Figure 3

Example plots of autocorrelation and structure functions derived from SEM image shown in Fig. 1a: (a) plane projection of 2-dimensional autocorrelation function drawn with the axes of the fastest and slowest autocorrelation decays down to 0.2 value (a1 and a2, respectively), (b) 3-dimensional autocorrelation function (main peak), (c) profiles of the autocorrelation function along a1 and a2 axes, (d) log–log plot of the structure function.