Figure 2
From: Cycloidal-spiral sampling for three-modal x-ray CT flyscans with two-dimensional phase sensitivity
Sampling grids (shown only for a single mask period in the horizontal, px, and vertical, py, direction) for a dithered scan (a), a rotation-only scan (b), and a cycloidal-spiral scan (c). In the former case, the sample is scanned in horizontal and vertical steps of Δxopt = px/8 and Δyopt = py/8, respectively, at each rotation angle. In the latter case, the sample is displaced by horizontal and vertical (sub-period) distances of dx = Δxopt and dy = 4Δyopt, simultaneously with being rotated to the next angle.
