Figure 2. Calculating an image order parameter.

(A) The equation for the order parameter used to assign an alignment score for each neighbourhood is shown, together with examples. The order parameter takes a value of 1 for complete alignment, 0 for random alignment, and −1 for orthogonal alignment. (B) A square representing a neighbourhood of 5x vectors (magenta, neighbourhood radius of 2x vectors around the central reference) is overlaid on an actin image and its corresponding alignment vector field. The black squares represent subsequent instances of such neighbourhood, as the vector field is scanned during the analysis to obtain local alignment scores. The resulting order parameters for each neighbourhood are reported in the heatmap, together with their median value, representing the output of the analysis.