1. A computer system for identifying a target person from multiple input images of the target person, comprising: for each of a plurality of known persons, a mapping from the person to a codebook derived from feature vectors of the person, each feature vector of the person being derived from an image of the person; a component that generates an input feature vector for each of the multiple input images of the target person; a component that for each known person accumulates the distances between the codebook for the person and each of the input feature vectors of the target person; and a component that, when the minimum of the accumulated distances satisfies an identification criterion, identifies the target person as the known person with the minimum of the accumulated distances.