Scatter plots showing correlations of the velocities of the same structure obtained from different methods. In (a), (b), and (c), the threshold describing the neighborhood in which we searched in the following frame for the moving brightening is set to 4 pixels, 6 pixels, and 8 pixels separately. The dashed diagonals show the ideal case of equal velocities from both methods, while the solid lines are the linear fittings. The fitting parameters can be seen in the upper left corner of each panel.