Comparison of quasi-spherical surfaces : application to corneal biometry
Article [Version publiée]
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IET biometrics ; vol. 5, no 3, p. 212-219.Éditeur·s
Institution of Engineering and TechnologyRésumé·s
In this study, the authors present two new techniques with their own particular advantages dedicated to the
authentication of a person based on the three-dimensional geometry of the cornea. A device known as corneal
topographer is used for capturing the shape of each cornea. Until now only a few studies on corneal biometry have
been conducted and they were limited only to the anterior surface. In this study, since the whole cornea is a tissue
layered by two (anterior and posterior) surfaces, the authors propose to use both surfaces to characterise the corneal
shape. The first proposed method consists of comparing coefficients from a spherical harmonics decomposition, and
this allows to do a fast comparison that can be used to perform many-to-one comparisons. The second approach is
based on the minimal residual volume between two corneas after a registration step, this geometry-based method is
more accurate but slower, and is thus used to perform one-to-one comparisons. A cascade fusion scheme is also
proposed to benefit from the advantages of both methods. The authors’ study demonstrates that corneal shape could
be used for biometry. The two proposed methods have been tested and validated on a dataset of 257 corneas.