title: Markerless monocular tracking system for guided external eye surgery.
abstract: This paper presents a novel markerless monocular tracking system aimed at guiding ophthalmologists during external eye surgery. This new tracking system performs a very accurate tracking of the eye by detecting invariant points using only textures that are present in the sclera, i.e., without using traditional features like the pupil and/or cornea reflections, which remain partially or totally occluded in most surgeries. Two known algorithms that compute invariant points and correspondences between pairs of images were implemented in our system: Scalable Invariant Feature Transforms (SIFT) and Speed Up Robust Features (SURF). The results of experiments performed on phantom eyes show that, with either algorithm, the developed system tracks a sphere at a 360° rotation angle with an error that is lower than 0.5%. Some experiments have also been carried out on images of real eyes showing promising behavior of the system in the presence of blood or surgical instruments during real eye surgery.
authors.affiliation: LabHuman, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain. Electronic address: cmonserrat@labhuman.i3bh.es.
authors.forename: C
authors.initials: C
authors.lastname: Monserrat
authors.affiliation: LabHuman, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rupérez
authors.affiliation: LabHuman, Universitat Politècnica de València, Camino de Vera s/n, 46022 Valencia, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Alcañiz
authors.affiliation: Fisabio Oftalmológica Médica, Bifurcación Pío Baroja-General Avilés, s/n, 46015 Valencia, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Mataix
mesh_terms: D005133:Eye Movements / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D013508:Ophthalmologic Surgical Procedures / Q000295:instrumentation / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D019047:Phantoms, Imaging; D010781:Photography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D014741:Video Recording / Q000379:methods*
keywords: Computer aided surgery; External eye surgery; Eye tracking; Markerless video tracking; SIFT; SURF