]>X-Ray Phase-Contrast Imaging with Three 2D Gratings : Figure 4
827152.fig.004a
(a)
827152.fig.004b
(b)
827152.fig.004c
(c)
827152.fig.004d
(d)
Figure 4: Distributions of phase gradients.The phase object is specified in (24) with 𝑆 𝑥 = 5 and 𝑆 𝑦 = 5 . (a): the true 𝑥 -gradient; (c): the measured 𝑥 -gradient by phase stepping measurement. (b) and (d) are for the 𝑦 -gradient. The spatial unit is 𝜇 m .