We subtracted the minimum value of the array from the array of j(130°) to obtain a baseline value and to remove the background (and thus low frequencies) from further analysis. Calculating the Fourier transform of each line profile j per region i provides an amplitude spectrum (Fig. ). The Fourier Transform for j(130°) showed a sharp peak, characteristic of the presence of repeating features, while the corresponding spectrum for j(40°) is flat. The integration of the spectrum provided a scalar value, Vj,i, for each orientation j, which in turn indicates the extent of high frequencies being present. The angular plot of Vj,i per region is shown in Figure . Upon summation of Vj,i over the total number I of regions, a global profile is obtained for the whole image (Fig. ). Here, we identified the most prominent angles using a peak-finding algorithm , indicated by red dots (Figs. and). We marked two dominant features with "peak 1" and "peak 2" (Fig. ).