In accordance with one embodiment, a method to track persons includes generating a first and second set of facial coefficient vectors by: (i) providing a first and second image containing a plurality of persons; (ii) locating faces of persons in each image; and (iii) generating a facial coefficient vector for each face by extracting from the images coefficients sufficient to locally identify each face, then tracking the persons within the images, the tracking including comparing the first set of facial coefficient vectors to the second set of facial coefficient vectors to determine for each person in the first image if there is a corresponding person in the second image. Optically the method includes using estimated locations in combination with the vector distance between facial coefficient vectors to track persons.