title: An Automatic Algorithm for Segmentation of the Boundaries of Corneal Layers in Optical Coherence Tomography Images using Gaussian Mixture Model.
abstract: Diagnosis of corneal diseases is possible by measuring and evaluation of corneal thickness in different layers. Thus, the need for precise segmentation of corneal layer boundaries is inevitable. Obviously, manual segmentation is time-consuming and imprecise. In this paper, the Gaussian mixture model (GMM) is used for automatic segmentation of three clinically important corneal boundaries on optical coherence tomography (OCT) images. For this purpose, we apply the GMM method in two consequent steps. In the first step, the GMM is applied on the original image to localize the first and the last boundaries. In the next step, gradient response of a contrast enhanced version of the image is fed into another GMM algorithm to obtain a more clear result around the second boundary. Finally, the first boundary is traced toward down to localize the exact location of the second boundary. We tested the performance of the algorithm on images taken from a Heidelberg OCT imaging system. To evaluate our approach, the automatic boundary results are compared with the boundaries that have been segmented manually by two corneal specialists. The quantitative results show that the proposed method segments the desired boundaries with a great accuracy. Unsigned mean errors between the results of the proposed method and the manual segmentation are 0.332, 0.421, and 0.795 for detection of epithelium, Bowman, and endothelium boundaries, respectively. Unsigned mean errors of the inter-observer between two corneal specialists have also a comparable unsigned value of 0.330, 0.398, and 0.534, respectively.
authors.affiliation: Department of Advanced Medical Technologies, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mahdi Kazemian
authors.initials: MK
authors.lastname: Jahromi
authors.affiliation: Department of Advanced Medical Technologies, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Raheleh
authors.initials: R
authors.lastname: Kafieh
authors.affiliation: Department of Advanced Medical Technologies, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Rabbani
authors.affiliation: Department of Advanced Medical Technologies, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Alireza Mehri
authors.initials: AM
authors.lastname: Dehnavi
authors.affiliation: Department of Ophthalmology, Isfahan University of Medical Sciences and Health Services, Isfahan, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Peyman
authors.affiliation: Noor Ophthalmology Research Center, Noor Eye Hospital, Tehran, Iran.
authors.forename: Fedra
authors.initials: F
authors.lastname: Hajizadeh
authors.affiliation: Department of Advanced Medical Technologies, Medical Image and Signal Processing Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Ommani
keywords: Corneal layers; Gaussian mixture model; optical coherence tomography; segmentation