Multi-Object Tracking (MOT) requires localizing multiple objects and maintaining their identities over time. Recent query-propagation trackers carry target-specific representations across frames and update them with current-frame image features, yet identity association remains difficult when visually similar targets overlap or cross. During such interactions, current-frame query updates may contain components directed toward nearby active tracks, which may affect identity association in later frames. To investigate this issue, we analyze track-query updates preceding identity switches (IDSWs), where the same target is assigned a different track ID. Our analysis shows that (i) propagated track-query representations change more abruptly before IDSWs, (ii) current-frame updates have larger positive projections along directions toward other active tracks, and (iii) bounding-box intersection over union (IoU) retrieves the counterpart track involved in a subsequent IDSW with high recall when that track remains active before the switch. Motivated by these findings, we propose Test-time Track-Query Calibration (TQC), a training-free and gradient-free method for query-propagation trackers. TQC calibrates the tracker output before propagation using a bounded correction estimated from update components directed toward nearby active tracks. It requires only track-query representations and bounding boxes available during inference, without retraining or architectural modification. Across nine DanceTrack and SportsMOT test settings, TQC improves HOTA and AssA in all settings and IDF1 in eight, with an average HOTA gain of +0.38 and limited inference overhead. Controlled variants on six validation settings further show that TQC's correction direction yields more consistent HOTA improvements than alternative directions with matched correction norms.
Figures & tables
Figure 1: Standard query propagation and Test-time Track-Query Calibration (TQC). Left: A current-frame query update may contain a component directed toward a nearby active-track representation. TQC calibrates the tracker output before propagation using a bounded correction estimated from update components directed toward nearby active tracks. Right: In this example, standard query propagation leads to an identity switch at frame t+1 , whereas TQC preserves the identities.
Figure 2: Distributions of query-update statistics before IDSWs. (a) Norm of the frame-to-frame change in propagated query representations. (b) Average of the five largest normalized positive projections over all other active tracks. (c) Average normalized positive projection over IoU top-5 nearby active tracks.
Figure 3: Candidate retrieval recall for IDSW counterpart tracks. For each evaluated pre-IDSW state in which the counterpart track is active, other active tracks are ranked by bounding-box IoU, query cosine similarity, or the normalized positive projection in Eq. 4 .
Figure 4: Overview of TQC. The upper flow shows the standard query-propagation process, in which track-query representations are updated with current-frame image features and propagated to the next frame. TQC is inserted after the tracker forward pass and calibrates the tracker output representations before subsequent propagation. It retrieves nearby active tracks using bounding-box IoU, estimates update components directed toward these tracks, and subtracts a bounded correction.
Method
HOTA
DetA
AssA
MOTA
IDF1
Deformable:
MOTR
54.21
73.49
40.19
79.68
51.49
+ TQC
54.92
73.79
41.08
80.07
52.30
MeMOTR
63.24
76.95
52.13
85.45
65.43
+ TQC
64.15
77.55
53.24
86.12
66.30
CO-MOT
69.96
82.07
59.78
90.99
72.25
Table 1: Test results on DanceTrack. † DualMOT is evaluated using the publicly released checkpoint without confidence-guided update suppression. Reproduction details are provided in the supplementary material.
Method
HOTA
DetA
AssA
MOTA
IDF1
Deformable:
MeMOTR
68.78
82.01
57.77
90.21
69.89
+ TQC
69.19
82.15
58.36
90.40
70.46
DAB:
MeMOTR
70.00
83.04
59.09
91.46
71.38
+ TQC
70.14
83.14
59.26
91.64
71.53
Table 2: Test results on SportsMOT.
Dataset
Δ HOTA
Δ AssA
Δ IDF1
Pos.
Largest baseline DetA−AssA
DanceTrack
+1.53
+2.03
+1.88
6/6
SportsMOT
+1.07
+1.72
+1.27
3/3
Overall
+1.37
+1.93
+1.68
9/9
Lowest baseline AssA
DanceTrack
+1.40
+1.71
+1.74
6/6
Table 3: Performance on association-hard validation sequences. For each tracker and dataset setting, we independently select ten sequences under each of two baseline criteria. Values are mean TQC improvements across tracker settings, computed from sequence-averaged metrics. Pos. denotes the number of settings with positive Δ HOTA.
Variant
Δ HOTA
Δ AssA
Δ IDF1
Pos.
