Registration of Retinal Angiograms Using Self Organizing Maps

Abstract

In this paper, an automatic method for registering multimodal retinal images is presented. The method consists of three steps: the vessel centerline detection and extraction of bifurcation points only in the reference image, the automatic correspondence of bifurcation points in the two images using a novel implementation of the Self Organized Maps (SOMs) and the extraction of the parameters of the affine transform using the previously obtained correspondences. The proposed registration algorithm was tested on 24 multimodal retinal pairs and the obtained results show an advantageous performance in terms of accuracy with respect to the manual registration.

Deformable registration of retinal fluorescein angiogram sequences using vasculature structures

“…However these algorithms do not perform as well with FA sequences because they are designed to deal with changes of content appearance (e.g., due to different sensors imaging the same organs) but not with content changes, which occur throughout a FA sequence as different portions or the vascular structure are visible (perfused) in different frames, see Figure 1. A few registration algorithms for FA sequence have been reported, both estimating a single, global transformation, [6], [7] and performing deformable registration [8], [9]. All of them have been applied to sequences with fields of view typical of standard fundus cameras (around 45 degrees), which do not contain many of the challenges of UWFV FA: ciliar occlusions, peripheral blurring, irregular time intervals between frame acquisitions, fewer vessels in periphery to mention some.…”