@article{article98dba9ee,
title   = {Spatial and frequency domain techniques for segmentation of placido images and accuracy implications for videokeratography},
author = {Carvalho, Luís Alberto Vieira de and Bruno, Odemir Martinez},
year = {2005},
doi = {10.1016/j.cmpb.2005.01.006},
journal   = {Computer Methods and Programs in Biomedicine}
}