Blood vessel segmentation in en-face OCTA images: a frequency based method

Optical coherence tomography angiography (OCTA) is a novel noninvasive imaging modality for visualization of retinal blood flow in the human retina. Using specific OCTA imaging biomarkers for the identification of pathologies, automated image segmentations of the blood vessels can improve subsequent analysis and diagnosis. We present a novel method for the vessel identification based on frequency representations of the image, in particular, using so-called Gabor filter banks. The algorithm is evaluated on an OCTA image data set from $10$ eyes acquired by a Cirrus HD-OCT device. The segmentation outcomes received very good qualitative visual evaluation feedback and coincide well with device-specific values concerning vessel density. Concerning locality our segmentations are even more reliable and accurate. Therefore, we suggest the computation of adaptive local vessel density maps that allow straightforward analysis of retinal blood flow.