title: Augmented reality fundus biomicroscopy: a working clinical prototype.
abstract: BACKGROUND
  To guide treatment for macular diseases and to facilitate real-time image correlation, measurement, and comparison, we developed a method for direct overlay of previously stored photographic and angiographic images onto the real-time slitlamp fundus view.
  
  
  METHODS
  Previously acquired fundus photographs and angiography images were digitized. A slitlamp interfaced to a charge-coupled device camera, framegrabber, and computer allowed for real-time acquisition and digitization of slitlamp fundus images that was synchronous with posterior segment examination. Custom-developed video injectors containing a miniature cathode ray tube display allowed for real-time superposition of angiographic images to the fundus view. Registration and tracking algorithms were developed and deployed in C++. The feasibility of this approach was demonstrated in 5 human subjects.
  
  
  RESULTS
  The computer-vision algorithms provided robust registration, tracking, and image overlay of previously stored photographic and angiographic images directly onto the real-time fundus view. Accurate tracking was demonstrated with updates at 3 to 5 Hz. Direct overlay of previously stored images confirmed registration accuracy, but examiners preferred a more simple rendering that included only relevant information and eliminated extraneous, potentially confusing image data.
  
  
  CONCLUSIONS
  Slitlamp-based video injection of previously stored images allows for accurate, robust, real-time correlation and comparison to the biomicroscopic fundus view in human subjects.
authors.affiliation: Computer Vision Laboratory, Scheie Eye Institute, University of Pennsylvania, 51 N 39th St, Philadelphia, PA 19104, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Berger
authors.forename: B
authors.initials: B
authors.lastname: Madjarov
mesh_terms: D000465:Algorithms; D003199:Computer Systems; D005240:Feasibility Studies; D005451:Fluorescein Angiography / Q000295:instrumentation*; D005654:Fundus Oculi; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation* / Q000379:methods; D010781:Photography / Q000295:instrumentation*