Few-shot 3D Point Cloud Semantic Segmentation

Created by Na Zhao from National University of Singapore

Introduction

This repository contains the PyTorch implementation for our CVPR 2021 Paper "Few-shot 3D Point Cloud Semantic Segmentation" by Na Zhao, Tat-Seng Chua, Gim Hee Lee.

Many existing approaches for point cloud semantic segmentation are fully supervised. These fully supervised approaches heavily rely on a large amount of labeled training data that is difficult to obtain and can not generalize to unseen classes after training. To mitigate these limitations, we propose a novel attention-aware multi-prototype transductive few-shot point cloud semantic segmentation method to segment new classes given a few labeled examples. Specifically, each class is represented by multiple prototypes to model the complex data distribution of 3D point clouds. Subsequently, we employ a transductive label propagation method to exploit the affinities between labeled multi-prototypes and unlabeled query points, and among the unlabeled query points. Furthermore, we design an attention-aware multi-level feature learning network to learn the discriminative features that capture the semantic correlations and geometric dependencies between points. Our proposed method shows significant and consistent improvements compared to the baselines in different few-shot point cloud segmentation settings (i.e. 2/3-way 1/5-shot) on two benchmark datasets.

Installation

• Install python --This repo is tested with python 3.6.8.
• Install pytorch with CUDA -- This repo is tested with torch 1.4.0, CUDA 10.1. It may work with newer versions, but that is not gauranteed.
• Install faiss with cpu version
• Install 'torch-cluster' with the corrreponding torch and cuda version

  pip install torch-cluster==latest+cu101 -f https://pytorch-geometric.com/whl/torch-1.5.0.html

• Install dependencies

  pip install tensorboard h5py transforms3d

Usage

Data preparation

S3DIS

1. Download S3DIS Dataset Version 1.2.
2. Re-organize raw data into npy files by running

   cd ./preprocess
   python collect_s3dis_data.py --data_path $path_to_S3DIS_raw_data

   The generated numpy files are stored in ./datasets/S3DIS/scenes/data by default.

3. To split rooms into blocks, run

   python ./preprocess/room2blocks.py --data_path ./datasets/S3DIS/scenes/

   One folder named blocks_bs1_s1 will be generated under ./datasets/S3DIS/ by default.

ScanNet

1. Download ScanNet V2.
2. Re-organize raw data into npy files by running

   cd ./preprocess
   python collect_scannet_data.py --data_path $path_to_ScanNet_raw_data

   The generated numpy files are stored in ./datasets/ScanNet/scenes/data by default.

3. To split rooms into blocks, run

   python ./preprocess/room2blocks.py --data_path ./datasets/ScanNet/scenes/ --dataset scannet

   One folder named blocks_bs1_s1 will be generated under ./datasets/ScanNet/ by default.

Running

Training

First, pretrain the segmentor which includes feature extractor module on the available training set:

cd scripts
bash pretrain_segmentor.sh

Second, train our method:

bash train_attMPTI.sh

Evaluation

bash eval_attMPTI.sh

Note that the above scripts are used for 2-way 1-shot on S3DIS (S^0). You can modified the corresponding hyperparameters to conduct experiments on other settings.

Citation

Please cite our paper if it is helpful to your research:

@inproceedings{zhao2021few,
  title={Few-shot 3D Point Cloud Semantic Segmentation},
  author={Zhao, Na and Chua, Tat-Seng and Lee, Gim Hee},
  booktitle={Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition},
  year={2021}
}

Acknowledgement

We thank DGCNN (pytorch) for sharing their source code.