Automatic registration of spectrophotometric retinal images

This study is a part of the development of a system that enables analysis of spectrophotometric measurements of oxygen saturation in the retinal vasculature. A digital fundus camera is used to capture four spectral images using an image splitter with 542 nm, 558 nm, 586 nm and 605 nm band-pass filters. Before the spectral images can be used to analyze the optical density ratios they have to go through a preprocessing stage where they are registered together in software. The registration process is different from previous registration algorithms because the images are at very low resolution and therefore we propose a more data oriented method. To validate the registration we propose a method which uses the distance between edges in images. This method could be valuable to quantify the registration accuracy in more general image registration problems.