s) have ID 2 and should keep it until it successfully splits up into 2 and 4 again. From my observations, this is not the case for all frames of the merger. To be more specific, the last frame before a merger splits up again is (in my data) always labeled with the next available label in label space.
In one case where 3 objects merged, it was even more confusing: Assume object 2 and 4 merge and the merger carries ID 2 for a couple of frames. It then merges with object 7 and the cluster of three object carries the next available label ID 25. It continues with this ID while object 2 leaves the cluster. Right before splitting up into objects 4 and 7 again, the ID changes to 26. If a merger of two carries the smaller label of the two merged objects, wouldn't it be useful if a merger of 3, 4, N, ... would also carry the label of the smallest of the N merged objects?