CenterMask2 is an upgraded implementation on top of detectron2 beyond original CenterMask based on maskrcnn-benchmark.


  • First anchor-free one-stage instance segmentation. To the best of our knowledge, CenterMask is the first instance segmentation on top of anchor-free object detection (15/11/2019).
  • Toward Real-Time: CenterMask-Lite. This works provide not only large-scale CenterMask but also lightweight CenterMask-Lite that can run at real-time speed (> 30 fps).
  • State-of-the-art performance. CenterMask outperforms Mask R-CNN, TensorMask, and ShapeMask at much faster speed and CenterMask-Lite models also surpass YOLACT or YOLACT++ by large margins.
  • Well balanced (speed/accuracy) backbone network, VoVNetV2. VoVNetV2 shows better performance and faster speed than ResNe(X)t or HRNet.


  • CenterMask2 has been released. (20/02/2020)

Results on COCO val


We measure the inference time of all models with batch size 1 on the same V100 GPU machine.

  • pytorch1.3.1
  • CUDA 10.1
  • cuDNN 7.3
  • multi-scale augmentation
  • Unless speficified, no Test-Time Augmentation (TTA)


Method Backbone lr sched inference time mask AP box AP download
Mask R-CNN (detectron2) R-50 3x 0.055 37.2 41.0 model | metrics
Mask R-CNN (detectron2) V2-39 3x 0.052 39.3 43.8 model | metrics
CenterMask (maskrcnn-benchmark) V2-39 3x 0.070 38.5 43.5 link
CenterMask2 V2-39 3x 0.050 39.7 44.2 model | metrics
Mask R-CNN (detectron2) R-101 3x 0.070 38.6 42.9 model | metrics
Mask R-CNN (detectron2) V2-57 3x 0.058 39.7 44.2 model | metrics
CenterMask (maskrcnn-benchmark) V2-57 3x 0.076 39.4 44.6 link
CenterMask2 V2-57 3x 0.058 40.5 45.1 model | metrics
Mask R-CNN (detectron2) X-101 3x 0.129 39.5 44.3 model | metrics
Mask R-CNN (detectron2) V2-99 3x 0.076 40.3 44.9 model | metrics
CenterMask (maskrcnn-benchmark) V2-99 3x 0.106 40.2 45.6 link
CenterMask2 V2-99 3x 0.077 41.4 46.0 model | metrics
CenterMask2 (TTA) V2-99 3x - 42.5 48.6 model | metrics
  • TTA denotes Test-Time Augmentation (multi-scale test).


Method Backbone lr sched inference time mask AP box AP download
YOLACT550 R-50 4x 0.023 28.2 30.3 link
CenterMask (maskrcnn-benchmark) V-19 4x 0.023 32.4 35.9 link
CenterMask2 V-19 4x 0.023 32.8 35.9 model | metrics
YOLACT550 R-101 4x 0.030 28.2 30.3 link
YOLACT550++ R-50 4x 0.029 34.1 - link
YOLACT550++ R-101 4x 0.036 34.6 - link
CenterMask (maskrcnn-benchmark) V-39 4x 0.027 36.3 40.7 link
CenterMask2 V-39 4x 0.028 36.7 40.9 model | metrics
  • Note that The inference time is measured on Titan Xp GPU for fair comparison with YOLACT.


All you need to use centermask2 is detectron2. It's easy!
you just install detectron2 following
Prepare for coco dataset following this instruction.


ImageNet Pretrained Models

We provide backbone weights pretrained on ImageNet-1k dataset.

To train a model, run

cd centermask2
python --config-file "configs/<config.yaml>"

For example, to launch CenterMask training with VoVNetV2-39 backbone on 8 GPUs,
one should execute:

cd centermask2
python --config-file "configs/centermask/centermask_V_39_eSE_FPN_ms_3x.yaml" --num-gpus 8


Model evaluation can be done similarly:

  • if you want to inference with 1 batch --num-gpus 1
  • --eval-only
  • MODEL.WEIGHTS path/to/the/model.pth
cd centermask2
python --config-file "configs/centermask/centermask_V_39_eSE_FPN_ms_3x.yaml" --num-gpus 1 --eval-only MODEL.WEIGHTS centermask2-V-39-eSE-FPN-ms-3x.pth


  • [ ] Adding Lightweight models
  • [ ] Applying CenterMask for PointRend or Panoptic-FPN.

Citing CenterMask

If you use VoVNet, please use the following BibTeX entry.

  title = {An Energy and GPU-Computation Efficient Backbone Network for Real-Time Object Detection},
  author = {Lee, Youngwan and Hwang, Joong-won and Lee, Sangrok and Bae, Yuseok and Park, Jongyoul},
  booktitle = {Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition Workshops},
  year = {2019}

  title={CenterMask: Real-Time Anchor-Free Instance Segmentation},
  author={Lee, Youngwan and Park, Jongyoul},
  journal={arXiv preprint arXiv:1911.06667},