1. A method for processing video data comprising a plurality of images, the plurality of images having an earlier and later frame of a video sequence, having a label for at least a first region or patch in the earlier frame and at least a second region or patch in the later frame, the method comprising: obtaining a directed graphical model of the plurality of images; and using the directed graphical model to propagate the label of the first and/or second region or patch to at least one other image of the sequence, the propagating being by a probabilistic method for estimating the label in the other image by a directed graphical method.