@article{li2021hard,
  title={A Hard Example Mining Approach for Concealed Multi-Object Detection of Active Terahertz Image},
  author={Li, Ling and Xue, Fei and Liang, Dong and Chen, Xiaofei},
  journal={Applied Sciences},
  volume={11},
  number={23},
  pages={11241},
  year={2021},
  publisher={Multidisciplinary Digital Publishing Institute}
}