Design considerations for a computer-vision-enabled ophthalmic augmented reality environment

We have initiated studies towards the design and implementation of an ophthalmic augmented reality environment in order to allow for a) more precise laser treatment for ophthalmic diseases, b) teaching, c) telemedicine, and d) real-time image measurement, analysis, and comparison. The proposed system is being designed around a standard slit-lamp biomicroscope. The microscope will be interfaced to a CCD camera, and the image sent to a video capture board. A single computer workstation will coordinate image capture , registration, and display. The captured image is registered with previously stored, montaged photographic and angiographic data, with superposition facilitated by fundus-landmark-based fast registration algorithms. The computer then drives a high intensity, VGA resolution video display with adjustable brightness and contrast attached to one of the oculars of the slitlamp biomicroscope. Preliminary studies with a modiied binocular operating microscope interfaced to a Sun Ultra1 Workstation and an IBM-compatible PC demonstrates proof-of-principle. Robust, accurate fundus image montaging is accomplished with Hausdorr-distance-based methods. For photographic and angiographic data where the vessel gray levels vary from light to dark, and intensity-based correlation methods fail, image-preprocessing with smoothing, edge-detection, and thresholding facilitates registration. Non-real-time registration (0:4 ? 4:0 CPU seconds) is achieved by non-optimized simple template matching (translation only, Matrox Inspector) or Hausdorr-distance-based (translation and scaling) algorithms performed on edge-detected fundus photographic and angiographic images, and on images of a model eye. Successful registration and image overlay of color, monochromatic, and angiographic images is demonstrated. To our knowledge , these studies represent the rst investigation towards design and implementation of an ophthalmic augmented reality environment. Summary Page a. What is the original contribution of this work? To our knowledge, our investigations represent the rst investigations towards the design and construction of an ophthalmic augmented reality environment b. Why should this contribution be considered important? Our application should allow for more eecacious treatment and evaluation of potentially blinding diseases. c. What is the most closely related work by others and how does this work diier? Similar investigations of image overlay/augmented reality in other surgical disciplines have be explored, but these technologies and methods have not been applied to diagnosis and treatment of eye diseases. d. How can other researchers make use of the results of this work? Our results demonstrate new methods for fast, two dimensional image registration, and we present a novel design for an image overlay applications. e. If this work extends or relates closely to …