“…This effect, arising from the propagation of broadband X-rays through the sample, is somewhat similar to the spectral calibration function discussed in Section 4.2. Beam hardening artifacts have also been extensively investigated by numerical simulations [67,69]. It is also shown that, in the ideal case of monochromatic X-rays, the speckle contrast is modulated according to the Talbot transfer function of the heterodyne regime.…”