  Blueworks - Medical Expert Diagnosis is developing an application, BWEye, to
be used as an ophthalmology consultation decision support system. The
implementation of this application involves several different tasks and one of
them is the implementation of an ophthalmology images registration algorithm.
The work reported in this document is related with the implementation of an
algorithm to register images of angiography, colour retinography and redfree
retinography. The implementations described were developed in the software
MATLAB.
  The implemented algorithm is based in the detection of the bifurcation points
(y-features) of the vascular structures of the retina that usually are visible
in the referred type of images. There are proposed two approaches to establish
an initial set of features correspondences. The first approach is based in the
maximization of the mutual information of the bifurcation regions of the
features of images. The second approach is based in the characterization of
each bifurcation point and in the minimization of the Euclidean distance
between the descriptions of the features of the images in the descriptors
space. The final set of the matching features for a pair of images is defined
through the application of the RANSAC algorithm.
  Although, it was not achieved the implementation of a full functional
algorithm, there were made several analysis that can be important to future
improvement of the current implementation.
