Top: intensity of the wavefront propagating from the sample (z = 0) to the detector plane (z = 20 mm). The linear colour scale ranges from 0 (white) to the maximum value (black). Middle: stack of the 1D images recorded as the sample is scanned across the wavefield (to the right). The colour scale is the same as in the top panel. Bottom: reconstructed and input phase aberrations in the detector plane. See text for further details.