1. A computer-based method for grouping objects within a set of digital images, wherein each image of the set of digital images includes a first object having an identity, the method comprising the steps of: identifying a plurality of nearest neighbors of each of the set of digital images within an image space defined by the set of digital images; determining a local linear structure for one or more of the set of digital images using said nearest neighbors of each of the set of digital images; and determining distances between said nearest neighbors and each digital image based upon said local linear structure.