DPCL (AAAI 2023 Oral): Official Project Webpage

This repository provides the official PyTorch implementation of the following paper:

Generalized Semantic Segmentation by Self-Supervised Source Domain Projection and Multi-Level Contrastive Learning
Liwei Yang* (Xi’an Jiaotong University), XiangGu* (Xi’an Jiaotong University), JianSun (Xi’an Jiaotong University, Pazhou Laboratory (Huangpu) and Peng Cheng Laboratory.) (*: equal contribution)
AAAI 2023, Accepted as Oral Presentation

Abstract: Deep networks trained on the source domain show degraded performance when tested on unseen target domain data. To enhance the model's generalization ability, most existing domain generalization methods learn domain invariant features by suppressing domain sensitive features. Different from them, we propose a Domain Projection and Contrastive Learning (DPCL) approach for generalized semantic segmentation, which includes two modules: Self-supervised Source Domain Projection (SSDP) and Multi-level Contrastive Learning (MLCL). SSDP aims to reduce domain gap by projecting data to the source domain, while MLCL is a learning scheme to learn discriminative and generalizable features on the projected data. During test time, we first project the target data by SSDP to mitigate domain shift, then generate the segmentation results by the learned segmentation network based on MLCL. At test time, we can update the projected data by minimizing our proposed pixel-to-pixel contrastive loss to obtain better results. Extensive experiments for semantic segmentation demonstrate the favorable generalization capability of our method on benchmark datasets.

DPCL - Pytorch

Implementation of DPCL, domain generalized network for segmentation, in Pytorch. The full paper can be found in this.

How to Run DPCL

We evaludated DPCL on Cityscapes, BDD-100K,Synthia (SYNTHIA-RAND-CITYSCAPES), GTAV and Mapillary Vistas.

We adopt Class uniform sampling proposed in this paper to handle class imbalance problems. GTAVUniform and CityscapesUniform are the datasets to which Class Uniform Sampling is applied.

1. For Cityscapes dataset, download "leftImg8bit_trainvaltest.zip" and "gtFine_trainvaltest.zip" from https://www.cityscapes-dataset.com/downloads/
   Unzip the files and make the directory structures as follows.

cityscapes
 └ leftImg8bit_trainvaltest
   └ leftImg8bit
     └ train
     └ val
     └ test
 └ gtFine_trainvaltest
   └ gtFine
     └ train
     └ val
     └ test

bdd-100k
 └ images
   └ train
   └ val
   └ test
 └ labels
   └ train
   └ val

mapillary
 └ training
   └ images
   └ labels
 └ validation
   └ images
   └ labels
 └ test
   └ images
   └ labels

We used GTAV_Split to split GTAV dataset into training/validation/test set. Please refer the txt files in in the code of RobustNet split_data.

GTAV
 └ images
   └ train
     └ folder
   └ valid
     └ folder
   └ test   
     └ folder
 └ labels
   └ train
     └ folder
   └ valid
     └ folder
   └ test   
     └ folder

We randomly splitted Synthia dataset into train/val set. Please refer the txt files in the code of RobustNet split_data.

synthia
 └ RGB
   └ train
   └ val
 └ GT
   └ COLOR
     └ train
     └ val
   └ LABELS
     └ train
     └ val

2. You should modify the path in "<path_to_dpcl>/segmentation_network/config.py" according to your dataset path.

#Cityscapes Dir Location
__C.DATASET.CITYSCAPES_DIR = <YOUR_CITYSCAPES_PATH>
#Mapillary Dataset Dir Location
__C.DATASET.MAPILLARY_DIR = <YOUR_MAPILLARY_PATH>
#GTAV Dataset Dir Location
__C.DATASET.GTAV_DIR = <YOUR_GTAV_PATH>
#BDD-100K Dataset Dir Location
__C.DATASET.BDD_DIR = <YOUR_BDD_PATH>
#Synthia Dataset Dir Location
__C.DATASET.SYNTHIA_DIR = <YOUR_SYNTHIA_PATH>

3. You can train DPCL with following commands.

Step 1 Pre-train the source projection network.

<path_to_dpcl>/pretrain_ae/$ python pretrain_autoencoder.py

Step 2 Fixed the source projection network. Train the segmentation network. (For example, trained on the GTAV.)

<path_to_dpcl>/segmentation_network/$ source ./scripts/train_r50_gtav_dpcl.sh # Train: GTAV, Test: BDD100K, Cityscapes, Mapillary / ResNet50, DPCL

Step 3 Test time process. (This test process is the way evaluated in our paper. The test process in the train file is a faster way without alter mean and var in the test process.)

#Load the snapshot
--snapshot = <YOUR_SNAPSHOT_PATH>
#Load the mean var center in the following files
center under the <path_to_dpcl>/class_center
<path_to_dpcl>/segmentation_network/$ python test_alter_mean_var.py # DPCL. DPCL wo TTA.
<path_to_dpcl>/segmentation_network/$ python test_iter_contrast.py # DPCL+TTA (C). Only iterate pixel-to-pixel contrastive loss in the test time.
<path_to_dpcl>/segmentation_network/$ python test_iter_contrast_entropy.py # DPCL+TTA (C+E). Iterate pixel-to-pixel contrastive and entropy loss in the test time.

Pretrained Models

You can download the pretrained source projection network evaluated in our paper at Google Drive. Please put the pretrained source projection model in the folder <path_to_dpcl>/pretrain_ae/

If you use DPCL in your research or wish to refer to the baseline results published in our paper, please use the following BibTeX entry.

@inproceedings{DPCL,
  title={Generalized Semantic Segmentation by Self-Supervised Source Domain Projection and Multi-Level Contrastive Learning},
  author={Liwei Yang, XiangGu, and JianSun},
  journal={AAAI},
  year={2023}
}

Questions for code

If you meet any questions of our code or paper. Please send email to yangliwei@stu.xjtu.edu.cn at any time.

Acknowledgement

Code is largely based on RobustNet. We use the same way of data splitting with RobustNet. More details can be seen in RobustNet.