1. An apparatus, comprising: at least one processor; and an imaging subsystem configured to accept a plurality of particles in an imaging region of the apparatus, supply light to the imaging region, and capture images of the plurality of particles, wherein the particles have fluorescence material associated therewith; wherein the at least one processor is configured to: determine locations of selected particles of the plurality of particles within a first one of the captured images; calculate a transform that includes a radial component and a constant component, the radial component being proportional to a distance between the locations of the selected particles within the first image and a center of the first image; and determine estimated locations of the selected particles within a second one of the captured images by applying the transform to the locations of the particles within the first image.