Full TQC
+0.71
+1.06
+0.88
6/6
Correction direction
Reversed correction
-0.91
-1.28
-1.36
0/6
Random directions
-0.04
-0.05
-0.07
3/6
Orthogonal directions
-0.06
-0.09
+0.02
2/6
Non-overlapping-track directions
+0.10
+0.15
+0.01
4/6
Table 4: Controlled variants on six validation settings. Values are average changes from the corresponding baselines. Pos. denotes the number of settings with positive Δ HOTA. Direction variants preserve the TQC correction norm, and random directions are averaged over eight seeds. Per-setting results are provided in the supplementary material.
Tracker output after TQC
Track query used for propagation
Projection decreased
98.38%
97.21%
Median projection retention
0.317
0.235
Median update-norm retention
0.980
0.792
Table 5: Effect of TQC on query updates. Projection and update-norm retention are state-wise ratios between the TQC branch and the paired branch with the current-frame correction disabled.
Figure 5: Qualitative examples of TQC. Examples from DanceTrack and SportsMOT are shown using MeMOTR-DAB. Values denote the mean normalized positive projection over up to five nearby active tracks with positive bounding-box IoU.
Tracker
Base FPS ↑
+TQC FPS ↑
Slowdown ↓
Test Δ HOTA ↑
MOTR
9.44
9.35
1.02%
+0.71
MeMOTR-Deformable
8.26
8.17
1.13%
+0.91
CO-MOT
9.33
9.26
0.83%
+0.20
MeMOTR-DAB
7.29
7.22
0.95%
+0.41
SambaMOTR-DAB
7.29
7.23
0.91%
+0.32
DualMOT
6.20
6.16
0.61%
+0.20
Table 6: Inference efficiency and HOTA improvements on DanceTrack. Inference speed is measured on the validation set using a DGX Spark, while Δ HOTA denotes the test-set improvement over the corresponding baseline. Slowdown is computed from unrounded per-frame latencies.
Appendix figures & tables20 assets
Supplementary material from the paper’s appendix.
Appendix
Dataset
Tracker
β
ρ
DanceTrack
MOTR [ 37 ]
1.50
0.15
MeMOTR-Deformable [ 10 ]
1.25
0.05
CO-MOT [ 33 ]
1.00
0.10
MeMOTR-DAB [ 10 ]
1.75
0.15
SambaMOTR-DAB [ 25 ]
0.75
0.50
DualMOT † [ 15 ]
2.00
0.25
Appendix
Table 7: Hyperparameters used for test-set evaluation. The parameters are selected using HOTA on the corresponding validation set and fixed for test-set evaluation. † DualMOT uses the publicly released checkpoint without confidence-guided update suppression.
Figure 6: Distributions of query-update statistics before IDSWs with SambaMOTR-DAB. (a) Norm of the frame-to-frame change in propagated track-query representations. (b) Average of the five largest normalized positive projections over all other active tracks. (c) Average normalized positive projection over IoU top-5 nearby active tracks.
All other active tracks
IoU top-5 candidates
Tracker
AUROC
95% CI
AUROC
95% CI
DanceTrack
MeMOTR-Deformable
0.680
[0.625, 0.735]
0.657
[0.615, 0.705]
MeMOTR-DAB
0.699
[0.661, 0.736]
0.682
[0.647, 0.717]
SambaMOTR-DAB
0.691
[0.649, 0.734]
0.666
[0.635, 0.697]
SportsMOT
Appendix
Table 8: AUROC of normalized positive projections after covariance whitening. Results are reported on six validation settings. Brackets indicate 95% confidence intervals obtained from 1,000 sequence-level bootstrap resamples.
Candidate set
Track states
IDSW events
IoU top-5
865/873 ( 99.08% )
405/408 ( 99.26% )
Appendix
Table 9: Coverage of the future IDSW counterpart by the candidate set used by TQC.
Measure
Result
Nonzero counterpart correction term
767/865 ( 88.67% )
Counterpart projection decreased
752/767 ( 98.04% )
Median update-norm retention
0.971
Median counterpart-projection retention
0.378
Appendix
Table 10: Effect of TQC on the update component directed toward the IDSW counterpart.
