Fig. 1. B-scan structural image and OCTA image: (a) structural image; (b) OCTA image with cmOCT method; (c) step-down exponential filtering method; (d) mean-subtraction method. The scale bar is 100 µm.

Fig. 2. Enhancement of the B-scan structural image: (a) original image; (b) image after depth attenuation compensation; (c) image after Eq. (7); (d) image after Eqs. (6) and (8). The scale bar is 100 µm.

Fig. 3. Cavity image: (a) original cavity image; (b) image after depth attenuation; (c) image after depth attenuation and increasing the difference between cavity and other high-scattering tissues. The scale bar is 100 µm.

Fig. 4. Flowchart of the structural image-assisted artifact reduction method.

Fig. 5. B-scan image and A-line intensity image of the artifact removal method with and without the assistance of the structural image: (a) step-down exponential filtering method; (b) mean-subtraction method; (c) step-down exponential filtering method with the structural image-assisted approach; (d) mean-subtraction method with the structural image-assisted approach; (e) structural image. The scale bar is 100 µm. The noise reference area, located above the vascular region, is marked with a white box for clarity.

Fig. 6. Effect of the structural image-assisted method: (a) en face OCTA image of the palm; (b) x–z projected images of the regions outlined by the gray rectangles in (a); (c) y–z projected images of the regions outlined by the blue rectangles in (a); (d) 3D images of the regions outlined by the green rectangles in (a). The green arrows indicate the vessel signals, while the red arrows point to the artifacts. The scale bar is 100 µm. In (b)–(d), from left to right, the sequence is the step-down exponential filtering method, mean-subtraction method, step-down exponential filtering method with the structural image-assisted approach, and mean-subtraction method with the structural image-assisted approach.