The setup developing this idea using a liquid crystal display (LCD) (Panasonic, P13SM014, ) extracted from a commercial video projector is shown in Fig. 1(a). One important characteristics of the above-described gradient sensor is its saturation even for small wavefront local tilts without modulation. To broad the range to a useful interval, we implement the previously reported strategy10 of modulate the sensor using for illumination an incoherent symmetrical planar source that illuminates the sample from infinite. To form this source, a white led, L, (Osram, Golden Dragon LW W55M 5600 K) with the encapsulation optics removed, is collimated and passed through a ground glass diffuser, D, to form an extended uniform source of 10.5 Ø mm diameter. The diffuser is placed on the front focal plane of a lens, L1 (all the lenses in the system are doublet acromats), at its exit pupil, a distribution of simultaneous illumination directions all incoherent with each other. Given that, by technical reasons the sample cannot be directly placed on this plane, it is transported to the sample plane by means of a relay system composed of equal lenses L2 and L3 arranged as an afocal system with unit magnification. The sample, , is placed on a micrometric translation stage that allows lateral and axial positioning. A microscope consisting of an objective, MO, (Nikon, CFI PF ELWD DM 40x NA 0.60) and a tube lens, L4, is placed behind. The lens L4 forms a scaled copy of the sample-generated light field at a focal distance of the lens L5. At an additional distance in the direction of the light propagation, the LCD is placed on a three-axis micrometric translation stage. Finally, the lens L6 images the sample on a CCD camera (Andor Ixon, pixel size). The lateral position of the LCD is adjusted without the sample inserting a lens, L7 [drawn in the scheme of Fig. 1(a) with a dotted line], to focus on the CCD the spot on the LCD. After ensuring that it becomes equally occluded by the displayed patterns, the lens L7 is removed.