Figure 3.
Non-linear optic nerve registration scheme with representative results. Each plot consists of coronal (top row) and axial (bottom row) views of a b0 volume (left column) and a diffusion-weighted volume (right column). A: image before registration, B: Gaussian-filtered (σ = 1 voxel) image, C: initial optic nerve estimation (red curves) on B, D: Gaussian-filtered (σ = 0.5 voxel) image, E: edge detection using a Sobel filter on D, F: two-Gaussian model fitting on C and E, G: optic nerve center (red dots and curves), H: non-binary optic nerve segmentation using a Gaussian function center at the optic nerve center, I: registration of optic nerve segmentation, J: registration result of A with registered optic nerve segmentation (red overlay), K: final registration result. Note that the grayed regions (C, F, G, J, K) near the globe in the axial views were for illustration purpose to avoid distraction from misalignment beyond the anterior end of the optic nerve estimation.