Fig. 9.

Helical flow. The four rows (from top to bottom) are ground truth by computational fluid dynamics, reconstructed flow field using Gaussian kernel at spacings of 2 and 8 mm and thin-plate spine at spacing of 2 mm. The three columns (from left to right) are the out-of-plane velocity at the cross plane, the in-plane velocity at the cross plane and the in-plane velocity at the sagittal plane.