A method of processing sequential frames of data comprises repeating the following steps for successive frames of data: acquiring at least a reference frame containing data points and a current frame of data points; identifying a set of anchor points in the reference frame; assigning to each anchor point in the reference frame a respective motion vector that estimates the location of the anchor point in the current frame; defining polygons formed of anchor points in the reference frame, each polygon containing data points in the reference frame, each polygon and each data point contained within the polygon having a predicted location in the current frame based on the motion vectors assigned to anchor points in the polygon; for one or more polygons in the reference frame, adjusting the number of anchor points in the reference frame based on accuracy of the predicted locations of data points in the current frame; and if the number of anchor points is increased by addition of new anchor points, then assigning motion vectors to the new anchor points that estimate the location of the anchor points in the current frame.