CenterFusion

This repository contains the implementation of CenterFusion: Center-based Radar and Camera Fusion for 3D Object Detection.

Citing CenterFusion

If you find CenterFusion useful in your research, please consider citing:

CenterFusion: Center-based Radar and Camera Fusion for 3D Object Detection
Ramin Nabati, Hairong Qi

@article{nabati2020centerfusion,
  title={CenterFusion: Center-based Radar and Camera Fusion for 3D Object Detection},
  author={Nabati, Ramin and Qi, Hairong},
  journal={arXiv preprint arXiv:2011.04841},
  year={2020}
}

---

Contents

• Introduction
• Results
• Installation
• Dataset Preparation
• Pretrained Models
• Training
• Testing
• References
• License

Introduction

We focus on the problem of radar and camera sensor fusion and propose a middle-fusion approach to exploit both radar and camera data for 3D object detection. Our method, called CenterFusion, first uses a center point detection network to detect objects by identifying their center points on the image. It then solves the key data association problem using a novel frustum-based method to associate the radar detections to their corresponding object's center point. The associated radar detections are used to generate radar-based feature maps to complement the image features, and regress to object properties such as depth, rotation and velocity. We evaluate CenterFusion on the challenging nuScenes dataset, where it improves the overall nuScenes Detection Score (NDS) of the state-of-the-art camera-based algorithm by more than 12%. We further show that CenterFusion significantly improves the velocity estimation accuracy without using any additional temporal information.

Results

• Overall results:

  Dataset	NDS	mAP	mATE	mASE	mAOE	mAVE	mAAE
  nuScenes Test	0.449	0.326	0.631	0.261	0.516	0.614	0.115
  nuScenes Val	0.453	0.332	0.649	0.263	0.535	0.540	0.142

• Per-class mAP:

  Dataset	Car	Truck	Bus	Trailer	Const.	Pedest.	Motor.	Bicycle	Traff.	Barrier
  nuScenes Test	0.509	0.258	0.234	0.235	0.077	0.370	0.314	0.201	0.575	0.484
  nuScenes Val	0.524	0.265	0.362	0.154	0.055	0.389	0.305	0.229	0.563	0.470

• Qualitative results:

Installation

The code has been tested on Ubuntu 16.04 and CentOS 7 with Python 3.7, CUDA 10.0 and PyTorch 1.2. For installation, follow these steps:

1. Create a new virtual environment (optional):

   mkvirtualenv centerfusion  

2. Install PyTorch:

   pip install torch torchvision

3. Install COCOAPI:

   pip install cython; pip install -U 'git+https://github.com/cocodataset/cocoapi.git#subdirectory=PythonAPI'

4. Clone the CenterFusion repository with the --recursive option. We'll call the directory that you cloned CenterFusion into CF_ROOT:

   CF_ROOT=/path/to/CenterFusion
   git clone --recursive https://github.com/mrnabati/CenterFusion.git $CF_ROOT

5. Install the requirements:

   cd $CF_ROOT
   pip install -r requirements.txt

6. Build the deformable convolution library:

   cd $CF_ROOT/src/lib/model/networks/DCNv2
   ./make.sh

   Note: If the DCNv2 folder does not exist in the networks directory, it can be downloaded using this command:

   cd $CF_ROOT/src/lib/model/networks
   git clone https://github.com/CharlesShang/DCNv2/

Dataset Preparation

1. Download the nuScenes dataset from nuScenes website.

2. Extract the downloaded files in the ${CF_ROOT}\data\nuscenes directory. You should have the following directory structure after extraction:

   ${CF_ROOT}
   `-- data
       `-- nuscenes
           |-- maps
           |-- samples
           |   |-- CAM_BACK
           |   |   | -- xxx.jpg
           |   |   ` -- ...
           |   |-- CAM_BACK_LEFT
           |   |-- CAM_BACK_RIGHT
           |   |-- CAM_FRONT
           |   |-- CAM_FRONT_LEFT
           |   |-- CAM_FRONT_RIGHT
           |   |-- RADAR_BACK_LEFT
           |   |   | -- xxx.pcd
           |   |   ` -- ...
           |   |-- RADAR_BACK_RIGHT
           |   |-- RADAR_FRON
           |   |-- RADAR_FRONT_LEFT
           |   `-- RADAR_FRONT_RIGHT
           |-- sweeps
           |-- v1.0-mini
           |-- v1.0-test
           `-- v1.0-trainval
   

3. Run the convert_nuScenes.py script to convet the nuScenes dataset to COCO format:

   cd $CF_ROOT/src/tools
   python convert_nuScenes.py

Pretrained Models

The pre-trained CenterFusion model and the baseline CenterNet model can be downloaded from the links below:

model	epochs	GPUs	Backbone	Val NDS	Val mAP	Test NDS	Test mAP
centerfusion_e60	60	2x Nvidia Quadro P5000	DLA	0.453	0.332	0.449	0.326
centernet_baseline_e170	170	2x Nvidia Quadro P5000	DLA	0.328	0.306	-	-
Notes:

• The centernet_baseline_e170 model is obtained by starting from the original CenterNet 3D detection model (nuScenes_3Ddetection_e140) and training the velocity and attributes heads for 30 epochs.

Training

The $CF_ROOT/experiments/train.sh script can be used to train the network:

cd $CF_ROOT
bash experiments/train.sh

The --train_split parameter determines the training set, which could be mini_train or train. the --load_model parameter can be set to continue training from a pretrained model, or removed to start training from scratch. You can modify the parameters in the script as needed, or add more supported parameters from $CF_ROOT/src/lib/opts.py.

Testing

Download the pre-trained model into the $CF_ROOT/models directory and use the $CF_ROOT/experiments/test.sh script to run the evaluation:

cd $CF_ROOT
bash experiments/test.sh

Make sure the --load_model parameter in the script provides the path to the downloaded pre-trained model. The --val_split parameter determines the validation set, which could be mini_val, val or test. You can adjust the other parameters as needed, or add more supported parameters from $CF_ROOT/src/lib/opts.py.

---

References

The following works have been used by CenterFusion:

@inproceedings{zhou2019objects,
title={Objects as Points},
author={Zhou, Xingyi and Wang, Dequan and Kr{\"a}henb{\"u}hl, Philipp},
booktitle={arXiv preprint arXiv:1904.07850},
year={2019}
}

@article{zhou2020tracking,
title={Tracking Objects as Points},
author={Zhou, Xingyi and Koltun, Vladlen and Kr{\"a}henb{\"u}hl, Philipp},
journal={ECCV},
year={2020}
}

@inproceedings{nuscenes2019,
title={{nuScenes}: A multimodal dataset for autonomous driving},
author={Holger Caesar and Varun Bankiti and Alex H. Lang and Sourabh Vora and Venice Erin Liong and Qiang Xu and Anush Krishnan and Yu Pan and Giancarlo Baldan and Oscar Beijbom},
booktitle={CVPR},
year={2020}
}

License

CenterFusion is based on CenterNet and is released under the MIT License. See NOTICE for license information on other libraries used in this project.