Enhancing the signal-to-noise ratio in ophthalmic optical coherence tomography by image registration—method and clinical examples

Thomas Martini Jo̸rgensen, Jakob Thomadsen, Ulrik Christensen, Wael Soliman, Birgit Sander
2007 Journal of Biomedical Optics  
Optical coherence tomography ͑OCT͒ has already proven an important clinical tool for imaging and diagnosing retinal diseases. Concerning the standard commercial ophthalmic OCT systems, speckle noise is a limiting factor with respect to resolving relevant retinal features. We demonstrate successful suppression of speckle noise from mutually aligning a series of in vivo OCT recordings obtained from the same retinal target using the Stratus system from Humphrey-Zeiss. Our registration technique is
more » ... able to account for the axial movements experienced during recording as well as small transverse movements of the scan line from one scan to the next. The algorithm is based on a regularized shortest path formulation for a directed graph on a map formed by interimage ͑B-scan͒ correlations. The resulting image enhancement typically increases the contrast-tonoise ratio ͑CNR͒ with a factor of three or more and facilitates segmentation and quantitative characterization of pathologies. The method is currently successfully being applied by medical doctors in a number of specific retinal case studies. © 2007 Society of Photo-Optical Instrumentation Engineers.
doi:10.1117/1.2772879 pmid:17867797 fatcat:vgeya6yzojflpk7wroif2ig3wq