Figure 3.

Processing chain to obtain the modulation transfer function (MTF) and frequency at 50% contrast (${\mathrm{f}}_{50}$) from the raw image of a half‐filled water phantom: (a) the image of the half‐filled water cylindrical phantom is acquired; (b) the edge spread function (ESF) at the air/water interface is obtained; (c) the line spread function (LSF) is calculated as the gradient of the ESF and fitted with a Gaussian to remove low‐level noise; (d) a Fourier‐transform of the LSF yields the MTF.