Methodology for the registration of whole SLO sequences

Images acquired with the Scanning Laser Ophthalmoscope (SLO) device offer a very good tool for the evaluation of retinal diseases and obtaining interesting haemodynamic variables related to retinal blood flow. But because of the unavoidable eye movements, it is necessary a previous registration process to obtain a reliable analysis of the information extracted from these set of frames. This paper explains an algorithm which allows a fully automatic registration of the whole SLO sequence by combining two registration techniques: a landmark based registration and a mutual information based one. The accurate registration of the frames will allow the automatic calculation of the so called dye dilution curves, which are computed by means of a robust fitting algorithm based on the optimisation method Simulated Annealing. With that curves it will be possible to obtain valuable haemodynamic variables, like the arteriovenous passage time described here.