1. A method of determining motion of at least one feature present in a plurality of images, the plurality of images captured by a single camera of a scene, each of the plurality of images resulting from light passing through an aperture positioned at a different location for each of the plurality of images, the method comprising: determining the motion, in integer pixel units using a first tracking algorithm, of the at least one feature between a first image of the plurality of images and a second image of the plurality of images to obtain an integer pixel measurement of the motion; offsetting the first image and the second image according to the integer pixel measurement; determining the motion, in sub-pixel units using a second tracking algorithm, between the at least one feature in the offset first image and the second image to obtain a sub-pixel measurement; and combining the integer pixel measurement and the sub-pixel measurement to form an estimate of the motion of the at least one feature.