Motion Detection and Compensation of Affine Deformations in Infrared Retinal Videos

Abstract

Diabetic macular edema (DME) affects the retina and reduces the visual acuity of patients with severe diabetic retinopathy. Its conventional treatment involves laser photocoagulation combined with infrared (IR) imaging. However, the laser beam may hit healthy retinal areas and cause unintentional retinal damages if retinal motion occurs. We propose a method for retinal motion detection and compensation that relies on phase correlations in the image and in the log-polar domains, and is robust to affine retinal deformations (e.g., rotations, scales, and translations) in IR videos. The proposed method is also robust to the background noise and illumination changes commonly occurring in this retinal imaging modality. The proposed method can be used to estimate the retinal affine motion parameters and compensate for small retinal motions (nearly 50 $\mu \text{m}$ ). The critical method parameters are selected and adjusted optimally, which improves the robustness of the method. The experimental results suggest that the proposed method potentially can be more robust for detecting retinal motion and for estimating the parameters of affine retinal deformations than comparable methods that currently represent the state of the art, which helps to improve the reliability of laser treatments for DME.