Representation
Projection decreased
Median projection retention [IQR]
Median update-norm retention [IQR]
Tracker output after TQC
98.38%
0.317[0.109,0.467]
0.980[0.970,0.990]
Track query used for propagation
97.21%
0.235[0.002,0.503]
0.792[0.623,0.920]
Appendix
Table 11: Effect of TQC on candidate-directed projections immediately after TQC and after subsequent query processing. Each percentage is computed over states for which the corresponding paired comparison is defined. Retention values are state-wise ratios reported as medians and interquartile ranges.
Figure 7: Candidate retrieval recall for future IDSW counterparts with SambaMOTR-DAB. For each pre-IDSW state in which the counterpart track is already active, IoU-based retrieval considers only tracks with positive IoU, as in TQC. Query cosine similarity and the normalized positive projection rank all other active tracks.
Δ HOTA
Average
Variant
MeMOTR DAB DT
MeMOTR Def DT
SambaMOTR DAB DT
MeMOTR DAB SP
MeMOTR Def SP
SambaMOTR DAB SP
Δ HOTA
Δ AssA
Δ IDF1
Full TQC
+0.85
+0.96
+0.62
+0.50
+1.22
+0.09
+0.71
+1.06
+0.88
Correction direction
Reversed correction
-2.88
-0.64
-0.52
-0.41
-0.81
-0.20
-0.91
-1.28
-1.36
Random directions
-0.48
+0.27
-0.10
+0.13
+0.11
-0.15
-0.04
-0.05
-0.07
Orthogonal directions
-0.35
-0.31
+0.77
+0.06
-0.22
-0.29
-0.06
-0.09
+0.02
Appendix
Table 12: Controlled variants on six validation settings. Values are changes from the corresponding baseline. Direction variants preserve the TQC correction norm, and random directions are averaged over eight seeds. Norm-preserving correction restores the original update norm, update damping reduces the magnitude of the current-frame query update by the magnitude of the TQC correction, and uniform damping scales continuing-track updates by γ .
Tracker
Base
TQC
Δ
Deformable:
MOTR
2,383
2,330
-53
MeMOTR
1,477
1,378
-99
CO-MOT
1,254
1,184
-70
DAB:
MeMOTR
1,115
1,106
-9
Appendix
Table 13: Identity-switch counts on the DanceTrack test set. Lower values are better. Δ denotes TQC − Base.
Tracker
Base
TQC
Δ
Deformable:
MeMOTR
3,359
3,238
-121
DAB:
MeMOTR
3,393
3,292
-101
SambaMOTR
3,129
2,835
-294
Appendix
Table 14: Identity-switch counts on the SportsMOT test set. Lower values are better. Δ denotes TQC − Base.
Tracker
Metric
Base
TQC
Δ
Deformable:
MOTR
HOTA
51.79
52.77
+0.98
AssA
33.79
34.75
+0.96
IDF1
47.28
48.51
+1.23
MeMOTR
HOTA
47.12
48.68
+1.56
AssA
32.37
34.54
+2.17
Appendix
Table 15: Performance on association-hard DanceTrack validation sequences. For each tracker, we select the ten sequences with the largest values of baseline DetA−AssA . All values are averages of sequence-level metrics. Differences are computed from unrounded values.
Tracker
Metric
Base
TQC
Δ
Deformable:
MeMOTR
HOTA
67.00
68.63
+1.63
AssA
52.39
55.04
+2.65
IDF1
67.15
68.77
+1.62
DAB:
MeMOTR
HOTA
68.18
69.27
+1.09
Appendix
Table 16: Performance on association-hard SportsMOT validation sequences. For each tracker, we select the ten sequences with the largest values of baseline DetA−AssA . All values are averages of sequence-level metrics. Differences are computed from unrounded values.
Tracker
Metric
Base
TQC
Δ
Deformable:
MOTR
HOTA
39.94
40.16
+0.22
DetA
64.29
65.51
+1.22
AssA
25.36
25.15
-0.21
MOTA
66.83
68.49
+1.67
IDF1
37.26
37.56
+0.30
Appendix
Table 17: DanceTrack results using an alternative definition of association-hard sequences. For each tracker, we select the ten validation sequences with the lowest baseline AssA. All values are averages of sequence-level metrics. Differences are computed from unrounded values.
