﹩\langle H^{\prime }_{\mathrm{hex}\,}( r) \rangle ﹩ averaged out of 100 samples of regular patterns. The solid line represents the ﹩\langle H^{\prime }_{\mathrm{hex}\,}( r) \rangle ﹩ function for the case of zero voids (example in Fig. 3a), while the dashed line represents the same function for the case of voids of 80 pixel diameter (example in Figure 3b).