1. A method of data processing wherein a position of an object in an image is estimated from a position of a reference object in a reference image, said method comprising: learning the position of the reference object in the reference image and its relation to a set of reference landmarks in the reference image; accessing the image; accessing the relation between the position of the reference object and the set of the reference landmarks; identifying a set of landmarks in the image corresponding to the set of the reference landmarks; applying the said relation to the set of landmarks for estimating the position of the object in the image.