Tracker
Metric
Base
TQC
Δ
Deformable:
MeMOTR
HOTA
65.66
68.12
+2.46
DetA
84.29
84.56
+0.27
AssA
51.33
55.28
+3.96
MOTA
93.10
93.52
+0.42
IDF1
66.29
69.16
+2.87
Appendix
Table 18: SportsMOT results using an alternative definition of association-hard sequences. For each tracker, we select the ten validation sequences with the lowest baseline AssA. All values are averages of sequence-level metrics. Differences are computed from unrounded values.
Tracker
Param.
β
ρ
HOTA
AssA
IDF1
Deformable:
MOTR
β
1.25
0.15
51.85
38.88
49.80
β
1.50
0.15
51.87
38.82
49.80
β
1.75
0.15
51.84
38.77
49.87
ρ
1.50
0.10
51.20
38.11
48.94
ρ
1.50
0.15
51.87
38.82
49.80
Appendix
Table 19: Hyperparameter sensitivity on the DanceTrack validation set. For each tracker, we vary one parameter at a time around the selected value while keeping the other parameter fixed. Best values within each one-parameter sweep are shown in bold.
Tracker
Param.
β
ρ
HOTA
AssA
IDF1
Deformable:
MeMOTR
β
1.25
0.15
75.48
66.66
78.26
β
1.50
0.15
75.65
66.92
78.48
β
1.75
0.15
75.64
66.93
78.46
ρ
1.50
0.10
75.48
66.62
78.22
ρ
1.50
0.15
75.65
66.92
78.48
Appendix
Table 20: Hyperparameter sensitivity on the SportsMOT validation set. For each tracker, we vary one parameter at a time around the selected value while keeping the other parameter fixed. Best values within each one-parameter sweep are shown in bold.
Tracker
Transfer
(β,ρ)
Transferred Δ HOTA
Target-specific Δ HOTA
MeMOTR-Deformable
DT → SP
(1.25, 0.05)
+0.10
+0.41
MeMOTR-DAB
DT → SP
(1.75, 0.15)
+0.10
+0.14
SambaMOTR-DAB
DT → SP
(0.75, 0.50)
+0.19
+0.08
MeMOTR-Deformable
SP → DT
(1.50, 0.15)
+0.88
+0.91
MeMOTR-DAB
SP → DT
(0.75, 0.10)
-0.87
+0.41
SambaMOTR-DAB
SP → DT
(0.50, 0.75)
+0.48
+0.32
Appendix
Table 21: Cross-dataset transfer of TQC hyperparameters on the test sets. DT and SP denote DanceTrack and SportsMOT, respectively. Transferred parameters are selected on the source validation set, whereas target-specific parameters are selected on the target validation set.
Dataset
Method
HOTA
DetA
AssA
MOTA
IDF1
MOT17
MeMOTR-DAB
58.8
59.6
58.4
72.9
71.5
+ TQC
58.8
59.7
58.3
73.0
71.7
MOT20
MeMOTR-DAB
36.8
33.7
40.4
40.6
46.0
+ TQC
37.5
35.1
40.2
42.6
47.4
Appendix
Table 22: Test results on MOT17 and MOT20 with MeMOTR-DAB. Both evaluations use the official MOT17 checkpoint without additional training on MOT20. TQC uses (β,ρ)=(0.75,0.25) , selected on MOT20 train and fixed for both test sets.
Method
mTETA
mHOTA
mLocA
mAssocA
mAssA
MeMOTR-DAB
52.85
40.59
39.63
56.05
52.74
+ TQC
52.90
40.64
39.62
56.28
52.78
Appendix
Table 23: Results on BDD100K validation. All metrics are averaged over eight classes. mAssocA and mAssA are association metrics from TETA and HOTA, respectively.
Tracker
#Q
Params
Base (GFLOPs)
TQC (MFLOPs)
Deformable:
MOTR
2
44.14M
233.28
0.0114
23
44.14M
233.57
1.1305
MeMOTR
2
42.88M
233.28
0.0114
23
42.88M
233.50
1.1275
CO-MOT
6
41.94M
232.04
0.0836
Appendix
Table 24: Computational complexity of TQC. Base denotes the estimated computation of the tracker forward pass, and TQC denotes the additional calibration cost. We follow a common profiling convention that counts each multiply-accumulate as one operation. Here, #Q denotes the number of active track-query slots, and Params denotes the total number of model parameters. TQC introduces no additional learnable parameters.
King Abdullah University of Science and Technology (KAUST), Saudi Arabia · Gaash Research Lab, National Institute of Technology Srinagar, India · The University of Queensland, Australia