MoCoV2¶

Improved Baselines with Momentum Contrastive Learning

Abstract¶

Contrastive unsupervised learning has recently shown encouraging progress, e.g., in Momentum Contrast (MoCo) and SimCLR. In this note, we verify the effectiveness of two of SimCLR’s design improvements by implementing them in the MoCo framework. With simple modifications to MoCo—namely, using an MLP projection head and more data augmentation—we establish stronger baselines that outperform SimCLR and do not require large training batches. We hope this will make state-of-the-art unsupervised learning research more accessible.

How to use it?¶

from mmpretrain import inference_model

predict = inference_model('resnet50_mocov2-pre_8xb32-linear-steplr-100e_in1k', 'demo/bird.JPEG')
print(predict['pred_class'])
print(predict['pred_score'])

import torch
from mmpretrain import get_model

model = get_model('mocov2_resnet50_8xb32-coslr-200e_in1k', pretrained=True)
inputs = torch.rand(1, 3, 224, 224)
out = model(inputs)
print(type(out))
# To extract features.
feats = model.extract_feat(inputs)
print(type(feats))

Prepare your dataset according to the docs.

Train:

python tools/train.py configs/mocov2/mocov2_resnet50_8xb32-coslr-200e_in1k.py

Test:

python tools/test.py configs/mocov2/benchmarks/resnet50_8xb32-linear-steplr-100e_in1k.py https://download.openmmlab.com/mmselfsup/1.x/mocov2/mocov2_resnet50_8xb32-coslr-200e_in1k/resnet50_linear-8xb32-steplr-100e_in1k/resnet50_linear-8xb32-steplr-100e_in1k_20220825-994c4128.pth

Models and results¶

Pretrained models¶

Model	Params (M)	Flops (G)	Config	Download
`mocov2_resnet50_8xb32-coslr-200e_in1k`	55.93	4.11	config	model \| log

Image Classification on ImageNet-1k¶

Model	Pretrain	Params (M)	Flops (G)	Top-1 (%)	Config	Download
`resnet50_mocov2-pre_8xb32-linear-steplr-100e_in1k`	MOCOV2	25.56	4.11	67.50	config	model \| log

Citation¶

@article{chen2020improved,
  title={Improved baselines with momentum contrastive learning},
  author={Chen, Xinlei and Fan, Haoqi and Girshick, Ross and He, Kaiming},
  journal={arXiv preprint arXiv:2003.04297},
  year={2020}
}