@article{cerf2007ocr,
  title={{Observers are consistent when rating image conspicuity}},
  author={Cerf, M. and Cleary, D.R. and Peters, R.J. and Einh{\"a}user, W. and Koch, C.},
  journal={Vision Research},
  volume={47},
  number={24},
  pages={3052--3060},
  year={2007},
  publisher={Elsevier}
}