The online bi-modal place recognition methods used in this software are described in the following paper (available here). If you use this work in an academic context, please cite the following publication(s):

@inproceedings{pan2021coral,
  title={Coral: Colored structural representation for bi-modal place recognition},
  author={Pan, Yiyuan and Xu, Xuecheng and Li, Weijie and Cui, Yunxiang and Wang, Yue and Xiong, Rong},
  booktitle={2021 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  pages={2084--2091},
  year={2021},
  organization={IEEE}
}

ele_stream_train.py and img_stream_train.py are single-mode training scripts for elevation map and front view image;
multi_stream_train.py is a multi-mode training script;
Please refer to the GEM to get the data of elevation map.