Locus

This repository is an open-source implementation of the ICRA 2021 paper: Locus: LiDAR-based Place Recognition using Spatiotemporal Higher-Order Pooling.

More information: https://research.csiro.au/robotics/locus-pr/

Paper Pre-print: https://arxiv.org/abs/2011.14497

Method overview.

Locus is a global descriptor for large-scale place recognition using sequential 3D LiDAR point clouds. It encodes topological relationships and temporal consistency of scene components to obtain a discriminative and view-point invariant scene representation.

Usage

Set up environment

This project has been tested on Ubuntu 18.04 (with Open3D 0.11, tensorflow 1.8.0, pcl 1.8.1 and python-pcl 0.3.0). Set up the requirments as follows:

• Create conda environment with open3d and tensorflow-1.8 with python 3.6:

conda create --name locus_env python=3.6
conda activate locus_env
pip install -r requirements.txt

• Set up python-pcl. See utils/setup_python_pcl.txt. For further instructions, see here.
• Segment feature extraction uses the pre-trained model from ethz-asl/segmap. Download and copy the relevant content in segmap_data into ~/.segmap/:

./utils/get_segmap_data.bash

• Download the KITTI odometry dataset and set the path in config.yml.

Descriptor Generation

Segment and generate Locus descriptor for each scan in a selected sequence (e.g., KITTI sequence 06):

python main.py --seq '06'

The following flags can be used with main.py:

• --seq: KITTI dataset sequence number.
• --aug_type: Scan augmentation type (optional for robustness tests).
• --aug_param: Parameter corresponding to above augmentation.

Evaluation

Sequence-wise place-recognition using extracted descriptors:

python ./evaluation/place_recognition.py  --seq  '06' 

Evaluation of place-recognition performance using Precision-Recall curves (multiple sequences):

python ./evaluation/pr_curve.py 

Additional scripts

Robustness tests:

Code of the robustness tests carried out in section V.C in paper. Extract Locus descriptors from scans of select augmentation:

python main.py --seq '06' --aug_type 'rot' --aug_param 180 # Rotate about z-axis by random angle between 0-180 degrees. 
python main.py --seq '06' --aug_type 'occ' --aug_param 90 # Occlude sector of 90 degrees about random heading. 

Evaluation is done as before. For vizualization, set config.yml->segmentation->visualize to True.

Testing individual modules:

python ./segmentation/extract_segments.py # Extract and save Euclidean segments (S).
python ./segmentation/extract_segment_features.py # Extract and save SegMap-CNN features (Fa) for given S.
python ./descriptor_generation/spatial_pooling.py # Generate and save spatial segment features for given S and Fa.
python ./descriptor_generation/temporal_pooling.py # Generate and save temporal segment features for given S and Fa.
python ./descriptor_generation/locus_descriptor.py # Generate and save Locus global descriptor using above.

Citation

If you find this work usefull in your research, please consider citing:

@inproceedings{vid2021locus,
  title={Locus: LiDAR-based Place Recognition using Spatiotemporal Higher-Order Pooling},
  author={Vidanapathirana, Kavisha and Moghadam, Peyman and Harwood, Ben and Zhao, Muming and Sridharan, Sridha and Fookes, Clinton},
  booktitle={IEEE International Conference on Robotics and Automation (ICRA)},
  year={2021},
  eprint={arXiv preprint arXiv:2011.14497}
}

Acknowledgment

Functions from 3rd party have been acknowledged at the respective function definitions or readme files. This project was mainly inspired by the following: ethz-asl/segmap and irapkaist/scancontext.

Contact

For questions/feedback,

[email protected]