title: Automatic estimation of the corneal limbus in videokeratoscopy.
abstract: An algorithm for estimating the corneal limbus from videokeratoscopic images is proposed. After the image is transformed to a polar grid, a novel edge-detection procedure, suitable for the detection of the soft edge produced by the limbus, is used to locate the limbus. Outliers due to the eyelids, eyelashes, and videokeratoscopic rings are removed by taking advantage of the approximate circularity of the cornea. An ellipse which minimizes the sum of the squared algebraic errors is fitted to the remaining edge points. Comparisons between the proposed algorithm, a manual computer-based technique and an algorithm which uses conventional edge-detection techniques demonstrate the accuracy of the proposed algorithm.
authors.affiliation: Centre for Eye Research, Queensland University of Technology, Kelvin Grove Q4059, Australia.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Morelande
authors.forename: D Robert
authors.initials: DR
authors.lastname: Iskander
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Collins
authors.forename: Ross
authors.initials: R
authors.lastname: Franklin
mesh_terms: D000465:Algorithms; D001251:Astigmatism / Q000175:diagnosis; D003198:Computer Simulation; D019781:Corneal Topography / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007640:Keratoconus / Q000175:diagnosis; D016850:Limbus Corneae / Q000033:anatomy & histology*; D010363:Pattern Recognition, Automated; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014741:Video Recording / Q000379:methods*