@article{chirarattananon2018direct,
  title={A direct optic flow-based strategy for inverse flight altitude estimation with monocular vision and IMU measurements},
  author={Chirarattananon, Pakpong},
  journal={Bioinspiration \& biomimetics},
  volume={13},
  number={3},
  pages={036004},
  year={2018},
  publisher={IOP Publishing}
}