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Evaluate Trackers

Measure tracker quality with standard MOT metrics to get reproducible scores for development and benchmarking.

What you'll learn:

  • Download ground-truth annotations and detections for evaluation
  • Run tracking on pre-computed detections
  • Evaluate tracking results against ground truth

Visualization of ground-truth annotations for MOT17.

Install

Get started by installing the package.

pip install trackers

For more options, see the install guide.

Download Data

Use trackers download to pull ground-truth annotations and detections from supported benchmarks like MOT17.

Fetch MOT17 validation annotations and detections from the command line.

trackers download mot17 \
    --split val \
    --asset annotations,detections \
    --output ./data

Fetch MOT17 validation annotations and detections from Python.

from trackers import Dataset, DatasetAsset, DatasetSplit, download_dataset

download_dataset(
    dataset=Dataset.MOT17,
    split=DatasetSplit.VAL,
    asset=[DatasetAsset.ANNOTATIONS, DatasetAsset.DETECTIONS],
    output="./data",
)

After downloading, your data directory will look like this.

data/
└── mot17/
    └── val/
        ├── MOT17-02-FRCNN/
        │   ├── det/
        │   │   └── det.txt
        │   └── gt/
        │       └── gt.txt
        ├── MOT17-04-FRCNN/
        │   ├── det/
        │   │   └── det.txt
        │   └── gt/
        │       └── gt.txt
        └── ...

For more download options, see the download guide.

Run Tracking

Feed the pre-computed detections into a tracker and write the results to a file for evaluation.

Pass --detections to provide input detections and --mot-output to save the tracker output in MOT format.

trackers track \
    --detections ./data/mot17/val/MOT17-02-FRCNN/det/det.txt \
    --tracker bytetrack \
    --mot-output results/MOT17-02-FRCNN.txt

Evaluate

Compare the tracker output against ground truth to compute standard MOT metrics.

trackers eval \
    --gt ./data/mot17/val/MOT17-02-FRCNN/gt/gt.txt \
    --tracker results/MOT17-02-FRCNN.txt \
    --metrics CLEAR HOTA Identity \
    --columns MOTA HOTA IDF1

Output:

                                MOTA    HOTA    IDF1
----------------------------------------------------
gt                            30.192  35.475  38.515

Data Format

Ground-truth and tracker output files use the MOT Challenge text format.

<frame>,<id>,<bb_left>,<bb_top>,<bb_width>,<bb_height>,<conf>,<x>,<y>,<z>

Example:

1,1,100,200,50,80,1,-1,-1,-1
1,2,300,150,60,90,1,-1,-1,-1
2,1,105,198,50,80,1,-1,-1,-1

Each line contains the frame number, object ID, bounding box (left, top, width, height), confidence score, and 3D position (set to -1 when unused).

Multi-Sequence Evaluation

Evaluate all sequences at once and get per-sequence results plus a combined aggregate.

trackers eval \
    --gt-dir ./data/mot17/val \
    --tracker-dir results \
    --metrics CLEAR HOTA Identity \
    --columns MOTA HOTA IDF1 \
    --output results.json

Output:

Sequence                        MOTA    HOTA    IDF1
----------------------------------------------------
MOT17-02-FRCNN                30.192  35.475  38.515
MOT17-04-FRCNN                48.912  55.096  61.854
MOT17-05-FRCNN                52.755  45.515  55.705
MOT17-09-FRCNN                51.441  50.108  57.038
MOT17-10-FRCNN                51.832  49.648  55.797
MOT17-11-FRCNN                55.501  49.401  55.061
MOT17-13-FRCNN                60.488  58.651  69.884
----------------------------------------------------
COMBINED                      47.406  50.355  56.600

Use --output to save the full results to a JSON file for later analysis.

CLI Reference

All arguments accepted by trackers eval.

Argument Description Default
--gt Path to a single ground-truth file in MOT format. —
--tracker Path to a single tracker predictions file in MOT format. —
--gt-dir Directory containing ground-truth files for multi-sequence evaluation. —
--tracker-dir Directory containing tracker prediction files for multi-sequence evaluation. —
--seqmap Sequence map file listing sequences to evaluate. If omitted, all sequences in the directory are evaluated. all
--metrics Metric families to compute. Options: CLEAR, HOTA, Identity. CLEAR
--threshold IoU threshold for CLEAR and Identity matching. HOTA evaluates across multiple thresholds internally. 0.5
--columns Metric columns to display. If omitted, all columns for the selected metrics are shown. auto
--output Save results to a JSON file at the given path. none