1. A method carried out by an electronic data processor, comprising: receiving an irregular pattern of motion vectors for a target image; estimating an initial value for each of the motion vectors; using the motion vectors to generate a tap structure for an adaptive temporal prediction filter; determining an area of influence of each motion vector relative to the prediction filter; determining a prediction error of each pixel in the area of influence; determining a search window for the motion vector; comparing a size of the area of influence to a threshold value; if the size of the area of influence is larger than the threshold value, then coarsely varying the value of the motion vector within the search window to produce a first re-estimate of the value; and finely varying the first re-estimate of the value of the motion vector to produce a second re-estimate.