Boosting Pixel-Wise Contrastive Learning with Probabilitic Representations (AAAI 2023)

This repository contains the source code of PRCL from the paper Boosting Pixel-Wise Contrastive Learning with Probabilitic Representations.

In this paper, we redefine the representation in pixel-wise contrastive learning from a perspective of probability theory. We consider the probability and model the representation as random variable, namely Probabilistic Representation.

Updates

Nov. 2022 -- Upload the sorce code.

Prepare

PRCL is evaluated with two datasets: PASCAL VOC 2012 and CityScapes.

• For PASCAL VOC, please download the original training images from the official PASCAL site: VOCtrainval_11-May-2012.tar and the augmented labels here: SegmentationClassAug.zip. Extract the folder JPEGImages and SegmentationClassAug as follows:

├── data
│   ├── VOCdevkit
│   │   ├──VOC2012
│   │   |   ├──JPEGImages
│   │   |   ├──SegmentationClassAug

• For CityScapes, please download the original images and labels from the official CityScapes site: leftImg8bit_trainvaltest.zip and gtFine_trainvaltest.zip. Extract the folder leftImg8bit_trainvaltest.zip and gtFine_trainvaltest.zip as follows:

├── data
│   ├── cityscapes
│   │   ├──leftImg8bit
│   │   |   ├──train
│   │   |   ├──val
│   │   ├──train
│   │   ├──val

Folders train and val under leftImg8bit contains training and validation images while folders train and val under leftImg8bit contains labels.

The data split folder of VOC and CityScapes is as follows:

├── VOC(CityScapes)_split
│   ├── labeled number
│   │   ├──seed
│   │   |   ├──labeled_filename.txt
│   │   |   ├──unlabeled_filename.txt
│   │   |   ├──valid_filename.txt

You need to change the name of folders (labeled number and seed) according to your actual experiments.

PRCL uses ResNet-101 pretrained on ImageNet and ResNet-101 with deep stem block, please download from here for ResNet-101 and here for ResNet-101 stem. Remember to change the directory in corresponding python file.

In order to install the correct environment, please run the following script:

conda create -n prcl python=3.8.5
conda activate prcl
pip install -r requirements.txt

It may takes a long time, take a break and have a cup of coffee! It is OK if you want to install environment manually, remember to check CAREFULLY!

Run

You can run our code with a single GPU or multiple GPUs.

• For single GPU users, please run the following script:

python prcl_sig.py [--config]

You need to change the file name after --config according to your actual experiments.

• For multiple GPUs users, please run the following script:

run ./script/batch_train.sh

We provide 662 labels for VOC and 150 labels for CityScapes, the seed in our experiments is 3407. You can change the label rate and seed as you like, remember to change the corresponding config files and data_split directory.

Hyper-parameters

All hyper-parameters used in the code are shown below:

Name	Discription	Value
alpha	hyper-parameter in EMA model	0.99
lr	learning rate of backbone, prediction head, and project head	3.2e-3
uncer_lr	learning rate of probability head	5e-5
un_threshold	threshold in unsupervised loss	0.97
weak_threshold	weak threshold in PRCL loss	0.7
strong_threshold	strong threshold in PRCL loss	0.8
temp	temperature in PRCL loss	100
num_queries	number of queries in PRCL loss	256
num_negatives	number of negatives in PRCL loss	512
begin_epoch	the begin epoch of scheduler $\lambda_c$	0
max_epoch	the end epoch of scheduler $\lambda_c$	200
max_value	the max value of scheduler $\lambda_c$	1.0
min_value	the min value of scheduler $\lambda_c$	0
ramp_mult	the $\alpha$ of scheduler $\lambda_c$	-5.0

It is worth noting that uncer_lr is very sensitive and training may crash if uncer_lr is not fine-tuned CAREFULLY.

Acknowledgement

The data processing and augmentation (CutMix, CutOut, and ClassMix) are borrowed from ReCo.

• ReCo: https://github.com/lorenmt/reco

Thanks a lot for their splendid work!

Citation

If you think this work is useful for you and your research, please considering citing the following:

@article{PRCL,
  title={Boosting Semi-Supervised Semantic Segmentation with Probabilistic Representations},
  author={Xie, Haoyu and Wang, Changqi and Zheng, Mingkai and Dong, Minjing and You, Shan and Xu, Chang},
  journal={arXiv preprint arXiv:2210.14670},
  year={2022}
}

More interesting works based on Probabilistic Representations are coming soon. 👣

Contact

If you have any questions or meet any problems, please feel free to contact us.

• Haoyu Xie, 895852154@qq.com
• Changqi Wang, wangchangqi98@gmail.com