Fig. 4.

A closeup (left) and error image (right, scaled by a factor of 3) from one frame of (a) the gold standard image ρ(r, t), (b) the direct Fourier reconstruction from fully sampled noisy data, and (c–h) ${\{{\widehat{\mathbf{C}}}_{\text{rec},i}(\rho )\}}_{i=1}^6$ (L₁ = 14, L₂ = 32) reconstructed from sparsely sampled noisy data. The navigator data were collected using the (c) Cartesian, (d) rotated Cartesian, (e) spiral, (f) rotated spiral, (g) music note, and (h) rotated music note trajectories. Rotation of the Cartesian navigator causes spatiotemporal blurring, with examples indicated by the arrows. Regardless of rotation, the spiral and music note navigators yield similar visual quality to the unrotated Cartesian navigator.