@article{Minhas2012An,
  title={An Efficient Algorithm for Focus Measure Computation in Constant Time},
  author={Minhas, Rashid and Mohammed, Abdul Adeel and Wu, Q. M. Jonathan},
  journal={IEEE Transactions on Circuits & Systems for Video Technology},
  volume={22},
  number={1},
  pages={152-156},
  year={2012},
}