Motion estimation of ocular fundus images

Unstable fixation due to involuntary eye movements, poor visual acuity or oculomotor disorder is one of the biggest difficulties in applying noninvasive diagnostic techniques to the human eye in a clinical setting. To address this limitation, the authors have implemented a motion estimation algorithm applicable to fundus image sequences which is based on an affine model of eye movement. A hierarchical coding scheme accommodating various spatial resolutions was used in view of minimizing the processing time and adapting the algorithm to various types of eye movements that may be encountered in patients suffering from different eye diseases. The results suggest that the technique can successfully monitor patient fixation and could be used to disable other measurements or procedures during those time intervals when fixation is not maintained within predetermined limits