Official Pytorch implementation of the method UNIT. Check out the project website and the article for more details!
UNIT: Unsupervised Online Instance Segmentation through Time, by Corentin Sautier, Gilles Puy, Alexandre Boulch, Renaud Marlet, and Vincent Lepetit
If you use UNIT in your research, please cite:
@article{sautier2025unit,
title = {{UNIT}: Unsupervised Online Instance Segmentation through Time},
author = {Corentin Sautier and Gilles Puy and Alexandre Boulch and Renaud Marlet and Vincent Lepetit},
journal={3DV},
year = {2025}
}
This project has been adapted to SemanticKITTI, nuScenes and PandaSet. Please provide the datasets in the datasets folder, with names in lowercase letters.
UNIT
├── datasets
│ ├── nuscenes
│ │ │── v1.0-trainval
│ │ │── samples
│ │ │── sweeps
│ ├── pandaset
│ │ │── 001
│ │ │── 002
│ │ │── ...
│ ├── semantickitti
│ │ │── sequences
PandaSet does not natively provide instance ground-truth. We provide the code to infer them, independently for the two different Lidar sensors of this dataset, PandarGT and Pandar64. Please run python create_instance_gt_pandaset.py --sensor pandargt to run the pre-processing on PandarGT if you intend to use this dataset.
| SemanticKITTI | non-temporal | temporal |
|---|---|---|
| NuScenes | non-temporal | temporal |
| PandaSet (PandarGT) | non-temporal | temporal |
For SemanticKITTI, you can directly download the pre-processing as re-running Patchwork on your side can be complicated. Alternatively we provide the preprocessing code using Patchwork++, but please note this was not what the article used.
For the other datasets, you must install Patchwork++ and run preprocess_nuscenes.py and preprocess_pandaset.py. This may take several hours, depending on your CPU.
We always start by training the model on a single frame (non-temporal). In the Mask3D directory, run the following commands for respectively SemanticKITTI, PandaSet and nuScenes:
python main_instance_segmentation.py general.experiment_name=sk_single data/datasets=semantic_kitti data.batch_size=3 general.num_frames=1 data.test_batch_size=3 trainer.max_epochs=50
python main_instance_segmentation.py general.experiment_name=pdgt_single data/datasets=pandaset_pandargt data.batch_size=3 general.num_frames=1 data.test_batch_size=3 trainer.max_epochs=150
python main_instance_segmentation.py general.experiment_name=ns_single data/datasets=nuscenes data.batch_size=3 general.num_frames=1 data.test_batch_size=3 trainer.max_epochs=4
To train the temporal models, run the following commands for respectively SemanticKITTI, PandaSet and nuScenes:
python main_instance_segmentation.py general.experiment_name=sk_temporal general.checkpoint=saved/sk_single/last-epoch.ckpt data/datasets=semantic_kitti data.batch_size=4 general.num_frames=2 general.consistency_loss=true data.test_batch_size=4 trainer.max_epochs=50
python main_instance_segmentation.py general.experiment_name=pdgt_temporal general.checkpoint=saved/pdgt_single/last-epoch.ckpt data/datasets=pandaset_pandargt data.batch_size=5 general.num_frames=2 general.consistency_loss=true data.test_batch_size=5 trainer.max_epochs=150
python main_instance_segmentation.py general.experiment_name=ns_temporal general.checkpoint=saved/ns_single/last-epoch.ckpt data/datasets=nuscenes data.batch_size=5 general.num_frames=2 general.consistency_loss=true data.test_batch_size=5 trainer.max_epochs=4
Both for downloaded or trained checkpoints obtaining the checkpoints requires an inference pass.
The command to run the temporal inference on SemanticKITTI is python inference_instance_segmentation.py general.experiment_name=sk_temporal general.checkpoint=saved/sk_temporal/last-epoch.ckpt data.batch_size=1 general.forward_queries=true data/datasets=semantic_kitti data.predict_mode=validation
Adapt options accordingly for other datasets or checkpoints. If you want to infer non-temporal instances, you need to deactive the auto-regressive mechanism using general.forward_queries=false.
Predictions are stored in the assets directory of the dataset and is computed by default for the validation set only.
In the evaluation directory, run python evaluate_4dpanoptic_sk -p ../datasets/semantickitti/assets/sk_temporal or adapt for other datasets or instance predictions.
The evaluation of nuScenes is especially slow, as the optimized version of 4D-PLS produces overflow on this dataset.
To save memory, this code utilizes mixed-precision using bf16, only available for newer hardware. You can add the option "general.precision=32" to the options to deactivate change this behavior, at the cost of higher memory usage.