Automated motion correction using parallel-strip registration for wide-field en face OCT angiogram

Abstract

Abstract:We propose an innovative registration method to correct motion artifacts for widefield optical coherence tomography angiography (OCTA) acquired by ultrahigh-speed sweptsource OCT (>200 kHz A-scan rate). Considering that the number of A-scans along the fast axis is much higher than the number of positions along slow axis in the wide-field OCTA scan, a non-orthogonal scheme is introduced. Two en face angiograms in the vertical priority (2 y-fast) are divided into microsaccade-free parallel strips. A gross registration based on large vessels and a fine registration based on small vessels are sequentially applied to register parallel strips into a composite image. This technique is extended to automatically montage individual registered, motion-free angiograms into an ultrawide-field view. Werner, "En face projection imaging of the human choroidal layers with tracking SLO and swept source OCT angiography methods," Proc. SPIE 9541, 954112 (2015).

Regression-based algorithm for bulk motion subtraction in optical coherence tomography angiography

“…However, given the high prevalence of microsaccadic artifacts in OCTA, it would not eliminate the need for registration of more scans [23] in a clinical scenario. Although commercial systems have adopted various forms of real-time tracking to prevent the recording of microsaccadic motion [28,32], drifts between frames before and after microsaccades remain uncorrected, still necessitating registration of at least two volumes for truly artifact-free OCTA.…”

“…Microsaccadic motion can be corrected by registration methods [23][24][25][26][27] that retrieve the signal missing in corrupted frames from other scans. In addition, tracking-assisted scanning schemes [28][29][30][31][32] have been implemented in commercial systems to prevent data recording during a microsaccade.…”

Gabor optical coherence tomographic angiography (GOCTA) (Part I): human retinal imaging in vivo

“…However, xand y-direction based en face image registration and alignment can still be applied (e.g., [31,32]). The curvature of lens system can affect the accuracy of the evaluated retinal orientation, for slight curvature, GOCTA's images will not be affected due to the depth range of Gabor filter is 10% of the total OCT ranging depth.…”

Automated detection of dilated capillaries on optical coherence tomography angiography

“…Vesselness filters have been proven to be successful in enhancing vascular structures in OCTA [14][15][16]. We have applied it here to remove the background noise.…”