According to one aspect, 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 is provided. The method comprises 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.