@article{wu_hong_rosenfeld_1982, 
  title={Threshold Selection Using Quadtrees}, 
  volume={PAMI-4}, 
  DOI={10.1109/tpami.1982.4767203}, 
  publisher={Institute of Electrical and Electronics Engineers (IEEE)}, 
  author={Wu and Hong and Rosenfeld}, 
  year={1982}
  }